Educating next-generation civil engineers about smart structures technology

NASA Astrophysics Data System (ADS)

Zhang, Yunfeng

2005-05-01

The implementation of smart structures technology in the design, construction and maintenance of civil and mechanical systems have been shown beneficial to the performance enhancement, operating efficiency and reliability of structural systems. However, most of today's engineering students are unaware of the remarkable properties of smart sensors and many applications of smart structures technology. It is thus desirable to prepare the future engineers of the society for the cutting-edge technologies in smart structures, for which they may see broad application in their generation. Pioneering work in incorporating smart structures technologies into civil engineering curriculum has been done by the writer at Lehigh University and is described in this paper. In particular, a graduate-level course entitled "Smart Structural Systems" has been taught in the Spring Semester of Year 2004 at Lehigh University. To better convey the course material to students, a smart structures test-bed, which is used not only to showcase various technological aspects of a smart structural system but also offer students an opportunity to gain hands-on experience by doing experiments has been under development at Lehigh University. The hands-on experience that could be developed with the smart structures test-bed is believed being essential for students to have a good understanding and mastering of the smart structures technologies.

Manufacturing of Smart Structures Using Fiber Placement Manufacturing Processes

NASA Technical Reports Server (NTRS)

Thomas, Matthew M.; Glowasky, Robert A.; McIlroy, Bruce E.; Story, Todd A.

1996-01-01

Smart structures research and development, with the ultimate aim of rapid commercial and military production of these structures, are at the forefront of the Synthesis and Processing of Intelligent Cost-Effective Structures (SPICES) program. As part of this ARPA-sponsored program, MDA-E is using fiber placement processes to manufacture integrated smart structure systems. These systems comprise advanced composite structures with embedded fiber optic sensors, shape memory alloys, piezoelectric actuators, and miniature accelerometers. Cost-effective approaches and solutions to smart material synthesis in the fiber-placement process, based upon integrated product development, are discussed herein.

All-printed smart structures: a viable option?

NASA Astrophysics Data System (ADS)

O'Donnell, John; Ahmadkhanlou, Farzad; Yoon, Hwan-Sik; Washington, Gregory

2014-03-01

The last two decades have seen evolution of smart materials and structures technologies from theoretical concepts to physical realization in many engineering fields. These include smart sensors and actuators, active damping and vibration control, biomimetics, and structural health monitoring. Recently, additive manufacturing technologies such as 3D printing and printed electronics have received attention as methods to produce 3D objects or electronic components for prototyping or distributed manufacturing purposes. In this paper, the viability of manufacturing all-printed smart structures, with embedded sensors and actuators, will be investigated. To this end, the current 3D printing and printed electronics technologies will be reviewed first. Then, the plausibility of combining these two different additive manufacturing technologies to create all-printed smart structures will be discussed. Potential applications for this type of all-printed smart structures include most of the traditional smart structures where sensors and actuators are embedded or bonded to the structures to measure structural response and cause desired static and dynamic changes in the structure.

Adaptive smart wing design for military aircraft: requirements, concepts, and payoffs

NASA Astrophysics Data System (ADS)

Kudva, Jayanth N.; Appa, Kari; Van Way, Craig B.; Lockyer, Allen J.

1995-05-01

New developments in smart structures and materials have made it possible to revisit earlier work in adaptive and flexible wing technology, and remove some of the limitations for technology transition to next-generation aircraft. Research performed by Northrop Grumman, under internal funding, has led to a new program sponsored by ARPA to investigate the application of smart structures and materials technologies to twist and adapt and aircraft wing. Conceptual designs are presented based on state-of-the-art materials, including shape memory alloys, piezoelectrics, and fiber optic sensors for incorporation in a proposed smart wing design. Plans are described to demonstrate proof-of-concept on a prototype 1/10 scale -18 model that will be tested in a wind tunnel for final validation. Highlights of the proposed program are summarized with respect to program objectives, requirements, key concept design features, demonstration testing, and smart wing technology payoffs and risks.

Application of smart materials for improved flight performance of military aircraft

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kudva, J.; Appa, K.; Martin, C.

1995-12-31

This paper discusses on-going work under an ARPA/WL contract to Northrop Grumman entitled {open_quotes}Smart Structures and Materials Development - Smart Wing.{close_quotes} The contract addresses the application of smart materials and smart Structures concepts to enhance the aerodynamic and maneuver performance of military aircraft. Various concepts for adaptive wing and control surfaces are being studied. Specifically, (a) wing span-wise twist control using built-in shape- memory alloy torquing mechanism and (b) cambered leading edge and trailing edge control surfaces using hybrid piezoelectric and SMA actuation, are being evaluated for a 20% model of a modem day fighter aircraft. The potential benefits ofmore » the designs include increased lift for short take-offs, improved high-speed maneuverability, and enhanced control surface effectiveness. These benefits will be quantified by testing the sub-scale model in a transonic wind tunnel next year.« less

Quantification of uncertainties in the performance of smart composite structures

NASA Technical Reports Server (NTRS)

Shiao, Michael C.; Chamis, Christos C.

1993-01-01

A composite wing with spars, bulkheads, and built-in control devices is evaluated using a method for the probabilistic assessment of smart composite structures. Structural responses (such as change in angle of attack, vertical displacements, and stresses in regular plies with traditional materials and in control plies with mixed traditional and actuation materials) are probabilistically assessed to quantify their respective scatter. Probabilistic sensitivity factors are computed to identify those parameters that have a significant influence on a specific structural response. Results show that the uncertainties in the responses of smart composite structures can be quantified. Responses such as structural deformation, ply stresses, frequencies, and buckling loads in the presence of defects can be reliably controlled to satisfy specified design requirements.

General Motors and the University of Michigan smart materials and structures collaborative research laboratory

NASA Astrophysics Data System (ADS)

Brei, Diann; Luntz, Jonathan; Shaw, John; Johnson, Nancy L.; Browne, Alan L.; Alexander, Paul W.; Mankame, Nilesh D.

2007-04-01

The field of Smart Materials and Structures is evolving from high-end, one-of-a-kind products for medical, military and aerospace applications to the point of viability for mainstream affordable high volume products for automotive applications. For the automotive industry, there are significant potential benefits to be realized including reduction in vehicle mass, added functionality and design flexibility and decrease in component size and cost. To further accelerate the path from basic research and development to launched competitive products, General Motors (GM) has teamed with the College of Engineering at the University of Michigan (UM) to establish a $2.9 Million Collaborative Research Laboratory (CRL) in Smart Materials and Structures. Researchers at both GM and UM are working closely together to create leap-frog technologies which start at conceptualization and proceed all the way through demonstration and handoff to product teams, thereby bridging the traditional technology gap between industry and academia. In addition to Smart Device Technology Innovation, other thrust areas in the CRL include Smart Material Maturity with a basic research focus on overcoming material issues that form roadblocks to commercialism and Mechamatronic System Design Methodology with an applied focus on development tools (synthesis and analysis) to aid the engineer in application of smart materials to system engineering. This CRL is a global effort with partners across the nation and world from GM's Global Research Network such as HRL Laboratories in California and GM's India Science Lab in Bangalore, India. This paper provides an overview of this new CRL and gives examples of several of the projects underway.

Results of thermal modeling of Smart Energy Coating with phase-transition material for independent electricity generation

NASA Astrophysics Data System (ADS)

Pospelova, I. Y.; Pospelova, M. Y.; Bondarenko, A. S.; Kornilov, D. A.

2018-05-01

The modeling for Smart Energy Coating is presented. The coating is able to produce electricity on the surface of pipelines and structural elements. Along with electric output, Smart Energy Coating ensures the stable temperature conditions of work for structures, pipelines and regulating elements. The energy production scheme is based on the Peltier principle and the insulating layer with a phase transition. Thermally conductive inclusions of the inside layer with a phase transition material ensure the stable operation of the Peltier element.

Constitutive modeling and control of 1D smart composite structures

NASA Astrophysics Data System (ADS)

Briggs, Jonathan P.; Ostrowski, James P.; Ponte-Castaneda, Pedro

1998-07-01

Homogenization techniques for determining effective properties of composite materials may provide advantages for control of stiffness and strain in systems using hysteretic smart actuators embedded in a soft matrix. In this paper, a homogenized model of a 1D composite structure comprised of shape memory alloys and a rubber-like matrix is presented. With proportional and proportional/integral feedback, using current as the input state and global strain as an error state, implementation scenarios include the use of tractions on the boundaries and a nonlinear constitutive law for the matrix. The result is a simple model which captures the nonlinear behavior of the smart composite material system and is amenable to experiments with various control paradigms. The success of this approach in the context of the 1D model suggests that the homogenization method may prove useful in investigating control of more general smart structures. Applications of such materials could include active rehabilitation aids, e.g. wrist braces, as well as swimming/undulating robots, or adaptive molds for manufacturing processes.

Vibration reduction for smart periodic structures via periodic piezoelectric arrays with nonlinear interleaved-switched electronic networks

NASA Astrophysics Data System (ADS)

Bao, Bin; Guyomar, Daniel; Lallart, Mickaël

2017-01-01

Smart periodic structures covered by periodically distributed piezoelectric patches have drawn more and more attention in recent years for wave propagation attenuation and corresponding structural vibration suppression. Since piezoelectric materials are special type of energy conversion materials that link mechanical characteristics with electrical characteristics, shunt circuits coupled with such materials play a key role in the wave propagation and/or vibration control performance in smart periodic structures. Conventional shunt circuit designs utilize resistive shunt (R-shunt) and resonant shunt (RL-shunt). More recently, semi-passive nonlinear approaches have also been developed for efficiently controlling the vibrations of such structures. In this paper, an innovative smart periodic beam structure with nonlinear interleaved-switched electric networks based on synchronized switching damping on inductor (SSDI) is proposed and investigated for vibration reduction and wave propagation attenuation. Different from locally resonant band gap mechanism forming narrow band gaps around the desired resonant frequencies, the proposed interleaved electrical networks can induce new broadly low-frequency stop bands and broaden primitive Bragg stop bands by virtue of unique interleaved electrical configurations and the SSDI technique which has the unique feature of realizing automatic impedance adaptation with a small inductance. Finite element modeling of a Timoshenko electromechanical beam structure is also presented for validating dispersion properties of the structure. Both theoretical and experimental results demonstrate that the proposed beam structure not only shows better vibration and wave propagation attenuation than the smart beam structure with independent switched networks, but also has technical simplicity of requiring only half of the number of switches than the independent switched network needs.

International Conference on Control and Estimation of Distributed Parameter Systems: Nonlinear Phenomena Held in Vorau, Austria on July 18-24, 1993

DTIC Science & Technology

1993-07-24

detection anit charact(erization in smart material structures 21 NI. BER;OUNIoUX, T. N’IANNIKK6) AN) D. TmIA: Optimnality conditions for non-qumalified...UISA DAMAGE DETECTION AND CHARACTERIZATION IN SMART MATERIAL STRUCTURES HI. TF. BANKS AND) Y, WAN(, C~enter for Rtsvarchliti Scientific Cumpiptatioii...111,u’, + +pt,’, ,x 123 22 (3.3) 0~’ ={( othi’i-wist’. Wie iitmt sought to dlemnonstrat~e tiht capabliity of1 pieoll"t~tItrit m~aterialds inl smart

Animal Hairs as Water-stimulated Shape Memory Materials: Mechanism and Structural Networks in Molecular Assemblies

NASA Astrophysics Data System (ADS)

Xiao, Xueliang; Hu, Jinlian

2016-05-01

Animal hairs consisting of α-keratin biopolymers existing broadly in nature may be responsive to water for recovery to the innate shape from their fixed deformation, thus possess smart behavior, namely shape memory effect (SME). In this article, three typical animal hair fibers were first time investigated for their water-stimulated SME, and therefrom to identify the corresponding net-points and switches in their molecular and morphological structures. Experimentally, the SME manifested a good stability of high shape fixation ratio and reasonable recovery rate after many cycles of deformation programming under water stimulation. The effects of hydration on hair lateral size, recovery kinetics, dynamic mechanical behaviors and structural components (crystal, disulfide and hydrogen bonds) were then systematically studied. SME mechanisms were explored based on the variations of structural components in molecular assemblies of such smart fibers. A hybrid structural network model with single-switch and twin-net-points was thereafter proposed to interpret the water-stimulated shape memory mechanism of animal hairs. This original work is expected to provide inspiration for exploring other natural materials to reveal their smart functions and natural laws in animals including human as well as making more remarkable synthetic smart materials.

Animal Hairs as Water-stimulated Shape Memory Materials: Mechanism and Structural Networks in Molecular Assemblies

PubMed Central

Xiao, Xueliang; Hu, Jinlian

2016-01-01

Animal hairs consisting of α-keratin biopolymers existing broadly in nature may be responsive to water for recovery to the innate shape from their fixed deformation, thus possess smart behavior, namely shape memory effect (SME). In this article, three typical animal hair fibers were first time investigated for their water-stimulated SME, and therefrom to identify the corresponding net-points and switches in their molecular and morphological structures. Experimentally, the SME manifested a good stability of high shape fixation ratio and reasonable recovery rate after many cycles of deformation programming under water stimulation. The effects of hydration on hair lateral size, recovery kinetics, dynamic mechanical behaviors and structural components (crystal, disulfide and hydrogen bonds) were then systematically studied. SME mechanisms were explored based on the variations of structural components in molecular assemblies of such smart fibers. A hybrid structural network model with single-switch and twin-net-points was thereafter proposed to interpret the water-stimulated shape memory mechanism of animal hairs. This original work is expected to provide inspiration for exploring other natural materials to reveal their smart functions and natural laws in animals including human as well as making more remarkable synthetic smart materials. PMID:27230823

Performance of Integrated Fiber Optic, Piezoelectric, and Shape Memory Alloy Actuators/Sensors in Thermoset Composites

NASA Technical Reports Server (NTRS)

Trottier, C. Michael

1996-01-01

Recently, scientists and engineers have investigated the advantages of smart materials and structures by including actuators in material systems for controlling and altering the response of structural environments. Applications of these materials systems include vibration suppression/isolation, precision positioning, damage detection and tunable devices. Some of the embedded materials being investigated for accomplishing these tasks include piezoelectric ceramics, shape memory alloys, and fiber optics. These materials have some benefits and some shortcomings; each is being studied for use in active material design in the SPICES (Synthesis and Processing of Intelligent Cost Effective Structures) Consortium. The focus of this paper concerns the manufacturing aspects of smart structures by incorporating piezoelectric ceramics, shape memory alloys and fiber optics in a reinforced thermoset matrix via resin transfer molding (RTM).

Modeling the Behaviour of an Advanced Material Based Smart Landing Gear System for Aerospace Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varughese, Byji; Dayananda, G. N.; Rao, M. Subba

2008-07-29

The last two decades have seen a substantial rise in the use of advanced materials such as polymer composites for aerospace structural applications. In more recent years there has been a concerted effort to integrate materials, which mimic biological functions (referred to as smart materials) with polymeric composites. Prominent among smart materials are shape memory alloys, which possess both actuating and sensory functions that can be realized simultaneously. The proper characterization and modeling of advanced and smart materials holds the key to the design and development of efficient smart devices/systems. This paper focuses on the material characterization; modeling and validationmore » of the model in relation to the development of a Shape Memory Alloy (SMA) based smart landing gear (with high energy dissipation features) for a semi rigid radio controlled airship (RC-blimp). The Super Elastic (SE) SMA element is configured in such a way that it is forced into a tensile mode of high elastic deformation. The smart landing gear comprises of a landing beam, an arch and a super elastic Nickel-Titanium (Ni-Ti) SMA element. The landing gear is primarily made of polymer carbon composites, which possess high specific stiffness and high specific strength compared to conventional materials, and are therefore ideally suited for the design and development of an efficient skid landing gear system with good energy dissipation characteristics. The development of the smart landing gear in relation to a conventional metal landing gear design is also dealt with.« less

Adoption of Smart Structures for Prevention of Health Hazards in Buildings

NASA Astrophysics Data System (ADS)

Oke, Ayodeji; Aigbavboa, Clinton; Ngema, Wiseman

2017-11-01

The importance of building quality to the health and well-being of occupants and surrounding neighbors cannot be overemphasized. Smart structures were construed to proffer solution to various issues of sustainable development including social factors that is concerned with health and safety of people. Based on existing literature materials on building quality, smart structures and general aspect of sustainable developments, this study examined the benefits of smart structures in the prevention of various health issues in infrastructural buildings, which has been a concern for stakeholders in the architecture, engineering and construction industry. The criterion for indoor environmental quality was adopted and various health and bodily issues related to building quality were explained. The adoption of smart structure concept will help to manage physical, chemical, biological and psychological factors of building with a view to enhancing better quality of life of occupants.

Smart Actuators and Adhesives for Reconfigurable Matter.

PubMed

Ko, Hyunhyub; Javey, Ali

2017-04-18

Biological systems found in nature provide excellent stimuli-responsive functions. The camouflage adaptation of cephalopods (octopus, cuttlefish), rapid stiffness change of sea cucumbers, opening of pine cones in response to humidity, and rapid closure of Venus flytraps upon insect touch are some examples of nature's smart systems. Although current technologies are still premature to mimic these sophisticated structures and functions in smart biological systems, recent work on stimuli-responsive programmable matter has shown great progress. Stimuli-responsive materials based on hydrogels, responsive nanocomposites, hybrid structures, shape memory polymers, and liquid crystal elastomers have demonstrated excellent responsivities to various stimuli such as temperature, light, pH, and electric field. However, the technologies in these stimuli-responsive materials are still not sophisticated enough to demonstrate the ultimate attributes of an ideal programmable matter: fast and reversible reconfiguration of programmable matter into complex and robust shapes. Recently, reconfigurable (or programmable) matter that reversibly changes its structure/shape or physical/chemical properties in response to external stimuli has attracted great interest for applications in sensors, actuators, robotics, and smart systems. In particular, key attributes of programmable matter including fast and reversible reconfiguration into complex and robust 2D and 3D shapes have been demonstrated by various approaches. In this Account, we review focused areas of smart materials with special emphasis on the material and device structure designs to enhance the response time, reversibility, multistimuli responsiveness, and smart adhesion for efficient shape transformation and functional actuations. First, the capability of fast reconfiguration of 2D and 3D structures in a reversible way is a critical requirement for programmable matter. For the fast and reversible reconfiguration, various approaches based on enhanced solvent diffusion rate through the porous or structured hydrogel materials, electrostatic repulsion between cofacial electrolyte nanosheets, and photothermal actuation are discussed. Second, the ability to reconfigure programmable matters into a variety of complex structures is beneficial for the use of reconfigurable matter in diverse applications. For the reconfiguration of planar 2D structures into complex 3D structures, asymmetric and multidirectional stress should be applied. In this regard, local hinges with stimuli-responsive stiffness, multilayer laminations with different responsiveness in individual layers, and origami and kirigami assembly approaches are reviewed. Third, multistimuli responsiveness will be required for the efficient reconfiguration of complex programmable matter in response to user-defined stimulus under different chemical and physical environments. In addition, with multistimuli responsiveness, the reconfigured shape can be temporarily affixed by one signal and disassembled by another signal at a user-defined location and time. Photoactuation depending on the chirality of carbon nanotubes and composite gels with different responsiveness will be discussed. Finally, the development of smart adhesives with on-demand adhesion strength is critically required to maintain the robust reconfigurable shapes and for the switching on/off of the binding between components or with target objects. Among various connectors and adhesives, thermoresponsive nanowire connectors, octopus-inspired smart adhesives, and elastomeric tiles with soft joints are described due to their potential applications in joints of deformable 3D structures and smart gripping systems.

Auxetics in smart systems and structures 2013

NASA Astrophysics Data System (ADS)

Scarpa, Fabrizio; Ruzzene, Massimo; Alderson, Andrew; Wojciechowski, Krzysztof W.

2013-08-01

Auxetics comes from the Greek (auxetikos), meaning 'that which tends to expand'. The term indicates specifically materials and structures with negative Poisson's ratio (NPR). Although the Poisson's ratio is a mechanical property, auxetic solids have shown evidence of multifunctional characteristics, ranging from increased stiffness and indentation resistance, to energy absorption under static and dynamic loading, soundproofing qualities and dielectric tangent loss. NPR solids and structures have also been used in the past as material platforms to build smart structural systems. Auxetics in general can be considered also a part of the 'negative materials' field, which includes solids and structures exhibiting negative thermal expansion, negative stiffness and compressibility. All these unusual deformation characteristics have the potential to provide a significant contribution to the area of smart materials systems and structures. In this focus issue, we are pleased to present some examples of novel multifunctional behaviors provided by auxetic, negative stiffness and negative compressibility in smart systems and structures. Particular emphasis has been placed upon the multidisciplinary and systems approach provided by auxetics and negative materials, also with examples applied to energy absorption, vibration damping, structural health monitoring and active deployment aspects. Three papers in this focus issue provide significant new clarifications on the role of auxeticity in the mechanical behavior of shear deformation in plates (Lim), stress wave characteristics (Lim again), and thermoelastic damping (Maruszewski et al ). Kochmann and Venturini describe the performance of auxetic composites in finite strain elasticity. New types of microstructures for auxetic systems are depicted for the first time in three works by Ge et al , Zhang et al , and Kim and co-workers. Tubular auxetic structures and their mechanical performance are also analyzed by Karnessis and Burriesci. Foams with negative Poisson's ratio constitute one of the main examples of auxetic materials available. The focus issue presents two papers on this topic, one on a novel microstructure numerical modeling technique (Pozniak et al ), the other on experimental and model identification results of linear and nonlinear vibration behavior (Bianchi and Scarpa). Nonlinearity (now in wave propagation for SHM applications) is also investigated by Klepka and co-workers, this time in auxetic chiral sandwich structures. Vibration damping and nonlinear behavior is also a key feature of the auxetic structural damper with metal rubber particles proposed by Ma et al . Papers on negative material properties are introduced by the negative stiffness and high-frequency damper concept proposed by Kalathur and Lakes. A cellular structure exhibiting a zero Poisson's ratio, together with zero and negative stiffness, is presented in the work of Virk and co-workers. Negative compressibility is examined by Grima et al in truss-type structures with constrained angle stretching. Finally, Grima and co-workers propose a concept of tunable auxetic metamaterial with magnetic inclusions for multifunctional applications. Acknowledgments We would like to thank all the authors for their high quality contributions. Special thanks go also to the Smart Materials and Structures Editorial Board and the IOP Publishing team, with particular mention to Natasha Leeper and Bethan Davies for their continued support in arranging this focus issue in Smart Materials and Structures .

Smart materials and structures

NASA Technical Reports Server (NTRS)

Rogowski, Robert S.; Heyman, Joseph S.

1993-01-01

Embedded optical fibers allow not only the cure-monitoring and in-service lifetime measurements of composite materials, but the NDE of material damage and degradation with aging. The capabilities of such damage-detection systems have been extended to allow the quantitative determination of 2D strain in materials by several different methods, including the interferometric and the numerical. It remains to be seen, what effect the embedded fibers have on the strength of the 'smart' materials created through their incorporation.

Defence Applications

DTIC Science & Technology

2007-03-01

nano-energetics and new types of catalysts), reduced cost of maintenance (for example through wear reduction, self - healing and self -repair), enhanced...materials • Self - healing ( self -repair) material • Smart skin materials • Adaptive camouflage • Adaptive structures Defence Applications 6 - 2 RTO-EN...type of atom or a single molecule to a site at which it might be required. Smart drug delivery and self - healing follows on from such a capability

Transparent Large Strain Thermoplastic Polyurethane Magneto-Active Nanocomposites

NASA Technical Reports Server (NTRS)

Yoonessi, Mitra; Carpen, Ileana; Peck, John; Sola, Francisco; Bail, Justin; Lerch, Bradley; Meador, Michael

2010-01-01

Smart adaptive materials are an important class of materials which can be used in space deployable structures, morphing wings, and structural air vehicle components where remote actuation can improve fuel efficiency. Adaptive materials can undergo deformation when exposed to external stimuli such as electric fields, thermal gradients, radiation (IR, UV, etc.), chemical and electrochemical actuation, and magnetic field. Large strain, controlled and repetitive actuation are important characteristics of smart adaptive materials. Polymer nanocomposites can be tailored as shape memory polymers and actuators. Magnetic actuation of polymer nanocomposites using a range of iron, iron cobalt, and iron manganese nanoparticles is presented. The iron-based nanoparticles were synthesized using the soft template (1) and Sun's (2) methods. The nanoparticles shape and size were examined using TEM. The crystalline structure and domain size were evaluated using WAXS. Surface modifications of the nanoparticles were performed to improve dispersion, and were characterized with IR and TGA. TPU nanocomposites exhibited actuation for approximately 2wt% nanoparticle loading in an applied magnetic field. Large deformation and fast recovery were observed. These nanocomposites represent a promising potential for new generation of smart materials.

Multi-stage responsive 4D printed smart structure through varying geometric thickness of shape memory polymer

NASA Astrophysics Data System (ADS)

Teoh, Joanne Ee Mei; Zhao, Yue; An, Jia; Chua, Chee Kai; Liu, Yong

2017-12-01

Shape memory polymers (SMPs) have gained a presence in additive manufacturing due to their role in 4D printing. They can be printed either in multi-materials for multi-stage shape recovery or in a single material for single-stage shape recovery. When printed in multi-materials, material or material-based design is used as a controlling factor for multi-stage shape recovery. However, when printed in a single material, it is difficult to design multi-stage shape recovery due to the lack of a controlling factor. In this research, we explore the use of geometric thickness as a controlling factor to design smart structures possessing multi-stage shape recovery using a single SMP. L-shaped hinges with a thickness ranging from 0.3-2 mm were designed and printed in four different SMPs. The effect of thickness on SMP’s response time was examined via both experiment and finite element analysis using Ansys transient thermal simulation. A method was developed to accurately measure the response time in millisecond resolution. Temperature distribution and heat transfer in specimens during thermal activation were also simulated and discussed. Finally, a spiral square and an artificial flower consisting of a single SMP were designed and printed with appropriate thickness variation for the demonstration of a controlled multi-stage shape recovery. Experimental results indicated that smart structures printed using single material with controlled thickness parameters are able to achieve controlled shape recovery characteristics similar to those printed with multiple materials and uniform geometric thickness. Hence, the geometric parameter can be used to increase the degree of freedom in designing future smart structures possessing complex shape recovery characteristics.

Fiber optic smart structures and skins V; Proceedings of the Meeting, Boston, MA, Sept. 8, 9, 1992

NASA Technical Reports Server (NTRS)

Claus, Richard O. (Editor); Rogowski, Robert S. (Editor)

1993-01-01

The present conference discusses the materials used in applications of fiber-optics (F-O) to smart structures, extrinsic Fabry-Perot interferometric F-O sensors, sapphire F-O sensors, two-mode F-O sensors with photoinduced refractive index, an F-O accelerometer using two-mode fibers, and embedded F-O acoustic sensors for flaw detection. Also discussed are an optoelectronic smart structure interface, F-O sensors for simultaneous detection of strain and temperature, an optical Mach-Zehnder interferometer for smart skins, a split-cavity cross-coupled extrinsic fiber interferometer, and an embedded Bragg grating F-O sensor for composite flexbeams, an Er-doped ring-laser strain sensor.

Adaptive and active materials: selected papers from the ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 12) (Stone Mountain, GA, USA, 19-21 September 2012)

NASA Astrophysics Data System (ADS)

Seelecke, Stefan; Erturk, Alper; Ounaies, Zoubeida; Naguib, Hani; Huber, John; Turner, Travis; Anderson, Iain; Philen, Michael; Baba Sundaresan, Vishnu

2013-09-01

The fifth annual meeting of the ASME/AIAA Smart Materials, Adaptive Structures and Intelligent Systems Conference (SMASIS) was held in beautiful Stone Mountain near Atlanta, GA. It is the conference's objective to provide an up-to-date overview of research trends in the entire field of smart materials systems. This was reflected in keynote speeches by Professor Eduard Arzt (Institute of New Materials and Saarland University, Saarbrücken, Germany) on 'Micro-patterned artificial 'Gecko' surfaces: a path to switchable adhesive function', by Professor Ray H Baughman (The Alan G MacDiarmid NanoTech Institute, University of Texas at Dallas) on 'The diverse and growing family of carbon nanotube and related artificial muscles', and by Professor Richard James (University of Minnesota) on 'The direct conversion of heat to electricity using multiferroic materials with phase transformations'. SMASIS 2012 was divided into eight symposia which span basic research, applied technological design and development, and industrial and governmental integrated system and application demonstrations. • SYMP 1. Development and characterization of multifunctional materials. • SYMP 2. Mechanics and behavior of active materials. • SYMP 3. Modeling, simulation and control of adaptive systems. • SYMP 4. Integrated system design and implementation. • SYMP 5. Structural health monitoring/NDE. • SYMP 6. Bio-inspired materials and systems. • SYMP 7. Energy harvesting. • SYMP 8. Structural and materials logic. This year we were particularly excited to introduce a new symposium on energy harvesting, which has quickly matured from a special track in previous years to an independent symposium for the first time. The subject cuts across fields by studying different materials, ranging from piezoelectrics to electroactive polymers, as well as by emphasizing different energy sources from wind to waves and ambient vibrations. Modeling, experimental studies, and technology applications all belong to the symposium topics. In addition, the conference also featured a special symposium dedicated to DARPA's structural and materials/logic program. The program seeks to enable structural systems to adapt to varying loads and simultaneously exhibit both high stiffness and high damping. Authors of selected papers in the materials areas (symposia 1, 2, and 6) as well as energy harvesting (symposium 7) were invited to write a full journal article on their presentation topic for publication in this special issue of Smart Materials and Structures . This collection of papers demonstrates the exceptional quality and originality of the conference presentations. We are very appreciative of their efforts to produce this collection of highly relevant articles on smart materials.

Optical signal processing of spatially distributed sensor data in smart structures

NASA Technical Reports Server (NTRS)

Bennett, K. D.; Claus, R. O.; Murphy, K. A.; Goette, A. M.

1989-01-01

Smart structures which contain dense two- or three-dimensional arrays of attached or embedded sensor elements inherently require signal multiplexing and processing capabilities to permit good spatial data resolution as well as the adequately short calculation times demanded by real time active feedback actuator drive circuitry. This paper reports the implementation of an in-line optical signal processor and its application in a structural sensing system which incorporates multiple discrete optical fiber sensor elements. The signal processor consists of an array of optical fiber couplers having tailored s-parameters and arranged to allow gray code amplitude scaling of sensor inputs. The use of this signal processor in systems designed to indicate the location of distributed strain and damage in composite materials, as well as to quantitatively characterize that damage, is described. Extension of similar signal processing methods to more complicated smart materials and structures applications are discussed.

EDITORIAL: Adaptive and active materials: Selected papers from the ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 11) (Scottsdale, AZ, USA, 18-21 September 2011) Adaptive and active materials: Selected papers from the ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 11) (Scottsdale, AZ, USA, 18-21 September 2011)

NASA Astrophysics Data System (ADS)

Brei, Diann

2012-09-01

The fourth annual meeting of the ASME/AIAA Smart Materials, Adaptive Structures and Intelligent Systems Conference (SMASIS) took place in sunny Scottsdale, Arizona. Each year we strive to grow and offer new experiences. This year we held a special Guest Symposium on Sustainability along with two focused topic tracks on energy harvesting and active composites to encourage cross-fertilization between these important fields and our community. This cross-disciplinary emphasis was reflected in keynote talks by Dr Wayne Brown, President and founder of Dynalloy, Inc., 'Cross-Discipline Sharing'; Dr Brad Allenby, Arizona State University, 'You Want the Future? You can't Handle the Future!'; and Professor Aditi Chattopadhyay, Arizona State University, 'A Multidisciplinary Approach to Structural Health Monitoring and Prognosis'. SMASIS continues to grow our community through both social and technical interchange. The conference location, the exotic Firesky Resort and Spa, exemplified the theme of our Guest Symposium on Sustainability, being the only Green Seal certified resort in Arizona, and highlighting four elements thought to represent all that exist: fire, water, earth and air. Several special events were held around this theme including the night at the oasis reception sponsored by General Motors, sustainability bingo, smart trivia and student networking lunches, and an Arizona pow-wow with a spectacular Indian hoop dance. Our student and young professional development continues to grow strong with best paper and hardware competitions, scavenger student outing and games night. We are very proud that our students and young professionals are always seeking out ways to give back to the community, including organizing outreach to local high school talent. We thank all of our sponsors who made these special events possible. We hope that these social events provided participants with the opportunity to expand their own personal community and broaden their horizons. Our ultimate goal was to provide a friendly, casual southwestern forum for the exchange of the 'hottest' ideas and latest results. Our sincere appreciation goes to all the presenters for choosing to share their very best work at this conference. SMASIS is divided into seven symposia which span basic research, applied technological design and development, and industrial and governmental integrated system and application demonstrations: SYMP 1 Multifunctional Materials; SYMP 2 Active Materials, Mechanics and Behavior; SYMP 3 Modeling, Simulation and Control; SYMP 4 Enabling Technologies and Integrated System Design; SYMP 5 Structural Health Monitoring/NDE; SYMP 6 Bio-inspired Smart Materials and Structures; and SYMP 7 Guest Symposium on Sustainability. In addition, the conference introduced a new student and young professional development symposium. Authors of papers in the materials area (symposia 1, 2 and 6) were invited to write a full journal article on their presentation topic for publication in this Special Issue of Smart Materials and Structures. This collection of papers demonstrates the exceptional quality and originality of the conference presentations. We appreciate their efforts in producing this collection of highly relevant articles on smart materials.

Australian defence requirements and initiatives in smart materials and structures

NASA Astrophysics Data System (ADS)

Wilson, Alan R.; Galea, Stephen C.; Scala, Christine; Wong, Albert

2002-11-01

The Australian Defence Force is increasingly facing escalating costs on through-life support for major platforms (ships, aircraft and land vehicles). The application of smart materials and structures technologies in platform management systems is seen as a very promising approach to reduce these costs and to potentially achieve significant enhancement of platform capability. A new DSTO Key Initiative, 'Smart Materials and Structures', has been recently developed and funded to address these technologies. The Initiative will build on and grow the current activities within DSTO and promote collaboration with external Australian institutes and industry. This paper will present an overview of the Initiative and the generic sensor and system issues inherent in the 'whole-of-platform' and 'whole-of-life' monitoring and management of major defence platforms. Examples for some particular elements of this will be drawn from current work in DSTO. Other presentations in the conference will cover the technical and scientific aspects of these in more detail.

Overview of the ARPA/WL Smart Structures and Materials Development-Smart Wing contract

NASA Astrophysics Data System (ADS)

Kudva, Jayanth N.; Jardine, A. Peter; Martin, Christopher A.; Appa, Kari

1996-05-01

While the concept of an adaptive aircraft wing, i.e., a wing whose shape parameters such as camber, wing twist, and thickness can be varied to optimize the wing shape for various flight conditions, has been extensively studied, the complexity and weight penalty of the actuation mechanisms have precluded their practical implementation. Recent development of sensors and actuators using smart materials could potentially alleviate the shortcomings of prior designs, paving the way for a practical, `smart' adaptive wing which responds to changes in flight and environmental conditions by modifying its shape to provide optimal performance. This paper presents a summary of recent work done on adaptive wing designs under an on-going ARPA/WL contract entitled `Smart Structures and Materials Development--Smart Wing.' Specifically, the design, development and planned wind tunnel testing of a 16% model representative of a fighter aircraft wing and incorporating the following features, are discussed: (1) a composite wing torque box whose span-wise twist can be varied by activating built-in shape memory alloy (SMA) torque tubes to provide increased lift and enhanced maneuverability at multiple flight conditions, (2) trailing edge control surfaces deployed using composite SMA actuators to provide smooth, hingeless aerodynamic surfaces, and (3) a suite of fiber optic sensors integrated into the wing skin which provide real-time strain and pressure data to a feedback control system.

Fabrication and testing of SMA composite beam with shape control

NASA Astrophysics Data System (ADS)

Noolvi, Basavaraj; S, Raja; Nagaraj, Shanmukha; Mudradi, Varada Raj

2017-07-01

Smart materials are the advanced materials that have characteristics of sensing and actuation in response to the external stimuli like pressure, heat or electric charge etc. These materials can be integrated in to any structure to make it smart. From the different types of smart materials available, Shape Memory Alloy (SMA) is found to be more useful in designing new applications, which can offer more actuating speed, reduce the overall weight of the structure. The unique property of SMA is the ability to remember and recover from large strains of upto 8% without permanent deformation. Embedding the SMA wire/sheet in fiber-epoxy/flexible resin systems has many potential applications in Aerospace, Automobile, Medical, Robotics and various other fields. In this work the design, fabrication, and testing of smart SMA composite beam has been carried out. Two types of epoxy based resin systems namely LY 5210 resin system and EPOLAM 2063 resin system are used in fabricating the SMA composite specimens. An appropriate mould is designed and fabricated to retain the pre-strain of SMA wire during high temperature post curing of composite specimens. The specimens are fabricated using vacuum bag technique.

Fiber optics in composite materials: materials with nerves of glass

NASA Astrophysics Data System (ADS)

Measures, Raymond M.

1990-08-01

A Fiber Optic BasedSmart Structure wiipossess a structurally integrated optical microsensor system for determining its state. This built-in sensor system should, in real-time, be able to: evaluate the strain or deformation of a structure, monitor if its vibrating or subject to excessive loads, check its temperature and warn of the appearance of any hot spots. In addition a Smart Structure should maintain a vigilant survelliance over its structural integrity. The successful development of Smart StructureTechnolgy could lead to: aircraft that are safer, lighter, more efficient, easier to maintain and to service; pipelines, pressure vessels and storage tanks that constantly monitor their structuralintegrity and immediately issue an alert ifany problem is detected; space platforms that check forpressure leaks, unwanted vibration, excess thermal buildup, and deviation from some preassigned shape.This technology is particularly appropriate for composite materials where internal damage generated by: impacts, manufacturing flaws, excessive loading or fatigue could be detected and assessed. In service monitoring of structural loads, especially in regions like wing roots of aircraft, could be ofconsiderable benefit in helping to avoid structural overdesign and reduce weight. Structurally imbedded optical fibers sensors might also serve to monitor the cure state of composite thermosets during their fabrication and thereby contribute to improved quality control of these products.

Variable stiffness mechanisms with SMA actuators

NASA Astrophysics Data System (ADS)

Siler, Damin J.; Demoret, Kimberly B. J.

1996-05-01

Variable stiffness is a new branch of smart structures development with several applications related to aircraft. Previous research indicates that temporarily reducing the stiffness of an airplane wing can decrease control actuator sizing and improve aeroelastic roll performance. Some smart materials like shape memory alloys (SMA) can change their material stiffness properties, but they tend to gain stiffness in their `power on' state. An alternative is to integrate mechanisms into a structure and change stiffness by altering boundary conditions and structural load paths. An innovative concept for an axial strut mechanism was discovered as part of research into variable stiffness. It employs SMA springs (specifically Ni-Ti) in a way that reduces overall stiffness when the SMA springs gain stiffness. A simplified mathematical model for static analysis was developed, and a 70% reduction in stiffness was obtained for a particular selection of springs. The small force capacity of commercially available SMA springs limits the practicality of this concept for large load applications. However, smart material technology is still immature, and future advances may permit development of a heavy-duty, variable stiffness strut that is small and light enough for use in aircraft structures.

EDITORIAL Smart materials, multifunctional composites, and morphing structures: selected papers from the 20th International Conference on Adaptive Structures and Technologies (ICAST 2009) Smart materials, multifunctional composites, and morphing structures: selected papers from the 20th International Conference on Adaptive Structures and Technologies (ICAST 2009)

NASA Astrophysics Data System (ADS)

Liao, Wei-Hsin

2010-12-01

The 20th International Conference on Adaptive Structures and Technologies (ICAST) was held on 20-22 October 2009 in Hong Kong. This special section of Smart Materials and Structures is derived from the research papers presented at the conference. Of the 106 papers presented at the conference, 11 papers were reviewed and accepted for this special section, following the regular review procedures of the journal. This special section is focused on smart materials, multifunctional composites, and applications on morphing structures. Smart materials. Smart materials are the foundation of adaptive structures and intelligent systems. The development of new materials will lead to significant improvement in various applications. Three articles are focused on the fabrication of new materials and investigation of their behaviors: Barium strontium zirconate titanate ((Ba1-xSrx)(ZrxTi1-x)O3; BSZT, x = 0.25 and 0.75) ceramics with a highly crystalline structure were fabricated using the combustion technique. The microstructure of BSZT powders exhibited an almost-spherical morphology and had a porous agglomerated form. Polyaniline (PANI)/clay nanoparticles with unique core-shell structure were synthesized via Pickering emulsion polymerization. By dispersing PANI/clay nanoparticles in silicone oil, the ER fluid was made. Magnetic field effects were investigated on the deposition rate and surface morphology of chromium nitride coatings deposited by magnetron sputtering for superior hardness, excellent wear and oxidation resistance. The surface morphology of chromium nitride films was also examined by a scanning electron microscope (SEM). Multifunctional composites. Composites are made from two or more constituent materials so they can combine the best properties of different materials. Five papers deal with fabrication, testing, and modeling of various multifunctional composites: A new active structural fiber (ASF) was fabricated by coating a single carbon fiber with a concentric PZT (PbZr0.52Ti0.48O3) shell using electrolytic deposition. This new ASF is expected to have broader applications due to the higher piezoelectric coupling effect with the use of carbon fiber and PZT. The sol-gel technique was employed to deposit lead zirconium titanium (PZT) and silica composite film onto a copper (Cu)/polyimide (PI) flexible structure. The fabricated PZT-silica composite films were then used for flexible actuator and sensor applications. Interfacial properties and hydrophobicity of multifunctional Ni-nanopowder/epoxy composites were evaluated for self-sensing and actuation. The effects of water content on the actuation performance of ionic polymer-metal composites (IPMCs) were investigated experimentally. Multiscale modelling of a composite electroactive polymer structure was developed, in particular for tubular actuators. The models were validated with experimental data. Morphing structures. Three papers relate to morphing skins and structures. Several issues including stiffness and energy consumption were explored: Composite corrugated structures were used as morphing skin panels (MSPs) in the trailing edge region of a scaled morphing aerofoil section. Wind tunnel testing was carried out to demonstrate the MSP concept. Optimization of a variable-stiffness skin was performed for morphing high-lift devices. The objective is to design the structure to have high enough stiffness to withstand aerodynamic loading and yet low enough stiffness to enable morphing. The aerodynamic and actuation loads were taken into consideration during the optimization. Two adaptive and morphing structures were proposed for low-energy consumption or even energy-harvesting green buildings with the use of an optimization process. Searching for optimal solutions was done by means of an evolutionary technique while the compatibility of the resulting configurations of the adaptive envelope was ensured by the virtual force density method. We would like to thank all of the authors for their significant contributions to this special section for Smart Materials and Structures. We are also grateful to all of the reviewers and associate editors who handled the reviews for their time and effort. I would like to express my sincere appreciation to Professor E Garcia, Editor-in-Chief, for his encouragement by providing the opportunity to make this special section. I am indebted to IOP Publishing for their strong support and the staff, in particular publisher Natasha Leeper, for their special attention and excellent service.

Complete diagnostics of pyroactive structures for smart systems of optoelectronics

NASA Astrophysics Data System (ADS)

Bravina, Svetlana L.; Morozovsky, Nicholas V.

1998-04-01

The results of study of pyroelectric phenomena in ferroelectric materials for evidence of the possibility to embody the functions promising for creation of smart systems for optoelectronic applications are presented. Designing such systems requires the development of methods for non- destructive complete diagnostics preferably by developing the self-diagnostic ability inherent in materials with the features of smart/intelligent ones. The complex method of complete non-destructive qualification of pyroactive materials based on the method of dynamic photopyroelectric effect allows the determination of pyroelectric, piezoelectric, ferroelectric, dielectric and thermophysical characteristics. The measuring system which allows the study of these characteristics and also memory effects, switching effects, fatigue and degradation process, self-repair process and others is presented. Sample pyroactive system with increased intelligence, such as systems with built-in adaptive controllable domain structure promising for functional optics are developed and peculiarities of their characterization are discussed.

Innovative Materials for Aircraft Morphing

NASA Technical Reports Server (NTRS)

Simpson, J. O.; Wise, S. A.; Bryant, R. G.; Cano, R. J.; Gates, T. S.; Hinkley, J. A.; Rogowski, R. S.; Whitley, K. S.

1997-01-01

Reported herein is an overview of the research being conducted within the Materials Division at NASA Langley Research Center on the development of smart material technologies for advanced airframe systems. The research is a part of the Aircraft Morphing Program which is a new six-year research program to develop smart components for self-adaptive airframe systems. The fundamental areas of materials research within the program are computational materials; advanced piezoelectric materials; advanced fiber optic sensing techniques; and fabrication of integrated composite structures. This paper presents a portion of the ongoing research in each of these areas of materials research.

DARPA/AFRL/NASA Smart Wing Second Wind Tunnel Test Results

NASA Technical Reports Server (NTRS)

Scherer, L. B.; Martin, C. A.; West, M.; Florance, J. P.; Wieseman, C. D.; Burner, A. W.; Fleming, G. A.

2001-01-01

To quantify the benefits of smart materials and structures adaptive wing technology, Northrop Grumman Corp. (NGC) built and tested two 16% scale wind tunnel models (a conventional and a "smart" model) of a fighter/attack aircraft under the DARPA/AFRL/NASA Smart Materials and Structures Development - Smart Wing Phase 1. Performance gains quantified included increased pitching moment (C(sub M)), increased rolling moment (C(subl)) and improved pressure distribution. The benefits were obtained for hingeless, contoured trailing edge control surfaces with embedded shape memory alloy (SMA) wires and spanwise wing twist effected by SMA torque tube mechanisms, compared to conventional hinged control surfaces. This paper presents an overview of the results from the second wind tunnel test performed at the NASA Langley Research Center s (LaRC) 16ft Transonic Dynamic Tunnel (TDT) in June 1998. Successful results obtained were: 1) 5 degrees of spanwise twist and 8-12% increase in rolling moment utilizing a single SMA torque tube, 2) 12 degrees of deflection, and 10% increase in rolling moment due to hingeless, contoured aileron, and 3) demonstration of optical techniques for measuring spanwise twist and deflected shape.

Aeroservoelastic and Structural Dynamics Research on Smart Structures Conducted at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

McGowan, Anna-Maria Rivas; Wilkie, W. Keats; Moses, Robert W.; Lake, Renee C.; Florance, Jennifer Pinkerton; Wieseman, Carol D.; Reaves, Mercedes C.; Taleghani, Barmac K.; Mirick, Paul H.; Wilbur, Mathew L.

1997-01-01

An overview of smart structures research currently underway at the NASA Langley Research Center in the areas of aeroservoelasticity and structural dynamics is presented. Analytical and experimental results, plans, potential technology pay-offs, and challenges are discussed. The goal of this research is to develop the enabling technologies to actively and passively control aircraft and rotorcraft vibration and loads using smart devices. These enabling technologies and related research efforts include developing experimentally-validated finite element and aeroservoelastic modeling techniques; conducting bench experimental tests to assess feasibility and understand system trade-offs; and conducting large-scale wind tunnel tests to demonstrate system performance. The key aeroservoelastic applications of this research include: active twist control of rotor blades using interdigitated electrode piezoelectric composites and active control of flutter, and gust and buffeting responses using discrete piezoelectric patches. In addition, NASA Langley is an active participant in the DARPA/Air Force Research Laboratory/NASA/Northrop Grumman Smart Wing program which is assessing aerodynamic performance benefits using smart materials.

Switchable Materials for Smart Windows.

PubMed

Wang, Yang; Runnerstrom, Evan L; Milliron, Delia J

2016-06-07

This article reviews the basic principles of and recent developments in electrochromic, photochromic, and thermochromic materials for applications in smart windows. Compared with current static windows, smart windows can dynamically modulate the transmittance of solar irradiation based on weather conditions and personal preferences, thus simultaneously improving building energy efficiency and indoor human comfort. Although some smart windows are commercially available, their widespread implementation has not yet been realized. Recent advances in nanostructured materials provide new opportunities for next-generation smart window technology owing to their unique structure-property relations. Nanomaterials can provide enhanced coloration efficiency, faster switching kinetics, and longer lifetime. In addition, their compatibility with solution processing enables low-cost and high-throughput fabrication. This review also discusses the importance of dual-band modulation of visible and near-infrared (NIR) light, as nearly 50% of solar energy lies in the NIR region. Some latest results show that solution-processable nanostructured systems can selectively modulate the NIR light without affecting the visible transmittance, thus reducing energy consumption by air conditioning, heating, and artificial lighting.

Aeroservoelastic and Structural Dynamics Research on Smart Structures Conducted at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

McGowan, Anna-Maria Rivas; Wilkie, W. Keats; Moses, Robert W.; Lake, Renee C.; Florance, Jennifer Pinkerton; Wieseman, Carol D.; Reaves, Mercedes C.; Taleghani, Barmac K.; Mirick, Paul H.; Wilbur, Matthew L.

1998-01-01

An overview of smart structures research currently underway at the NASA Langley Research Center in the areas of aeroservoelasticity and structural dynamics is presented. Analytical and experimental results, plans, potential technology pay-offs, and challenges are discussed. The goal of this research is to develop the enabling technologies to actively and passively control aircraft and rotorcraft vibration and loads using smart devices. These enabling technologies and related research efforts include developing experimentally-validated finite element and aeroservoelastic modeling techniques; conducting bench experimental tests to assess feasibility and understand system trade-offs; and conducting large-scale wind- tunnel tests to demonstrate system performance. The key aeroservoelastic applications of this research include: active twist control of rotor blades using interdigitated electrode piezoelectric composites and active control of flutter, and gust and buffeting responses using discrete piezoelectric patches. In addition, NASA Langley is an active participant in the DARPA/ Air Force Research Laboratory/ NASA/ Northrop Grumman Smart Wing program which is assessing aerodynamic performance benefits using smart materials. Keywords: aeroelasticity, smart structures, piezoelectric actuators, active fiber composites, rotorcraft, buffet load alleviation, individual blade control, aeroservoelasticity, shape memory alloys, damping augmentation, piezoelectric power consumption

Functional and Multifunctional Polymers: Materials for Smart Structures

NASA Technical Reports Server (NTRS)

Arnold, S.; Pratt, L. M.; Li, J.; Wuagaman, M.; Khan, I. M.

1996-01-01

The ultimate goal of the research in smart structures and smart materials is the development of a new generation of products/devices which will perform better than products/devices built from passive materials. There are a few examples of multilayer polymer systems which function as smart structures, e.g. a synthetic muscle which is a multilayer assembly of a poly(ethylene) layer, a gold layer, and a poly(pyrrole) layer immersed in a liquid electrolyte. Oxidation and reductions of the active pyrrole layer causes the assembly to reversibly deflect and mimic biological muscles. The drawback of such a setup is slow response times and the use of a liquid electrolyte. We have developed multifunctional polymers which will eliminate the use of a liquid electrolyte, and also because the functionalities of the polymers are within a few hundred angstroms, an improved response time to changes in the external field should be possible. Such multifunctional polymers may be classified as the futuristic 'smart materials.' These materials are composed of a number of different functionalities which work in a synergistic fashion to function as a device. The device performs on the application of an external field and such multifunctional polymers may be scientifically labeled as 'field responsive polymers.' Our group has undertaken a systematic approach to develop functional and multifunctional polymers capable of functioning as field responsive polymers. Our approach utilizes multicomponent polymer systems (block copolymers and graft copolymers), the strategy involves the preparation of block or graft copolymers where the functionalities are limited to different phases in a microphase separated system. Depending on the weight (or volume) fractions of each of the components, different microstructures are possible. And, because of the intimate contact between the functional components, an increase in the synergism between the functionalities may be observed. In this presentation, three examples of multifunctional polymers developed in our labs will be reported. The first class of multifunctional polymers are the microphase separated mixed (ionic and electronic) conducting or MIEC block copolymers. The second class being developed in our labs are the biocompatible conductive materials and the conductive fluids. The final class may be considered microwave active smart polymers.

Overview of demonstrator program of Japanese Smart Materials and Structure System project

NASA Astrophysics Data System (ADS)

Tajima, Naoyuki; Sakurai, Tateo; Sasajima, Mikio; Takeda, Nobuo; Kishi, Teruo

2003-08-01

The Japanese Smart Material and Structure System Project started in 1998 as five years' program that funded by METI (Ministry of Economy, Trade and Industry) and supported by NEDO (New Energy and Industrial Technology Development Organization). Total budget of five years was finally about 3.8 billion Japanese yen. This project has been conducted as the Academic Institutions Centered Program, namely, one of collaborated research and development among seven universities (include one foreign university), seventeen Industries (include two foreign companies), and three national laboratories. At first, this project consisted of four research groups that were structural health monitoring, smart manufacturing, active/adaptive structures, and actuator material/devices. Two years later, we decided that two demonstrator programs should be added in order to integrate the developed sensor and actuator element into the smart structure system and verify the research and development results of above four research groups. The application target of these demonstrators was focused to the airplane, and two demonstrators that these shapes simulate to the fuselage of small commercial airplane (for example, Boeing B737) had been established. Both demonstrators are cylindrical structures with 1.5 m in diameter and 3 m in length that the first demonstrator has CFRP skin-stringer and the second one has CFRP skin. The first demonstrator integrates the following six innovative techniques: (1) impact monitoring using embedded small diameter optical fiber sensors newly developed in this program, (2) impact monitoring using the integrated acoustic emission (AE) systems, (3) whole-field strain mapping using the BOTDR/FBG integrated system, (4) damage suppression using embedded shape memory alloy (SMA) films, (5) maximum and cyclic strain sensing using smart composite patches, and (6) smart manufacturing using the integrated sensing system. The second one is for demonstrating the suppression of vibration and acoustic noise generated in the composite cylindrical structure. In this program, High-performance PZT actuators/sensors developed in this program are also installed. The whole tests and evaluations have now been finished. This paper presents the outline of demonstrator programs, followed by six presentations that show the detail verification results of industrial demonstration themes.

Nature-Inspired Structural Materials for Flexible Electronic Devices.

PubMed

Liu, Yaqing; He, Ke; Chen, Geng; Leow, Wan Ru; Chen, Xiaodong

2017-10-25

Exciting advancements have been made in the field of flexible electronic devices in the last two decades and will certainly lead to a revolution in peoples' lives in the future. However, because of the poor sustainability of the active materials in complex stress environments, new requirements have been adopted for the construction of flexible devices. Thus, hierarchical architectures in natural materials, which have developed various environment-adapted structures and materials through natural selection, can serve as guides to solve the limitations of materials and engineering techniques. This review covers the smart designs of structural materials inspired by natural materials and their utility in the construction of flexible devices. First, we summarize structural materials that accommodate mechanical deformations, which is the fundamental requirement for flexible devices to work properly in complex environments. Second, we discuss the functionalities of flexible devices induced by nature-inspired structural materials, including mechanical sensing, energy harvesting, physically interacting, and so on. Finally, we provide a perspective on newly developed structural materials and their potential applications in future flexible devices, as well as frontier strategies for biomimetic functions. These analyses and summaries are valuable for a systematic understanding of structural materials in electronic devices and will serve as inspirations for smart designs in flexible electronics.

Fabrication of Microcapsules for Dye-Doped Polymer-Dispersed Liquid Crystal-Based Smart Windows.

PubMed

Kim, Mingyun; Park, Kyun Joo; Seok, Seunghwan; Ok, Jong Min; Jung, Hee-Tae; Choe, Jaehoon; Kim, Do Hyun

2015-08-19

A dye-doped polymer-dispersed liquid crystal (PDLC) is an attractive material for application in smart windows. Smart windows using a PDLC can be operated simply and have a high contrast ratio compared to those of other devices that employed photochromic or thermochromic material. However, in conventional dye-doped PDLC methods, dye contamination can cause problems and has a limited degree of commercialization of electric smart windows. Here, we report on an approach to resolve dye-related problems by encapsulating the dye in monodispersed capsules. By encapsulation, a fabricated dye-doped PDLC had a contrast ratio of >120 at 600 nm. This fabrication method of encapsulating the dye in a core-shell structured microcapsule in a dye-doped PDLC device provides a practical platform for dye-doped PDLC-based smart windows.

Fiber-Optic Sensor And Smart Structures Research At Florida Institute Of Technology

NASA Astrophysics Data System (ADS)

Grossman, Barry G.; Alavie, A. Tino; Ham, Fredric M.; Franke, Jorge E.; Thursby, Michael H.

1990-02-01

This paper discusses the fundamental issues being investigated by Florida Institute of Technology (F.I.T.) to implement the technology of smart structural systems for DoD, NASA, and commercial applications. Embedded sensors and actuators controlled by processors can provide a modification of the mechanical characteristics of composite structures to produce smart structures1-3. Recent advances in material science have spurred the development and use of composite materials in a wide range of applications from rotocraft blades and advanced tactical fighter aircraft to undersea and aerospace structures. Along with the advantages of an increased strength-to-weight ratio, the use of these materials has raised a number of questions related to understanding their failure mechanisms. Also, being able to predict structural failures far enough in advance to prevent them and to provide real-time structural health and damage monitoring has become a realistic possibility. Unfortunately, conventional sensors, actuators, and digital processors, although highly developed and well proven for other systems, may not be best suited for most smart structure applications. Our research has concentrated on few-mode and polarimetric single-fiber strain sensors4-7 and optically activated shape memory alloy (SMA) actuators controlled by artificial neural processors. We have constructed and characterized both few-mode and polarimetric sensors for a variety of fiber types, including standard single-mode, high-birefringence polarization preserving, and low-birefringence polarization insensitive fibers. We have investigated signal processing techniques for these sensors and have demonstrated active phase tracking for the high- and low-birefringence polarimetric sensors through the incorporation into the system of an electrooptic modulator designed and fabricated at F.I.T.. We have also started the design and testing of neural network architectures for processing the sensor signal outputs to calculate strain magnitude and actuator control signals for simple structures.

SPIE Smart Structures Product Implementation Award: a review of the first ten years

NASA Astrophysics Data System (ADS)

Anderson, Eric H.; Sater, Janet M.

2007-04-01

The research field of smart materials and structures has been a distinct entity for two decades. Over the past ten years, the SPIE Industrial and Commercial Applications Conference has presented a Smart Structures Product Implementation Award at its annual symposium. This paper revisits the nine winning entries to date (1998-2007) and updates their status. The paper begins with a brief description of the original and current intent of the award and follows with a short overview of the evolution of smart structures, from research to products. The winning teams and their respective products are then described. The current status of the products is discussed based on publicly available information and input from the respective companies. Note however that it is not the purpose of the paper to rank the product winners in terms of success or sales. The paper concludes with an assessment of the larger trends in productization of smart structures technologies. The application "form" for the award as well as the evaluation criteria and suggestions for improving award application packages can be found in the appendix.

Noncontact power/interrogation system for smart structures

NASA Astrophysics Data System (ADS)

Spillman, William B., Jr.; Durkee, S.

1994-05-01

The field of smart structures has been largely driven by the development of new high performance designed materials. Use of these materials has been generally limited due to the fact that they have not been in use long enough for statistical data bases to be developed on their failure modes. Real time health monitoring is therefore required for the benefits of structures using these materials to be realized. In this paper a non-contact method of powering and interrogating embedded electronic and opto-electronic systems is described. The technique utilizes inductive coupling between external and embedded coils etched on thin electronic circuit cards. The technique can be utilized to interrogate embedded sensors and to provide > 250 mW for embedded electronics. The system has been successfully demonstrated with a number of composite and plastic materials through material thicknesses up to 1 cm. An analytical description of the system is provided along with experimental results.

Active Control Technology at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Antcliff, Richard R.; McGowan, Anna-Marie R.

2000-01-01

NASA Langley has a long history of attacking important technical Opportunities from a broad base of supporting disciplines. The research and development at Langley in this subject area range from the test tube to the test flight, The information covered here will range from the development of innovative new materials, sensors and actuators, to the incorporation of smart sensors and actuators in practical devices, to the optimization of the location of these devices, to, finally, a wide variety of applications of these devices utilizing Langley's facilities and expertise. Advanced materials are being developed for sensors and actuators, as well as polymers for integrating smart devices into composite structures. Contributions reside in three key areas: computational materials; advanced piezoelectric materials; and integrated composite structures.

Modeling Smart Structure of Wind Turbine Blade

NASA Astrophysics Data System (ADS)

Qiao, Yin-hu; Han, Jiang; Zhang, Chun-yan; Chen, Jie-ping

2012-06-01

With the increasing size of wind turbine blades, the need for more sophisticated load control techniques has induced the interest for aerodynamic control systems with build-in intelligence on the blades. The paper aims to provide a way for modeling the adaptive wind turbine blades and analyze its ability for vibration suppress. It consists of the modeling of the adaptive wind turbine blades with the wire of piezoelectric material embedded in blade matrix, and smart sandwich structure of wind turbine blade. By using this model, an active vibration method which effectively suppresses the vibrations of the smart blade is designed.

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation.

PubMed

Dini, Danilo; Calvete, Mário J F; Hanack, Michael

2016-11-23

The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.

Development and Application of a Structural Health Monitoring System Based on Wireless Smart Aggregates

PubMed Central

Ma, Haoyan; Li, Peng; Song, Gangbing; Wu, Jianxin

2017-01-01

Structural health monitoring (SHM) systems can improve the safety and reliability of structures, reduce maintenance costs, and extend service life. Research on concrete SHMs using piezoelectric-based smart aggregates have reached great achievements. However, the newly developed techniques have not been widely applied in practical engineering, largely due to the wiring problems associated with large-scale structural health monitoring. The cumbersome wiring requires much material and labor work, and more importantly, the associated maintenance work is also very heavy. Targeting a practical large scale concrete crack detection (CCD) application, a smart aggregates-based wireless sensor network system is proposed for the CCD application. The developed CCD system uses Zigbee 802.15.4 protocols, and is able to perform dynamic stress monitoring, structural impact capturing, and internal crack detection. The system has been experimentally validated, and the experimental results demonstrated the effectiveness of the proposed system. This work provides important support for practical CCD applications using wireless smart aggregates. PMID:28714927

Development and Application of a Structural Health Monitoring System Based on Wireless Smart Aggregates.

PubMed

Yan, Shi; Ma, Haoyan; Li, Peng; Song, Gangbing; Wu, Jianxin

2017-07-17

Structural health monitoring (SHM) systems can improve the safety and reliability of structures, reduce maintenance costs, and extend service life. Research on concrete SHMs using piezoelectric-based smart aggregates have reached great achievements. However, the newly developed techniques have not been widely applied in practical engineering, largely due to the wiring problems associated with large-scale structural health monitoring. The cumbersome wiring requires much material and labor work, and more importantly, the associated maintenance work is also very heavy. Targeting a practical large scale concrete crack detection (CCD) application, a smart aggregates-based wireless sensor network system is proposed for the CCD application. The developed CCD system uses Zigbee 802.15.4 protocols, and is able to perform dynamic stress monitoring, structural impact capturing, and internal crack detection. The system has been experimentally validated, and the experimental results demonstrated the effectiveness of the proposed system. This work provides important support for practical CCD applications using wireless smart aggregates.

Structural colored gels for tunable soft photonic crystals.

PubMed

Harun-Ur-Rashid, Mohammad; Seki, Takahiro; Takeoka, Yukikazu

2009-01-01

A periodically ordered interconnecting porous structure can be embodied in chemical gels by using closest-packed colloidal crystals as templates. The interconnecting porosity not only provides a quick response but also endows the porous gels with structural color arising from coherent Bragg optical diffraction. The structural colors revealed by porous gels can be regulated by several techniques, and thus, it is feasible to obtain desirable, smart, soft materials. A well-known thermosensitive monomer, N-isopropylacrylamide (NIPA), and other minor monomers were used to fabricate various structural colored gels. The selection of minor monomers depended on the targeted properties. This review focuses on the synthesis of templates, structural colored porous gels, and the applications of structural colored gel as smart soft materials for tunable photonic crystals. (c) 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Using smart materials to solve new challenges in the automotive industry

NASA Astrophysics Data System (ADS)

Gath, Kerrie K.; Maranville, Clay; Tardiff, Janice

2018-03-01

Ford has an extensive history of developing and utilizing smart and innovative materials in its vehicles. In this paper, we present new challenges the automotive industry is facing and explore how intelligent uses of smart materials can help provide solutions. We explore which vehicle attributes may provide most advantageous for the use smart materials, and discuss how smart material have had technical challenges that limit their use. We also look at how smart materials such as gecko inspired adhesion is providing opportunities during the vehicle assembly process by improving manufacturing quality, environmental sustainability, and worker safety. An emerging area for deployment of smart materials may involve autonomous vehicles and mobility solutions, where customer expectations are migrating toward a seamless and adaptive experience leading to new expectations for an enhanced journey. Another area where smart materials are influencing change is interior and exterior design including smart textiles, photochromatic dyes, and thermochromatic materials. The key to advancing smart materials in automotive industry is to capitalize on the smaller niche applications where there will be an advantage over traditional methods. Ford has an extensive history of developing and utilizing smart and innovative materials. Magnetorheological fluids, thermoelectric materials, piezoelectric actuators, and shape memory alloys are all in production. In this paper we present new challenges the automotive industry is facing and explore how intelligent uses of smart materials can help provide solutions. We explore which vehicle attributes may provide most advantageous for the use smart materials, and discuss how smart materials have had technical challenges that limit their use. An emerging area for deployment of smart materials may involve autonomous vehicles and mobility solutions, where customer expectations may require a seamless and adaptive experience for users having various expectations.

Triboluminescent Materials for Smart Optical Damage Sensors for Space Applications

NASA Technical Reports Server (NTRS)

Aggarwal, M. D.; Penn, B. G.; Miller, J.; Sadate, S.; Batra, A. K.

2008-01-01

There is a need to develop a new technique of damage detection for composites, which could detect cracking or delamination from any desired location within a material structure in real time. Recently, triboluminescent materials have been proposed as smart sensors of structural damage. To sense the damage, these materials can be epoxy bonded, coated in a polymer matrix, or embedded in a composite host structure. When the damage or fracture takes place in the host structure, the resultant fracture of triboluminescent crystals creates a light emission. This will warn in real time that structural damage has occurred. The triboluminescent emission of the candidate phosphor has to be bright enough that the light reaching from the point of fracture to the detector through a fiber optic cable is detectable. There are a large number of triboluminescent materials, but few satisfy the above criterion. The authors have synthesized an organic material known as Europium tetrakis (dibenzoylmethide) triethylammonium (EuD4TEA), which is a potential candidate for application as a damage sensor and could be made into a wireless sensor with the addition of microchip, antenna, and electronics. Preliminary results on the synthesis and characterization of this material are presented.

Elastic memory composites (EMC) for deployable industrial and commercial applications

NASA Astrophysics Data System (ADS)

Arzberger, Steven C.; Tupper, Michael L.; Lake, Mark S.; Barrett, Rory; Mallick, Kaushik; Hazelton, Craig; Francis, William; Keller, Phillip N.; Campbell, Douglas; Feucht, Sara; Codell, Dana; Wintergerst, Joe; Adams, Larry; Mallioux, Joe; Denis, Rob; White, Karen; Long, Mark; Munshi, Naseem A.; Gall, Ken

2005-05-01

The use of smart materials and multifunctional components has the potential to provide enhanced performance, improved economics, and reduced safety concerns for applications ranging from outer space to subterranean. Elastic Memory Composite (EMC) materials, based on shape memory polymers and used to produce multifunctional components and structures, are being developed and qualified for commercial use as deployable components and structures. EMC materials are similar to traditional fiber-reinforced composites except for the use of a thermoset shape memory resin that enables much higher packaging strains than traditional composites without damage to the fibers or the resin. This unique capability is being exploited in the development of very efficient EMC structural components for deployable spacecraft systems as well as capability enhancing components for use in other industries. The present paper is intended primarily to describe the transition of EMC materials as smart structure technologies into viable industrial and commercial products. Specifically, the paper discusses: 1) TEMBO EMC materials for deployable space/aerospace systems, 2) TEMBO EMC resins for terrestrial applications, 3) future generation EMC materials.

Smart bricks for strain sensing and crack detection in masonry structures

NASA Astrophysics Data System (ADS)

Downey, Austin; D'Alessandro, Antonella; Laflamme, Simon; Ubertini, Filippo

2018-01-01

The paper proposes the novel concept of smart bricks as a durable sensing solution for structural health monitoring of masonry structures. The term smart bricks denotes piezoresistive clay bricks with suitable electronics capable of outputting measurable changes in their electrical properties under changes in their state of strain. This feature can be exploited to evaluate stress at critical locations inside a masonry wall and to detect changes in loading paths associated with structural damage, for instance following an earthquake. Results from an experimental campaign show that normal clay bricks, fabricated in the laboratory with embedded electrodes made of a special steel for resisting the high baking temperature, exhibit a quite linear and repeatable piezoresistive behavior. That is a change in electrical resistance proportional to a change in axial strain. In order to be able to exploit this feature for strain sensing, high-resolution electronics are used with a biphasic DC measurement approach to eliminate any resistance drift due to material polarization. Then, an enhanced nanocomposite smart brick is proposed, where titania is mixed with clay before baking, in order to enhance the brick’s mechanical properties, improve its noise rejection, and increase its electrical conductivity. Titania was selected among other possible conductive nanofillers due to its resistance to high temperatures and its ability to improve the durability of construction materials while maintaining the aesthetic appearance of clay bricks. An application of smart bricks for crack detection in masonry walls is demonstrated by laboratory testing of a small-scale wall specimen under different loading conditions and controlled damage. Overall, it is demonstrated that a few strategically placed smart bricks enable monitoring of the state of strain within the wall and provide information that is capable of crack detection.

Multi-Scale Sizing of Lightweight Multifunctional Spacecraft Structural Components

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.

2005-01-01

This document is the final report for the project entitled, "Multi-Scale Sizing of Lightweight Multifunctional Spacecraft Structural Components," funded under the NRA entitled "Cross-Enterprise Technology Development Program" issued by the NASA Office of Space Science in 2000. The project was funded in 2001, and spanned a four year period from March, 2001 to February, 2005. Through enhancements to and synthesis of unique, state of the art structural mechanics and micromechanics analysis software, a new multi-scale tool has been developed that enables design, analysis, and sizing of advance lightweight composite and smart materials and structures from the full vehicle, to the stiffened structure, to the micro (fiber and matrix) scales. The new software tool has broad, cross-cutting value to current and future NASA missions that will rely on advanced composite and smart materials and structures.

Dynamic stress compensation by smart actuation

NASA Astrophysics Data System (ADS)

Irschik, Hans; Gusenbauer, Markus; Pichler, Uwe

2004-07-01

The actuating physical mechanisms utilized in smart materials can be described by eigenstrains. E.g., the converse piezoelectric effect in a piezoelastic body may be understood as an actuating eigenstrain. In the last decades, piezoelectricity has been extensively applied for the sake of actuation and sensing of structural vibrations. An important field of research in this respect has been devoted to the goal of compensating force-induced vibrations by means of eigenstrains. Considering the state-of-the-art in structural control and smart materials, almost no research has been performed on the problem of compensating stresses in force-loaded engineering structures by eigenstrains. It is well-known that stresses can influence the characteristics and the age of structures in various unpleasant ways. The present contribution is concerned with corresponding concepts for stress compensation which may have a highly beneficial influence upon the lifetime and structural integrity of the structure under consideration. We discuss the possibilities offered by displacement compensation to reduce the stresses to their quasi-static parts. As a numerical example, we consider the step response of an irregularly shaped cantilevered elastic plate under the action of an assigned traction at its boundary.

Smart and functional polymer materials for smart and functional microfluidic instruments

NASA Astrophysics Data System (ADS)

Gray, Bonnie L.

2014-04-01

As microfluidic systems evolve from "chip-in-the-lab" to true portable lab-on-a-chip (LoC) or lab-in-a-package (LiP) microinstrumentation, there is a need for increasingly miniaturized sensors, actuators, and integration/interconnect technologies with high levels of functionality and self-direction. Furthermore, as microfluidic instruments are increasingly realized in polymer-based rather than glass- or silicon- based platforms, there is a need to realize these highly functional components in materials that are polymer-compatible. Polymers that are altered to possess basic functionality, and even higher-functioning "smart" polymer materials, may help to realize high-functioning and selfdirecting portable microinstrumentation. Stimuli-responsive hydrogels have been recognized for over a decade as beneficial to the development of smart microfluidics systems and instrumentation. In addition, functional materials such as conductive and magnetic composite polymers are being increasingly employed to push microfluidics systems to greater degrees of functionality, portability, and/or flexibility for wearable/implantable systems. Functional and smart polymer materials can be employed to realize electrodes, electronic routing, heaters, mixers, valves, pumps, sensors, and interconnect structures in polymer-based microfluidic systems. Stimuli for such materials can be located on-chip or in a small package, thus greatly increasing the degree of portability and the potential for mechanical flexibility of such systems. This paper will examine the application of functional polymer materials to the development of high-functioning microfluidics instruments with a goal towards self-direction.

DARPA/ARFL/NASA Smart Wing second wind tunnel test results

NASA Astrophysics Data System (ADS)

Scherer, Lewis B.; Martin, Christopher A.; West, Mark N.; Florance, Jennifer P.; Wieseman, Carol D.; Burner, Alpheus W.; Fleming, Gary A.

1999-07-01

To quantify the benefits of smart materials and structures adaptive wing technology. Northrop Grumman Corp. built and tested two 16 percent scale wind tunnel models of a fighter/attach aircraft under the DARPA/AFRL/NASA Smart Materials and Structures Development - Smart Wing Phase 1. Performance gains quantified included increased pitching moment, increased rolling moment and improved pressure distribution. The benefits were obtained for hingeless, contoured trailing edge control surfaces with embedded shape memory alloy wires and spanwise wing twist effected by SMA torque tube mechanism, compared to convention hinged control surfaces. This paper presents an overview of the results from the second wind tunnel test performed at the NASA Langley Research Center's 16 ft Transonic Dynamic Tunnel in June 1998. Successful results obtained were: 1) 5 degrees of spanwise twist and 8-12 percent increase in rolling moment utilizing a single SMA torque tube, 2) 12 degrees of deflection, and 10 percent increase in rolling moment due to hingeless, contoured aileron, and 3) demonstration of optical techniques for measuring spanwise twist and deflected shape.

Encyclopedia of Smart Materials, 2 Volume Set

NASA Astrophysics Data System (ADS)

Schwartz, Mel

2002-03-01

Smart materials--materials and structures that can impart information about their environment to an observer or monitoring device--are revolutionizing fields as diverse as engineering, optics, and medical technology. Advances in smart materials are impacting disciplines across the scientific and technological landscape. Now, practictioners and researchers have an authoritative source to go to for answers about this emerging new area. Encyclopedia of Smart Materials provides A-to-Z coverage of the entire field of intelligent materials. Discussions of theory, fabrication, processing, applications, and uses of these unique materials are presented here in a collection of concise entries from the world's foremost experts in the field--including scientists, educators and engineers. This encyclopedia is as broad in scope as the technology itself, addressing daily, commercial applications as well as sophisticated units designed to operate in space, underwater, underground, and within the human body. Extensively cross-referenced and generously supplemented with bibliographies and indexes, this book's treatment also broaches the specialized properties and coatings that are required for the use of materials in extreme conditions. Illustrated with photographs, tables, line drawings, and equations, Encyclopedia of Smart Materials is the premier reference for material scientists, chemists, chemical engineers, process engineers, consultants, patent attorneys and students in these areas. An essential resource on the shelves of laboratories, government facilities, and academic libraries. Editor-in-Chief, Mel Schwartz has over forty years of experience with metals, ceramics, and composites, with special expertise in brazing. The holder of five patents, he has authored thirteen books and more than one hundred technical papers and articles. Reach the information you need rapidly and easily with the ONLINE edition of the Encyclopedia of Smart Materials. The online edition delivers all the rich content of the print edition with the added benefits of an advanced search engine and the desktop convenience of web access. For more information or to license the online edition (beginning July 2002) please visit: www.interscience.wiley.com/reference/esm

Multifunctional smart composites with integrated carbon nanotube yarn and sheet

NASA Astrophysics Data System (ADS)

Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

2017-04-01

Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

Smart material screening machines using smart materials and controls

NASA Astrophysics Data System (ADS)

Allaei, Daryoush; Corradi, Gary; Waigand, Al

2002-07-01

The objective of this product is to address the specific need for improvements in the efficiency and effectiveness in physical separation technologies in the screening areas. Currently, the mining industry uses approximately 33 billion kW-hr per year, costing 1.65 billion dollars at 0.05 cents per kW-hr, of electrical energy for physical separations. Even though screening and size separations are not the single most energy intensive process in the mining industry, they are often the major bottleneck in the whole process. Improvements to this area offer tremendous potential in both energy savings and production improvements. Additionally, the vibrating screens used in the mining processing plants are the most costly areas from maintenance and worker health and safety point of views. The goal of this product is to reduce energy use in the screening and total processing areas. This goal is accomplished by developing an innovative screening machine based on smart materials and smart actuators, namely smart screen that uses advanced sensory system to continuously monitor the screening process and make appropriate adjustments to improve production. The theory behind the development of Smart Screen technology is based on two key technologies, namely smart actuators and smart Energy Flow ControlT (EFCT) strategies, developed initially for military applications. Smart Screen technology controls the flow of vibration energy and confines it to the screen rather than shaking much of the mass that makes up the conventional vibratory screening machine. Consequently, Smart Screens eliminates and downsizes many of the structural components associated with conventional vibratory screening machines. As a result, the surface area of the screen increases for a given envelope. This increase in usable screening surface area extends the life of the screens, reduces required maintenance by reducing the frequency of screen change-outs and improves throughput or productivity.

Choice of rational structural solution for smart innovative suspension structure

NASA Astrophysics Data System (ADS)

Goremikins, V.; Serdjuks, D.; Buka-Vaivade, K.; Pakrastins, L.

2017-10-01

Choice of the rational structural solution for smart innovative suspension structure was carried out. The prestressed cable trusses and cross-laminated timber panels were considered as the main load bearing members for the smart innovative suspension structure. The FEM model, which enables to predict behaviours of the structure, was developed in the programme ANSYS v12. Structural solutions that are differed by the lattice configuration of the cable truss and placement of cross-laminated timber panels were considered. The variant of the cable truss with the vertical suspenders and chords joined in the middle of the span was chosen as the best one. It was shown, that placement of cross-laminated timber panels by the bottom chord of the prestressed cable truss enables to decrease materials consumption by 16.7% in comparison with the variant, where the panels are placed by the top chord. It was stated, that the materials consumption decrease by 17.3% in the case, when common work of the prestressed cable trusses and cross-laminated timber panels is taken into account. The cross-laminated timber panels are working in the both directions. Physical model of the structure with the span equal to 2 m was developed for checking of numerically obtained results.

Probabilistic Dynamic Buckling of Smart Composite Shells

NASA Technical Reports Server (NTRS)

Abumeri, Galib H.; Chamis, Christos C.

2003-01-01

A computational simulation method is presented to evaluate the deterministic and nondeterministic dynamic buckling of smart composite shells. The combined use of composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right below the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 10 percent at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load while uncertainties in the electric field strength and smart material volume fraction have moderate effects. For the specific shell considered in this evaluation, the use of smart composite material is not recommended because the shell buckling resistance can be improved by simply re-arranging the orientation of the outer plies, as shown in the dynamic buckling analysis results presented in this report.

Probabilistic Dynamic Buckling of Smart Composite Shells

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2007-01-01

A computational simulation method is presented to evaluate the deterministic and nondeterministic dynamic buckling of smart composite shells. The combined use of intraply hybrid composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right next to the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 10% at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load while uncertainties in the electric field strength and smart material volume fraction have moderate effects. For the specific shell considered in this evaluation, the use of smart composite material is not recommended because the shell buckling resistance can be improved by simply re-arranging the orientation of the outer plies, as shown in the dynamic buckling analysis results presented in this report.

Smart hybrid rotary damper

NASA Astrophysics Data System (ADS)

Yang, C. S. Walter; DesRoches, Reginald

2014-03-01

This paper develops a smart hybrid rotary damper using a re-centering smart shape memory alloy (SMA) material as well as conventional energy-dissipating metallic plates that are easy to be replaced. The ends of the SMA and steel plates are inserted in the hinge. When the damper rotates, all the plates bend, providing energy dissipating and recentering characteristics. Such smart hybrid rotary dampers can be installed in structures to mitigate structural responses and to re-center automatically. The damaged energy-dissipating plates can be easily replaced promptly after an external excitation, reducing repair time and costs. An OpenSEES model of a smart hybrid rotary was established and calibrated to reproduce the realistic behavior measured from a full-scale experimental test. Furthermore, the seismic performance of a 3-story moment resisting model building with smart hybrid rotary dampers designed for downtown Los Angeles was also evaluated in the OpenSEES structural analysis software. Such a smart moment resisting frame exhibits perfect residual roof displacement, 0.006", extremely smaller than 18.04" for the conventional moment resisting frame subjected to a 2500 year return period ground motion for the downtown LA area (an amplified factor of 1.15 on Kobe earthquake). The smart hybrid rotary dampers are also applied into an eccentric braced steel frame, which combines a moment frame system and a bracing system. The results illustrate that adding smart hybrid rotaries in this braced system not only completely restores the building after an external excitation, but also significantly reduces peak interstory drifts.

Automating the application of smart materials for protein crystallization.

PubMed

Khurshid, Sahir; Govada, Lata; El-Sharif, Hazim F; Reddy, Subrayal M; Chayen, Naomi E

2015-03-01

The fabrication and validation of the first semi-liquid nonprotein nucleating agent to be administered automatically to crystallization trials is reported. This research builds upon prior demonstration of the suitability of molecularly imprinted polymers (MIPs; known as `smart materials') for inducing protein crystal growth. Modified MIPs of altered texture suitable for high-throughput trials are demonstrated to improve crystal quality and to increase the probability of success when screening for suitable crystallization conditions. The application of these materials is simple, time-efficient and will provide a potent tool for structural biologists embarking on crystallization trials.

Nano-Bio Quantum Technology for Device-Specific Materials

NASA Technical Reports Server (NTRS)

Choi, Sang H.

2009-01-01

The areas discussed are still under development: I. Nano structured materials for TE applications a) SiGe and Be.Te; b) Nano particles and nanoshells. II. Quantum technology for optical devices: a) Quantum apertures; b) Smart optical materials; c) Micro spectrometer. III. Bio-template oriented materials: a) Bionanobattery; b) Bio-fuel cells; c) Energetic materials.

Detection of Non-Symmetrical Damage in Smart Plate-Like Structures

NASA Technical Reports Server (NTRS)

Blanks, H. T.; Emeric, P. R.

1998-01-01

A two-dimensional model for in-plane vibrations of a cantilever plate with a non-symmetrical damage is used in the context of defect identification in materials with piezoelectric ceramic patches bonded to their surface. These patches can act both as actuators and sensors in a self-analyzing fashion, which is a characteristic of smart materials. A Galerkin method is used to approximate the dynamic response of these structures. The natural frequency shifts due to the damage are estimated numerically and compared to experimental data obtained from tests on cantilever aluminum plate-like structures damaged at different locations with defects of different depths. The damage location and extent are determined by an enhanced least square identification method. Efficacy of the frequency shift based algorithms is demonstrated using experimental data.

Curved Thermopiezoelectric Shell Structures Modeled by Finite Element Analysis

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun

2000-01-01

"Smart" structures composed of piezoelectric materials may significantly improve the performance of aeropropulsion systems through a variety of vibration, noise, and shape-control applications. The development of analytical models for piezoelectric smart structures is an ongoing, in-house activity at the NASA Glenn Research Center at Lewis Field focused toward the experimental characterization of these materials. Research efforts have been directed toward developing analytical models that account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. Current work revolves around implementing thermal effects into a curvilinear-shell finite element code. This enhances capabilities to analyze curved structures and to account for coupling effects arising from thermal effects and the curved geometry. The current analytical model implements a unique mixed multi-field laminate theory to improve computational efficiency without sacrificing accuracy. The mechanics can model both the sensory and active behavior of piezoelectric composite shell structures. Finite element equations are being implemented for an eight-node curvilinear shell element, and numerical studies are being conducted to demonstrate capabilities to model the response of curved piezoelectric composite structures (see the figure).

Development and application of induced-strain actuators for building structures

NASA Astrophysics Data System (ADS)

Morita, Koichi; Fujita, Takafumi; Ise, Shiro; Kawaguchi, Ken-ichi; Kamada, Takayoshi; Fujitani, Hideo

2001-07-01

Induced strain actuator (ISA) can change their own shapes according to external electric/magnetic fields, and vice versa. Recently these materials have been widely used for the small/precision. The objectives in this study are to develop smart members for building and to realize the smart, comfortable and safe structures. The research items are 1) Semi-active isolation of structures using piezoelectric actuator, 2) Using ISA as sensor materials and 3) Improvement of Acoustic Environment. Semi-active base isolation system with controllable friction damper using piezoelectric actuators is proposed. Simulation study was carried out, and by semi-active isolation, it could be realized to reduce response displacement of the structure to 50% of values of the passive isolation. ISA materials can act as sensors because they cause change of electric or magnetic fields under deformation. PVDF sensors are suitable for membrane structures. We evaluate performance of PVDF sensors for membrane structures by experiment. Polymer based ISA films or distributed ISA devices can control vibration mode of plane members. Applications to music halls or dwelling partition walls are expected. Results of experimental studies of noise control are discussed.

Carbon nanotube based hybrid nanostructures: Synthesis and applications

NASA Astrophysics Data System (ADS)

Ou, Fung Suong

Hybrid nanostructures are fascinating materials for their promising applications in future nanoelectronics, electrical interconnects and energy storage devices. Practical ways of connecting individual carbon nanotubes to metal contacts for their use as interconnects and in electronic devices have been challenging. In this thesis, carbon nanotube based hybrids that combine the best properties of carbon nanotubes and metal nanowires have been fabricated. The electrical properties and Raman spectra of the hybrid nanowires are also studied. This thesis will focus on our recent results in the development of carbon nanotube hybrids for various applications. Various hybrid structures of multiwalled carbon nanotubes and metal nanowires can be fabricated using a combination of electrodeposition and chemical vapor deposition techniques. Controlled fabrication of multi-segmented structures will be studied. Several novel applications of these structures, for example, as electrodes in ultra-high power supercapacitors, multi-functional smart materials are also studied. The thesis will also highlight the development of carbon nanotube hybrids based smart materials. Hybrid nanowires with hydrophobic carbon nanotube tails and hydrophilic metal nanowire heads, allows for the assembly of spheres in solution. The design and manipulation of these carbon nanotube hybrids based smart structures for various novel applications will be discussed. Such new class of carbon nanotube hybrids surfactants are likely to lead as new tools in various fields such as microfluidics or water purification. In addition, we will also look at other variations of hybrid nanostructures fabricated from our method.

Sunlight-driven eco-friendly smart curtain based on infrared responsive graphene oxide-polymer photoactuators.

PubMed

Leeladhar; Raturi, Parul; Singh, J P

2018-02-27

Photomechanical actuation is the conversion of light energy into mechanical energy through some smart materials. Infrared-responsive smart materials have become an emerging field of research due to easy availability and eco-friendly nature of their stimulus in the form of sunlight, which contains about 50% of near-infrared(nIR) making these materials useful at macro-scale photoactuator applications. Here, we demonstrate fabrication of highly versatile nIR triggered photoactuators based on graphene oxide/polycarbonate bilayers that offers fast, low-cost fabrication, large deflection, reversible actuation and wavelength-selective response. The photoactuators are realized by vacuum filtration of graphene oxide/water dispersion through polycarbonate membrane resulting graphene oxide/polymer bilayer structure. The photoactuation response was measured in the form of deflection from equilibrium position as a result of infrared-irradiation. The deflection is caused by the generated thermal stress at the interface of bilayers due to mismatch of thermal expansion coefficient as a results of nIR absorption by graphene oxide and subsequent temperature rise. A maximum deflection of 12 mm (circular-shaped structure with diameter 28 mm) with corresponding bending curvature of 0.33 cm -1 was shown by this photoactuator for illumination intensity of 106 mW/cm 2 . Few applications of these photoactuators such as sunlight-driven smart curtain, infrared actuated curtain and self-folding box are also demonstrated.

Smart wormlike micelles.

PubMed

Chu, Zonglin; Dreiss, Cécile A; Feng, Yujun

2013-09-07

A major scientific challenge of the past decade pertaining to the field of soft matter has been to craft 'adaptable' materials, inspired by nature, which can dynamically alter their structure and functionality on demand, in response to triggers produced by environmental changes. Amongst these, 'smart' surfactant wormlike micelles, responsive to external stimuli, are a particularly recent area of development, yet highly promising, given the versatility of the materials but simplicity of the design-relying on small amphiphilic molecules and their spontaneous self-assembly. The switching 'on' and 'off' of the micellar assembly structures has been reported using electrical, optical, thermal or pH triggers and is now envisaged for multiple stimuli. The structural changes, in turn, can induce major variations in the macroscopic characteristics, affecting properties such as viscosity and elasticity and sometimes even leading to a spontaneous and effective 'sol-gel' transition. These original smart materials based on wormlike micelles have been successfully used in the oil industry, and offer a significant potential in a wide range of other technological applications, including biomedicine, cleaning processes, drag reduction, template synthesis, to name but a few. This review will report results in this field published over the last few years, describe the potential and practical applications of stimuli-responsive wormlike micelles and point out future challenges.

Impact analysis of automotive structures with distributed smart material systems

NASA Astrophysics Data System (ADS)

Peelamedu, Saravanan M.; Naganathan, Ganapathy; Buckley, Stephen J.

1999-06-01

New class of automobiles has structural skins that are quite different from their current designs. Particularly, new families of composite skins are developed with new injection molding processes. These skins while support the concept of lighter vehicles of the future, are also susceptible to damage upon impact. It is important that their design should be based on a better understanding on the type of impact loads and the resulting strains and damage. It is possible that these skins can be integrally designed with active materials to counter damages. This paper presents a preliminary analysis of a new class of automotive skins, using piezoceramic as a smart material. The main objective is to consider the complex system with, the skin to be modeled as a layered plate structure involving a lightweight material with foam and active materials imbedded on them. To begin with a cantilever beam structure is subjected to a load through piezoceramic and the resulting strain at the active material site is predicted accounting for the material properties, piezoceramic thickness, adhesive thickness including the effect of adhesives. A finite element analysis is carried out to compare experimental work. Further work in this direction would provide an analytical tool that will provide the basis for algorithms to predict and counter impacts on the future class of automobiles.

Experimental investigation of nonlinear characteristics of a smart fluid damper

NASA Astrophysics Data System (ADS)

Rahman, Mahmudur; Ong, Zhi Chao; Chong, Wen Tong; Julai, Sabariah; Ahamed, Raju

2018-05-01

Smart fluids, known as smart material, are used to form controllable dampers in vibration control applications. Magnetorheological(MR) fluid damper is a well-known smart fluid damper which has a reputation to provide high damping force with low-power input. However, the force/velocity of the MR damper is significantly nonlinear and proper characteristic analysis are required to be studied for optimal implementation in structural vibration control. In this study, an experimental investigation is carried out to test the damping characteristics of MR damper. Dynamic testing is performed with a long-stroke MR damper model no RD-80410-1 from Lord corporation on a universal testing machine(UTM). The force responses of MR damper are measured under different stroke lengths, velocities and current inputs and their performances are analyzed. This study will play a key role to implement MR damper in many structural vibration control applications.

Miniature vibration isolation system for space applications

NASA Astrophysics Data System (ADS)

Quenon, Dan; Boyd, Jim; Buchele, Paul; Self, Rick; Davis, Torey; Hintz, Timothy L.; Jacobs, Jack H.

2001-06-01

In recent years, there has been a significant interest in, and move towards using highly sensitive, precision payloads on space vehicles. In order to perform tasks such as communicating at extremely high data rates between satellites using laser cross-links, or searching for new planets in distant solar systems using sparse aperture optical elements, a satellite bus and its payload must remain relatively motionless. The ability to hold a precision payload steady is complicated by disturbances from reaction wheels, control moment gyroscopes, solar array drives, stepper motors, and other devices. Because every satellite is essentially unique in its construction, isolating or damping unwanted vibrations usually requires a robust system over a wide bandwidth. The disadvantage of these systems is that they typically are not retrofittable and not tunable to changes in payload size or inertias. Previous work, funded by AFRL, DARPA, BMDO and others, developed technology building blocks that provide new methods to control vibrations of spacecraft. The technology of smart materials enables an unprecedented level of integration of sensors, actuators, and structures; this integration provides the opportunity for new structural designs that can adaptively influence their surrounding environment. To date, several demonstrations have been conducted to mature these technologies. Making use of recent advances in smart materials, microelectronics, Micro-Electro Mechanical Systems (MEMS) sensors, and Multi-Functional Structures (MFS), the Air Force Research Laboratory along with its partner DARPA, have initiated an aggressive program to develop a Miniature Vibration Isolation System (MVIS) (patent pending) for space applications. The MVIS program is a systems-level demonstration of the application of advanced smart materials and structures technology that will enable programmable and retrofittable vibration control of spacecraft precision payloads. The current effort has been awarded to Honeywell Space Systems Operation. AFRL is providing in-house research and testing in support of the program as well. The MVIS program will culminate in a flight demonstration that shows the benefits of applying smart materials for vibration isolation in space and precision payload control.

Structural Integration of Sensors/Actuators by Laser Beam Melting for Tailored Smart Components

NASA Astrophysics Data System (ADS)

Töppel, Thomas; Lausch, Holger; Brand, Michael; Hensel, Eric; Arnold, Michael; Rotsch, Christian

2018-03-01

Laser beam melting (LBM), an additive laser powder bed fusion technology, enables the structural integration of temperature-sensitive sensors and actuators in complex monolithic metallic structures. The objective is to embed a functional component inside a metal part without losing its functionality by overheating. The first part of this paper addresses the development of a new process chain for bonded embedding of temperature-sensitive sensor/actuator systems by LBM. These systems are modularly built and coated by a multi-material/multi-layer thermal protection system of ceramic and metallic compounds. The characteristic of low global heat input in LBM is utilized for the functional embedding. In the second part, the specific functional design and optimization for tailored smart components with embedded functionalities are addressed. Numerical and experimental validated results are demonstrated on a smart femoral hip stem.

Load Diffusion in Composite and Smart Structures

NASA Technical Reports Server (NTRS)

Horgan, Cornelius O.; Ambur, D. (Technical Monitor); Nemeth, M. P. (Technical Monitor)

2003-01-01

The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for the multi-functional large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Some specific problems recently considered were those of end effects in smart materials and structures, study of the stress response of pressurized linear piezoelectric cylinders for both static and steady rotating configurations, an analysis of the effect of pre-stressing and pre-polarization on the decay of end effects in piezoelectric solids and investigation of constitutive models for hardening rubber-like materials. Our goal in the study of load diffusion is the development of readily applicable results for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses.

Wood as inspiration for new stimuli-responsive structures and materials

Treesearch

Joseph E. Jakes; Nayomi Plaza-Rodriguez; Samuel L. Zelinka; Donald S. Stone; Sophie-Charlotte Gleber; Stefan Vogt

2014-01-01

Nature has often provided inspiration for new smart structures and materials. Recently, we showed a bundle of a few wood cells are moisture-activated torsional actuators that can reversibly twist multiple revolutions per centimeter of length. The bundles produce specific torque higher than that produced by electric motors and possess shape memory twist capabilities....

Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures

PubMed Central

Cho, Keunhee; Park, Sung Yong; Cho, Jeong-Rae; Kim, Sung Tae; Park, Young-Hwan

2015-01-01

Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands. PMID:26083230

Structures Technology for Future Aerospace Systems

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Venneri, Samuel L.; Paul, Donald B.; Hopkins, Mark A.

2000-01-01

An overview of structures technology for future aerospace systems is given. Discussion focuses on developments in component technologies that will improve the vehicle performance, advance the technology exploitation process, and reduce system life-cycle costs. The component technologies described are smart materials and structures, multifunctional materials and structures, affordable composite structures, extreme environment structures, flexible load bearing structures, and computational methods and simulation-based design. The trends in each of the component technologies are discussed and the applicability of these technologies to future aerospace vehicles is described.

Changes in Structural Health Monitoring System Capability Due to Aircraft Environmental Factors

DTIC Science & Technology

2009-09-01

and R. Ikegami . “Hot-Spot Fatigue Crack Monitoring of Inaccessible Structural Regions in Air- craft Subsystems Using Structural Health Monitoring...national Society for Optical Engineering, volume 4702 of Smart Structures and Materials 2002, 29–40. Newport Beach, CA: SPIE, 2002. 54. Ikegami , R

The Science of Smart Materials

ERIC Educational Resources Information Center

Boohan, Richard

2011-01-01

Over the last few decades, smart materials have become increasingly important in the design of products. Essentially, a smart material is one that has been designed to respond to a stimulus, such as a change in temperature or magnetic field, in a particular and useful way. This article looks at a range of smart materials that are relatively…

Power systems and requirements for the integration of smart structures into aircraft

NASA Astrophysics Data System (ADS)

Lockyer, Allen J.; Martin, Christopher A.; Lindner, Douglas K.; Walia, Paramjit S.

2002-07-01

Electrical power distribution for recently developed smart actuators becomes an important air-vehicle challenge if projected smart actuation benefits are to be met. Among the items under development are variable shape inlets and control surfaces that utilize shape memory alloys (SMA); full span, chord-wise and span-wise contouring trailing control surfaces that use SMA or piezoelectric materials for actuation; and other strain-based actuators for buffet load alleviation, flutter suppression and flow control. At first glance, such technologies afford overall vehicle performance improvement, however, integration system impacts have yet to be determined or quantified. Power systems to support smart structures initiatives are the focus of the current paper. The paper has been organized into five main topics for further discussion: (1) air-vehicle power system architectures - standard and advanced distribution concepts for actuators, (2) smart wing actuator power requirements and results - highlighting wind tunnel power measurements from shape memory alloy and piezoelectric ultrasonic motor actuated control surfaces and different dynamic pressure and angle of attack; (3) vehicle electromagnetic effects (EME) issues, (4) power supply design considerations for smart actuators - featuring the aircraft power and actuator interface, and (5) summary and conclusions.

Piezoelectric assisted smart satellite structure (PEASSS): an innovative low cost nano-satellite

NASA Astrophysics Data System (ADS)

Rockberger, D.; Abramovich, H.

2014-03-01

The present manuscript is aimed at describing the PEASSS - PiezoElectric Assisted Smart Satellite Structure project, which was initiated at the beginning of 2013 and financed by the Seventh Framework Program (FP7) of the European Commission. The aims of the project were to develop, manufacture, test and qualify "smart structures" which combine composite panels, piezoelectric materials, and next generation sensors, for autonomously improved pointing accuracy and power generation in space. The smart panels will enable fine angle control, and thermal and vibration compensation, improving all types of future Earth observations, such as environmental and planetary mapping, border and regional imaging. This new technology will help keep Europe on the cutting edge of space research, potentially improving the cost and development time for more accurate future sensor platforms including synthetic aperture optics, moving target detection and identification, and compact radars. The system components include new nano-satellite electronics, a piezo power generation system based on the pyroelectric effect, a piezo actuated smart structure, and a fiber-optic sensor and interrogator system. The present paper will deal only with two of the components, namely the piezo power generation system and the piezo actuated smart structure The designs are going to be prototyped into breadboard models for functional development and testing. Following completion of operational breadboards, components will evolve to flight-test ready hardware and related software, ready to be integrated into a working satellite. Once the nanosattelite is assembled, on ground tests will be performed. Finally, the satellite will be launched and tested in space at the end of 2015.

Smart Metamaterial Based on the Simplex Tensegrity Pattern.

PubMed

Al Sabouni-Zawadzka, Anna; Gilewski, Wojciech

2018-04-26

In the present paper, a novel cellular metamaterial that was based on a tensegrity pattern is presented. The material is constructed from supercells, each of which consists of eight 4-strut simplex modules. The proposed metamaterial exhibits some unusual properties, which are typical for smart structures. It is possible to control its mechanical characteristics by adjusting the level of self-stress or by changing the properties of structural members. A continuum model is used to identify the qualitative properties of the considered metamaterial, and to estimate how the applied self-stress and the characteristics of cables and struts affect the whole structure. The performed analyses proved that the proposed structure can be regarded as a smart metamaterial with orthotropic properties. One of its most important features are unique values of Poisson’s ratio, which can be either positive or negative, depending on the applied control parameters. Moreover, all of the mechanical characteristics of the proposed metamaterial are prone to structural control.

Virtual Parts Engineering Research Center

DTIC Science & Technology

2010-05-20

engineering 10 materials. High strength alloys , composites (polymer composites and metallic composites), and the like cannot merely be replaced by...ceramics, smart materials, shape memory alloys , super plastic materials and nano- structured materials may be more appropriate substitutes in a reverse...molding process using thermosetting Bakelite. For remanufacturing the part in small quantities, machining has been identified as the most economical

Materials science. Materials that couple sensing, actuation, computation, and communication.

PubMed

McEvoy, M A; Correll, N

2015-03-20

Tightly integrating sensing, actuation, and computation into composites could enable a new generation of truly smart material systems that can change their appearance and shape autonomously. Applications for such materials include airfoils that change their aerodynamic profile, vehicles with camouflage abilities, bridges that detect and repair damage, or robotic skins and prosthetics with a realistic sense of touch. Although integrating sensors and actuators into composites is becoming increasingly common, the opportunities afforded by embedded computation have only been marginally explored. Here, the key challenge is the gap between the continuous physics of materials and the discrete mathematics of computation. Bridging this gap requires a fundamental understanding of the constituents of such robotic materials and the distributed algorithms and controls that make these structures smart. Copyright © 2015, American Association for the Advancement of Science.

Smart and hybrid materials: perspectives for their use in textile structures for better health care.

PubMed

Carosio, Stefano; Monero, Alessandra

2004-01-01

High tech materials such as Shape Memory Alloys can be effectively integrated in textiles, thus providing multifunctional garments with potential application to the health care industry or for simply improving the quality of life. The objective of the present paper is to describe the development of a novel hybrid fabric with embedded shape memory (Nitinol) wires, and the related clothing application with the capability of recovering any shape depending upon the environment and becoming superelastic. The use of these smart garments for biomedical applications will be illustrated, thus opening new perspectives for enhanced health care provision.

Design, fabrication and control of origami robots

NASA Astrophysics Data System (ADS)

Rus, Daniela; Tolley, Michael T.

2018-06-01

Origami robots are created using folding processes, which provide a simple approach to fabricating a wide range of robot morphologies. Inspired by biological systems, engineers have started to explore origami folding in combination with smart material actuators to enable intrinsic actuation as a means to decouple design from fabrication complexity. The built-in crease structure of origami bodies has the potential to yield compliance and exhibit many soft body properties. Conventional fabrication of robots is generally a bottom-up assembly process with multiple low-level steps for creating subsystems that include manual operations and often multiple iterations. By contrast, natural systems achieve elegant designs and complex functionalities using top-down parallel transformation approaches such as folding. Folding in nature creates a wide spectrum of complex morpho-functional structures such as proteins and intestines and enables the development of structures such as flowers, leaves and insect wings. Inspired by nature, engineers have started to explore folding powered by embedded smart material actuators to create origami robots. The design and fabrication of origami robots exploits top-down, parallel transformation approaches to achieve elegant designs and complex functionalities. In this Review, we first introduce the concept of origami robotics and then highlight advances in design principles, fabrication methods, actuation, smart materials and control algorithms. Applications of origami robots for a variety of devices are investigated, and future directions of the field are discussed, examining both challenges and opportunities.

Smart fiber-reinforced polymer anchorage system with optical fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Huang, Minghua; Zhou, Zhi; He, Jianping; Chen, Genda; Ou, Jinping

2010-03-01

Civil Engineers have used fiber reinforced polymer (FRP) with high axial strength as an effective and economical alternative to steel in harsh corrosion environments. However, the practical applications of FRP are limited by the tendency of FRP materials to fail suddenly under lateral pressure and surface injury. For example, shear stresses result from the bonding effect between the FRP material and the structure of the anchorage system due to the lower shear strength of FRP. This paper proposes a novel smart FRP anchorage system with embedded optical fiber Bragg grating (FBG) sensors to monitor the axial strain state and accordingly the interfacial shear stress, as well as the interfacial damage characteristics of FRP anchorage. One FBG sensor was embedded in an FRP rod outside the anchorage region to evaluate the properties of the material, and seven FBG sensors were distributed along the rod in the anchor to monitor the axial strain variations and study the interfacial mechanical behaviors of the smart FRP anchorage under a static pulling load. The experimental results agreed well with theoretical predictions. The smart FRP anchorage system with optical FBG sensors proves effective and practical for monitoring the long-term mechanical behavior of FRP anchorage systems.

MEMS- and NEMS-based smart devices and systems

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.

2001-11-01

The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sized now don at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: 1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic an micro molding techniques; 2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; 3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; 4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sensing and control of a variety functions in automobile, aerospace, marine and civil structures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H2-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5-40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended conventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross- linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

Characterization on Smart Optics Using Ellipsometry

NASA Technical Reports Server (NTRS)

Song, Kyo D.

2002-01-01

Recently, NASA Langley Research Center developed a smart active optical concept to filter narrow band pass or to control optical intensity. To characterize developed smart optics materials, we have measured thickness and reflection properties of the materials using a WVASE32 ellipsometry. This project allowed us to: (1) prepare the smart optical materials for measurement of thickness and optical properties at NASA Langley Research Center; (2) measure thickness and optical properties of the smart optical materials; (3) evaluate the measured properties in terms of applications for narrow band-pass filters. The outcomes of this research provide optical properties and physical properties of the smart optics on a selected spectral range. The applications of this development were used for field-controlled spectral smart filters.

Automating the application of smart materials for protein crystallization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khurshid, Sahir; Govada, Lata; EL-Sharif, Hazim F.

2015-03-01

The first semi-liquid, non-protein nucleating agent for automated protein crystallization trials is described. This ‘smart material’ is demonstrated to induce crystal growth and will provide a simple, cost-effective tool for scientists in academia and industry. The fabrication and validation of the first semi-liquid nonprotein nucleating agent to be administered automatically to crystallization trials is reported. This research builds upon prior demonstration of the suitability of molecularly imprinted polymers (MIPs; known as ‘smart materials’) for inducing protein crystal growth. Modified MIPs of altered texture suitable for high-throughput trials are demonstrated to improve crystal quality and to increase the probability of successmore » when screening for suitable crystallization conditions. The application of these materials is simple, time-efficient and will provide a potent tool for structural biologists embarking on crystallization trials.« less

Light-responsive smart surface with controllable wettability and excellent stability.

PubMed

Zhou, Yin-Ning; Li, Jin-Jin; Zhang, Qing; Luo, Zheng-Hong

2014-10-21

Novel fluorinated gradient copolymer was designed for smart surface with light-responsive controllable wettability and excellent stability. The switchable mechanism and physicochemical characteristics of the as-prepared surface decorated by designed polymeric material were investigated by ultraviolet-visible (UV-vis) spectrum, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Thanks to the functional film and surface roughening, etched silicon surface fabricated by copolymer involving spiropyran (Sp) moieties possesses a fairly large variation range of WCA (28.1°) and achieves the transformation between hydrophilicity (95.2° < 109.2°) and hydrophobicity (123.3° > 109.2°) relative to blank sample (109.2°). The synthetic strategy and developed smart surface offer a promising application in coating with controllable wettability, which bridge the gap between chemical structure and material properties.

Advanced Material Strategies for Next-Generation Additive Manufacturing

PubMed Central

Chang, Jinke; He, Jiankang; Zhou, Wenxing; Lei, Qi; Li, Xiao; Li, Dichen

2018-01-01

Additive manufacturing (AM) has drawn tremendous attention in various fields. In recent years, great efforts have been made to develop novel additive manufacturing processes such as micro-/nano-scale 3D printing, bioprinting, and 4D printing for the fabrication of complex 3D structures with high resolution, living components, and multimaterials. The development of advanced functional materials is important for the implementation of these novel additive manufacturing processes. Here, a state-of-the-art review on advanced material strategies for novel additive manufacturing processes is provided, mainly including conductive materials, biomaterials, and smart materials. The advantages, limitations, and future perspectives of these materials for additive manufacturing are discussed. It is believed that the innovations of material strategies in parallel with the evolution of additive manufacturing processes will provide numerous possibilities for the fabrication of complex smart constructs with multiple functions, which will significantly widen the application fields of next-generation additive manufacturing. PMID:29361754

Advanced Material Strategies for Next-Generation Additive Manufacturing.

PubMed

Chang, Jinke; He, Jiankang; Mao, Mao; Zhou, Wenxing; Lei, Qi; Li, Xiao; Li, Dichen; Chua, Chee-Kai; Zhao, Xin

2018-01-22

Additive manufacturing (AM) has drawn tremendous attention in various fields. In recent years, great efforts have been made to develop novel additive manufacturing processes such as micro-/nano-scale 3D printing, bioprinting, and 4D printing for the fabrication of complex 3D structures with high resolution, living components, and multimaterials. The development of advanced functional materials is important for the implementation of these novel additive manufacturing processes. Here, a state-of-the-art review on advanced material strategies for novel additive manufacturing processes is provided, mainly including conductive materials, biomaterials, and smart materials. The advantages, limitations, and future perspectives of these materials for additive manufacturing are discussed. It is believed that the innovations of material strategies in parallel with the evolution of additive manufacturing processes will provide numerous possibilities for the fabrication of complex smart constructs with multiple functions, which will significantly widen the application fields of next-generation additive manufacturing.

Welcome to the 2014 volume of Smart Materials and Structures

NASA Astrophysics Data System (ADS)

Garcia, Ephrahim

2014-01-01

Welcome to Smart Materials and Structures (SMS). Smart materials and structures are comprised of structural matter that responds to a stimulus. These materials can be controlled or have properties that can be altered in a prescribed manner. Smart materials generate non-traditional forms of transduction. We are all familiar with common forms of transduction, electromechanical motors. Lorenz's forces utilize permanent and variable magnets, controlled by current, to generate magnetically generated forces that oppose each other. Utilizing this simple principal we have advanced the industrial revolution of the 19th Century by the creation of the servo-mechanism. Controlled velocity and position generation systems that have automated manufacturing, our machines and the very environs in which we dwell. Smart materials often rely on a variety of new and different methods of transduction. Piezoelectric, magnetostrictive, electrostrictive, and phase-change materials, such as shape memory alloys, are among the most common smart materials. Other approaches such as polymer actuators that rely on complex three-dimensional chemical-based composites are also emerging. The trinity of engineering research is analysis, simulation and experimentation. To perform analyses we must understand the physical phenomena at hand in order to develop a mathematical model for the problem. These models form the basis of simulation and complex computational modeling of a system. It is from these models that we begin to expand our understanding about what is possible, ultimately developing simulation-based tools that verify new designs and insights. Experimentation offers the opportunity to verify our analyses and simulations in addition to providing the 'proof of the pudding' so to speak. But it is our ability to simulate that guides us and our expectations, predicting the behavior of what we may see in the lab or in a prototype. Experimentation ultimately provides the feedback to our modeling efforts. We capture all elements of this trinity in the journal for both smart materials and structures, devices and mechanisms, which are being developed by our community. Innovations often arise as we find new ways to incorporate and control materials. We can utilize these unusual properties to design and fabricate material architectures for transduction unlike anything done in the past. The distributed nature of the material transduction lends itself to new ways of thinking, making the actuators integral to the structure, developing new formulations for controls and changing how we design power electronics for the system. Once again the 2013 volume of SMS surpassed all expectations and grew by 38% while maintaining a high reject rate of almost 60% and high impact factor of 2.024. We are delighted that more and more researchers are choosing SMS to showcase their work. It also means that this year there will be an increased emphasis on selecting only work of the highest interest and quality for publication. A few months ago SMS moved to ScholarOne, our new state-of-the-art editorial management system, in order to help us to cope with our ever-increasing copy flow and enable us to continue providing our authors and referees with a modern, fast and efficient process. From now on all manuscripts should be submitted to us at http://mc04.manuscriptcentral.com/sms-iop. Thanks to the new system, we are now able to run every submission through our plagiarism software, Crosscheck. Last year, SMS published two exciting focus issues called 'Bioinspired smart materials and systems' and 'Auxetics in smart systems and structures'. Focus issues in SMS are designed to provide a timely snap shot of a particular topic and are popular with both our readers and contributing authors. In 2013, SMS also published two special issues. (1) The annual SMASIS 2013 special issue covering the multifunctional materials, active materials, and bioinspired materials symposia and including, for the first time, the energy harvesting symposium. (2) A special issue called 'Electromechanically active polymer (EAP) transducers: research in Europe', a collection of articles from the European Scientific Network for Artificial Muscles—ESNAM group. This year, look out for focus issues put together by the editorial board on 'fluidic artificial muscles' and 'active materials and structures for origami engineering'. We will also continue to run a busy program of Topical Reviews, which are often among the most cited and most downloaded articles in the journal. Congratulations to Ganesh Raghunath and his team (University of Maryland) who won the Smart Materials and Structures prize for the best paper at SMASIS 2013, and to Kyle Mulligan and his team (University of Sherbrooke) who won our best student paper prize at Cansmart 2013. We were delighted with the news last year that ASME awarded two of its prestigious annual best paper awards to articles published in SMS: the 2013 ASME 'Adaptive Structures and Material Systems Best Paper Award in Adaptive Materials and Material Systems' went to Donghyeon Ryu and Kenneth J Loh for their article 'Strain sensing using photocurrent generated by photoactive P3HT-based nanocomposites'. The 2013 ASME 'Adaptive Structures and Material Systems Best Paper Award in Structural Dynamics and Control' went to Julianna Abel, Jonathan Luntz and Diann Brei for their article 'A two-dimensional analytical model and experimental validation of garter stitch knitted shape memory alloy actuator architecture'. Finally, may I take this opportunity to thank our fantastic Editorial board of Associate Editors who tirelessly oversee the review of each submitted article and give their invaluable advice, helping to develop and shape the journal. Welcome to Professor Alper Erturk who has recently joined us. We also acknowledge and thank Professor Andrea Del Grosso, Professor Sami Masri, Professor Seung Jo Kim and Professor Christian Boller who retired from the Board last year after many years in service as Associate Editors. Associate Editors in 2013: Professor G Akhras, Royal Military College of Canada, Ontario, Canada Professor C Boller, University of Saarland, Saarbrücken, Germany Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren, Dresden, Germany Professor J Cagnol, École Centrale Paris, France Professor G Carman, University of California-Los Angeles, USA Professor S-B Choi, Inha University, Incheon, Korea Professor S H Choi, NASA Langley Research Center, Hampton, VA, USA Professor A Del Grosso, Università degli Studi di Genova, Italy Professor A Erturk, Georgia Institute of Technology, GA, USA Professor U Gabbert, Universität Magdeburg, Germany Professor A Güemes, Universidad Politecnica de Madrid, Spain Professor S Gopalakrishnan, Indian Institute of Science, Bangalore, India Professor J Kim, Inha University, Incheon, Korea Professor K J Kim, University of Nevada, Reno, USA Professor S J Kim, Seoul National University, Korea Professor D Lagoudas, Texas A&M University, College Station, USA Professor R Lammering, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg, Hamburg, Germany Professor C K Lee, National Taiwan University, Taiwan Professor W Li, University of Wollongong, Australia Professor W H Liao, Chinese University of Hong Kong, China Professor Y Liu, Harbin Institute of Technology, China Professor C S Lynch, University of California-Los Angeles, USA Professor S Masri, University of Southern California, Los Angeles, USA Professor W M Ostachowicz, Polish Academy of Sciences, Gdansk, Poland Professor K Peters, North Carolina State University, Raleigh, USA Professor M Shahinpoor, University of Maine, Orono, USA Professor H Sodano, University of Florida, Gainsville, USA Professor G Song, University of Houston, TX, USA Professor W J Staszewski, AGH University of Science and Technology, Kraków, Poland Professor N Takeda, University of Tokyo, Japan Professor D-H Wang, Chongqing University, China Professor Q Wang, University of Manitoba, Canada Professor N M Wereley, University of Maryland, College Park, USA Professor W J Wu, National Taiwan University, Taiwan.

On location of piezoelectric element in a smart-structure: numerical investigation and experiment

NASA Astrophysics Data System (ADS)

Oshmarin, D.; Iurlov, M.

2017-06-01

In this paper, based on some example problems it was demonstrated that in examining the possibilities of smart structure applications, the matter of considerable researchers’ concern is the problem of location of piezoelectric elements in the structure to allow effective realization of its smart functions in the framework of the specified strategy of structure control and target purposes (vibration damping, defectoscopy, etc.) The numerical and experimental investigations have shown that for structures with the elements made of piezoelectric materials, it is more convenient to use as a parameter, specifying the best location of the piezoelectric element for damping the vibrations at the prescribed frequency, the coefficient of electromechanical coupling, which is evaluated by the values of eigenfrequencies of the structure in the short-circuit and open-circuit regimes. The values of eigenfrequencies of vibrations are evaluated by solving the problem of natural vibrations of electromechanical systems by the finite element method using the applied ANSYS package. The investigation were conducted for a thin-walled aluminum shell in the form of half-cylinder.

Beads-on-String Structured Nanofibers for Smart and Reversible Oil/Water Separation with Outstanding Antifouling Property.

PubMed

Wang, Yuanfeng; Lai, Chuilin; Wang, Xiaowen; Liu, Yang; Hu, Huawen; Guo, Yujuan; Ma, Kaikai; Fei, Bin; Xin, John H

2016-09-28

It is challenging to explore a unified solution for the treatment of oily wastewater from complex sources. Thus, membrane materials with flexible separation schemes are highly desired. Herein, we fabricated a smart membrane by electrospinning TiO2 doped polyvinylidene fluoride (PVDF) nanofibers. The as-formed beads-on-string structure and hierarchical roughness of the nanofibers contribute to its superwetting/resisting property to liquids, which is desirable in oil/water separation. Switched simply by UV (or sunlight) irradiation and heating treatment, the smart membrane can realize reversible separation of oil/water mixtures by selectively allowing water or oil to pass through alone. Most importantly, the as-prepared nanofiber membrane possesses outstanding antifouling and self-cleaning performance resulting from the photocatalytic property of TiO2, which has practical significance in saving solvents and recycling materials. This work provides a route for fabricating cost-effective, easily scaled up, and recyclable membranes for on-demand oil/water separation in versatile situations, which can be of great usage in the new green separation technology.

Electrochemically Smart Bimetallic Materials Featuring Group 11 Metals: In-situ Conductive Network Generation and Its Impact on Cell Capacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeuchi, Esther

2016-11-30

Our results for this program “Electrochemically smart bimetallic materials featuring Group 11 metals: in-situ conductive matrix generation and its impact on battery capacity, power and reversibility” have been highly successful: 1) we demonstrated material structures which generated in-situ conductive networks through electrochemical activation with increases in conductivity up to 10,000 fold, 2) we pioneered in situ analytical methodology to map the cathodes at several stages of discharge through the use of Energy Dispersive X-ray Diffraction (EDXRD) to elucidate the kinetic dependence of the conductive network formation, and 3) we successfully designed synthetic methodology for direct control of material properties includingmore » crystallite size and surface area which showed significant impact on electrochemical behavior.« less

Smart Materials and Structures-Smart Wing. Volumes 1, 2, 3 and 4

DTIC Science & Technology

1998-12-01

repeatable fashion when heat is applied. Therefore, once the pre-twist is successfully applied and the tube is installed in the model, heating the...modules were operated and calibrated online by the PSI 8400 Control System. Because the transducer modules are extremely sensitive to temperature, a...again substantiates that adaptive features tend to support each other, though not necessarily in a completely linear fashion , and essentially provide a

Smart-actuated continuous moldline technology (CMT) mini wind tunnel test

NASA Astrophysics Data System (ADS)

Pitt, Dale M.; Dunne, James P.; Kilian, Kevin J.

1999-07-01

The Smart Aircraft and Marine Propulsion System Demonstration (SAMPSON) Program will culminate in two separate demonstrations of the application of Smart Materials and Structures technology. One demonstration will be for an aircraft application and the other for marine vehicles. The aircraft portion of the program will examine the application of smart materials to aircraft engine inlets which will deform the inlet in-flight in order to regulate the airflow rate into the engine. Continuous Moldline Technology (CMT), a load-bearing reinforced elastomer, will enable the use of smart materials in this application. The capabilities of CMT to withstand high-pressure subsonic and supersonic flows were tested in a sub-scale mini wind- tunnel. The fixture, used as the wind-tunnel test section, was designed to withstand pressure up to 100 psi. The top and bottom walls were 1-inch thick aluminum and the side walls were 1-inch thick LEXAN. High-pressure flow was introduced from the Boeing St. Louis poly-sonic wind tunnel supply line. CMT walls, mounted conformal to the upper and lower surfaces, were deflected inward to obtain a converging-diverging nozzle. The CMT walls were instrumented for vibration and deflection response. Schlieren photography was used to establish shock wave motion. Static pressure taps, embedded within one of the LEXAN walls, monitored pressure variation in the mini-wind tunnel. High mass flow in the exit region. This test documented the response of CMT technology in the presence of high subsonic flow and provided data to be used in the design of the SAMPSON Smart Inlet.

Natural frequency identification of smart washer by using adaptive observer

NASA Astrophysics Data System (ADS)

Ito, Hitoshi; Okugawa, Masayuki

2014-04-01

Bolted joints are used in many machines/structures and some of them have been loosened during long time use, and unluckily these bolt loosening may cause a great accident of machines/structures system. These bolted joint, especially in important places, are main object of maintenance inspection. Maintenance inspection with human- involvement is desired to be improved owing to time-consuming, labor-intensive and high-cost. By remote and full automation monitoring of the bolt loosening, constantly monitoring of bolted joint is achieved. In order to detect loosening of bolted joints without human-involvement, applying a structural health monitoring technique and smart structures/materials concept is the key objective. In this study, a new method of bolt loosening detection by adopting a smart washer has been proposed, and the basic detection principle was discussed with numerical analysis about frequency equation of the system, was confirmed experimentally. The smart washer used in this study is in cantilever type with piezoelectric material, which adds the washer the self-sensing and actuation function. The principle used to detect the loosening of the bolts is a method of a bolt loosening detection noted that the natural frequency of a smart washer system is decreasing by the change of the bolt tightening axial tension. The feature of this proposed method is achieving to identify the natural frequency at current condition on demand by adopting the self-sensing and actuation function and system identification algorithm for varying the natural frequency depending the bolt tightening axial tension. A novel bolt loosening detection method by adopting adaptive observer is proposed in this paper. The numerical simulations are performed to verify the possibility of the adaptive observer-based loosening detection. Improvement of the detection accuracy for a bolt loosening is confirmed by adopting initial parameter and variable adaptive gain by numerical simulation.

Nanotechnology: MEMS and NEMS and their applications to smart systems and devices

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.

2003-10-01

The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with features sizes now down at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: (1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic and micro molding techniques; (2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; (3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; (4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems. The integration of NEMS (NanoElectroMechanical Systems), MEMS, IDTs (Interdigital Transducers) and required microelectronics and conformal antenna in the multifunctional smart materials and composites results in a smart system suitable for sending and control of a variety functions in automobile, aerospace, marine and civil strutures and food and medical industries. This unique combination of technologies also results in novel conformal sensors that can be remotely sensed by an antenna system with the advantage of no power requirements at the sensor site. This paper provides a brief review of MEMS and NEMS based smart systems for various applications mentioned above. Carbon Nano Tubes (CNT) with their unique structure, have already proven to be valuable in their application as tips for scanning probe microscopy, field emission devices, nanoelectronics, H2-storage, electromagnetic absorbers, ESD, EMI films and coatings and structural composites. For many of these applications, highly purified and functionalized CNT which are compatible with many host polymers are needed. A novel microwave CVD processing technique to meet these requirements has been developed at Penn State Center for the Engineering of Electronic and Acoustic Materials and Devices (CEEAMD). This method enables the production of highly purified carbon nano tubes with variable size (from 5 - 40 nm) at low cost (per gram) and high yield. Whereas, carbon nano tubes synthesized using the laser ablation or arc discharge evaporation method always include impurity due to catalyst or catalyst support. The Penn State research is based on the use of zeolites over other metal/metal oxides in the microwave field for a high production and uniformity of the product. An extended coventional purification method has been employed to purify our products in order to remove left over impurity. A novel composite structure can be tailored by functionalizing carbon nano tubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and Mechanical-MEMS devices derived from this hybrid composites will be presented.

The Aircraft Morphing Program

NASA Technical Reports Server (NTRS)

Wlezien, R. W.; Horner, G. C.; McGowan, A. R.; Padula, S. L.; Scott, M. A.; Silcox, R. J.; Simpson, J. O.

1998-01-01

In the last decade smart technologies have become enablers that cut across traditional boundaries in materials science and engineering. Here we define smart to mean embedded actuation, sensing, and control logic in a tightly coupled feedback loop. While multiple successes have been achieved in the laboratory, we have yet to see the general applicability of smart devices to real aircraft systems. The NASA Aircraft Morphing program is an attempt to couple research across a wide range of disciplines to integrate smart technologies into high payoff aircraft applications. The program bridges research in seven individual disciplines and combines the effort into activities in three primary program thrusts. System studies are used to assess the highest- payoff program objectives, and specific research activities are defined to address the technologies required for development of smart aircraft systems. In this paper we address the overall program goals and programmatic structure, and discuss the challenges associated with bringing the technologies to fruition.

Assuring Life in Composite Systems

NASA Technical Reports Server (NTRS)

Chamis, Christos c.

2008-01-01

A computational simulation method is presented to assure life in composite systems by using dynamic buckling of smart composite shells as an example. The combined use of composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right below the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 9% at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load. The uncertainties in the electric field strength and smart material volume fraction have moderate effects and thereby in the assured life of the shell.

Ultra-Low-Power Smart Electronic Nose System Based on Three-Dimensional Tin Oxide Nanotube Arrays.

PubMed

Chen, Jiaqi; Chen, Zhuo; Boussaid, Farid; Zhang, Daquan; Pan, Xiaofang; Zhao, Huijuan; Bermak, Amine; Tsui, Chi-Ying; Wang, Xinran; Fan, Zhiyong

2018-06-04

In this work, we present a high-performance smart electronic nose (E-nose) system consisting of a multiplexed tin oxide (SnO 2 ) nanotube sensor array, read-out circuit, wireless data transmission unit, mobile phone receiver, and data processing application (App). Using the designed nanotube sensor device structure in conjunction with multiple electrode materials, high-sensitivity gas detection and discrimination have been achieved at room temperature, enabling a 1000 times reduction of the sensor's power consumption as compared to a conventional device using thin film SnO 2 . The experimental results demonstrate that the developed E-nose can identify indoor target gases using a simple vector-matching gas recognition algorithm. In addition, the fabricated E-nose has achieved state-of-the-art sensitivity for H 2 and benzene detection at room temperature with metal oxide sensors. Such a smart E-nose system can address the imperative needs for distributed environmental monitoring in smart homes, smart buildings, and smart cities.

NASA Langley Research Center's Contributions to International Active Buffeting Alleviation Programs

NASA Technical Reports Server (NTRS)

Moses, Robert W.

2000-01-01

Buffeting is an aeroelastic phenomenon which plagues high performance aircraft, especially those with twin vertical tails like the F/A-18, at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. By means of wind-tunnel and flight tests, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can be increased by structural enhancements to the airframe. In more recent years, buffeting alleviation through active control of smart materials has been highly researched in wind-tunnel proof-of-concept demonstrations and full-scale ground tests using the F/A-18 as a test bed. Because the F/A-18 resides in fleets outside as well as inside the United States, these tests have evolved into international collaborative research activities with Australia and Canada, coordinated by the Air Force Research Laboratory (AFRL) and conducted under the auspices of The Technical Cooperation Program (TTCP). With the recent successes and advances in smart materials, the main focus of these buffeting alleviation tests has also evolved to a new level: utilize the F/A-18 as a prototype to mature smart materials for suppressing vibrations of aerospace structures. The role of the NASA Langley Research Center (LaRC) in these programs is presented.

Contributions to Active Buffeting Alleviation Programs by the NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Moses, Robert W.

1999-01-01

Buffeting is an aeroelastic phenomenon which plagues high performance aircraft, especially those with twin vertical tails like the F/A-18, at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. By means of wind-tunnel and flight tests, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can be increased by structural enhancements to the airframe. In more recent years, buffeting alleviation through active control of smart materials has been highly researched in wind-tunnel proof-of-concept demonstrations and full-scale ground tests using the F/A-18 as a test bed. Because the F/A-18 resides in fleets outside as well as inside the United States, these tests have evolved into international collaborative research activities with Australia and Canada, coordinated by the Air Force Research Laboratory (AFRL) and conducted under the auspices of The Technical Cooperation Program (TTCP). With the recent successes and advances in smart materials, the main focus of these buffeting alleviation tests has also evolved to a new level: utilize the F/A-18 as a prototype to mature smart materials for suppressing vibrations of aerospace structures. The role of the NASA Langley Research Center (LaRC) in these programs is presented.

Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 4 - Tribological materials and NDE

NASA Technical Reports Server (NTRS)

Fusaro, Robert L. (Editor); Achenbach, J. D. (Editor)

1993-01-01

The present volume on tribological materials and NDE discusses liquid lubricants for advanced aircraft engines, a liquid lubricant for space applications, solid lubricants for aeronautics, and thin solid-lubricant films in space. Attention is given to the science and technology of NDE, tools for an NDE engineering base, experimental techniques in ultrasonics for NDE and material characterization, and laser ultrasonics. Topics addressed include thermal methods of NDE and quality control, digital radiography in the aerospace industry, materials characterization by ultrasonic methods, and NDE of ceramics and ceramic composites. Also discussed are smart materials and structures, intelligent processing of materials, implementation of NDE technology on flight structures, and solid-state weld evaluation.

Three-Axis Distributed Fiber Optic Strain Measurement in 3D Woven Composite Structures

NASA Technical Reports Server (NTRS)

Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

2013-01-01

Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading. Keywords: fiber optic, distributed strain sensing, Rayleigh scatter, optical frequency domain reflectometry

Smart materials systems through mesoscale patterning

NASA Astrophysics Data System (ADS)

Aksay, Ilhan A.; Groves, John T.; Gruner, Sol M.; Lee, P. C. Y.; Prud'homme, Robert K.; Shih, Wei-Heng; Torquato, Salvatore; Whitesides, George M.

1996-02-01

We report work on the fabrication of smart materials with two unique strategies: (1) self- assembly and (2) laser stereolithography. Both methods are akin to the processes used by biological systems. The first one is ideal for pattern development and the fabrication of miniaturized units in the submicron range and the second one in the 10 micrometer to 1 mm size range. By using these miniaturized units as building blocks, one can also produce smart material systems that can be used at larger length scales such as smart structural components. We have chosen to focus on two novel piezoceramic systems: (1) high-displacement piezoelectric actuators, and (2) piezoceramic hydrophone composites possessing negative Poisson ratio matrices. High-displacement actuators are essential in such applications as linear motors, pumps, switches, loud speakers, variable-focus mirrors, and laser deflectors. Arrays of such units can potentially be used for active vibration control of helicopter rotors as well as the fabrication of adaptive rotors. In the case of piezoceramic hydrophone composites, we utilize matrices having a negative Poisson's ratio in order to produce highly sensitive, miniaturized sensors. We envision such devices having promising new application areas such as the implantation of hydrophones in small blood vessels to monitor blood pressure. Negative Poisson ratio materials have promise as robust shock absorbers, air filters, and fasteners, and hence, can be used in aircraft and land vehicles.

Smart Screening System (S3) In Taconite Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daryoush Allaei; Angus Morison; David Tarnowski

2005-09-01

The conventional screening machines used in processing plants have had undesirable high noise and vibration levels. They also have had unsatisfactorily low screening efficiency, high energy consumption, high maintenance cost, low productivity, and poor worker safety. These conventional vibrating machines have been used in almost every processing plant. Most of the current material separation technology uses heavy and inefficient electric motors with an unbalanced rotating mass to generate the shaking. In addition to being excessively noisy, inefficient, and high-maintenance, these vibrating machines are often the bottleneck in the entire process. Furthermore, these motors, along with the vibrating machines and supportingmore » structure, shake other machines and structures in the vicinity. The latter increases maintenance costs while reducing worker health and safety. The conventional vibrating fine screens at taconite processing plants have had the same problems as those listed above. This has resulted in lower screening efficiency, higher energy and maintenance cost, and lower productivity and workers safety concerns. The focus of this work is on the design of a high performance screening machine suitable for taconite processing plants. SmartScreens{trademark} technology uses miniaturized motors, based on smart materials, to generate the shaking. The underlying technologies are Energy Flow Control{trademark} and Vibration Control by Confinement{trademark}. These concepts are used to direct energy flow and confine energy efficiently and effectively to the screen function. The SmartScreens{trademark} technology addresses problems related to noise and vibration, screening efficiency, productivity, and maintenance cost and worker safety. Successful development of SmartScreens{trademark} technology will bring drastic changes to the screening and physical separation industry. The final designs for key components of the SmartScreens{trademark} have been developed. The key components include smart motor and associated electronics, resonators, and supporting structural elements. It is shown that the smart motors have an acceptable life and performance. Resonator (or motion amplifier) designs are selected based on the final system requirement and vibration characteristics. All the components for a fully functional prototype are fabricated. The development program is on schedule. The last semi-annual report described the process of FE model validation and correlation with experimental data in terms of dynamic performance and predicted stresses. It also detailed efforts into making the supporting structure less important to system performance. Finally, an introduction into the dry application concept was presented. Since then, the design refinement phase was completed. This has resulted in a Smart Screen design that meets performance targets both in the dry condition and with taconite slurry flow using PZT motors. Furthermore, this system was successfully demonstrated for the DOE and partner companies at the Coleraine Mineral Research Laboratory in Coleraine, Minnesota.« less

Smart wing wind tunnel test results

NASA Astrophysics Data System (ADS)

Scherer, Lewis B.; Martin, Christopher A.; Appa, Kari; Kudva, Jayanth N.; West, Mark N.

1997-05-01

The use of smart materials technologies can provide unique capabilities in improving aircraft aerodynamic performance. Northrop Grumman built and tested a 16% scale semi-span wind tunnel model of the F/A-18 E/F for the on-going DARPA/WL Smart Materials and Structures-Smart Wing Program. Aerodynamic performance gains to be validated included increase in the lift to drag ratio, increased pitching moment (Cm), increased rolling moment (Cl) and improved pressure distribution. These performance gains were obtained using hingeless, contoured trailing edge control surfaces with embedded shape memory alloy (SMA) wires and spanwise wing twist via a SMA torque tube and are compared to a conventional wind tunnel model with hinged control surfaces. This paper presents an overview of the results from the first wind tunnel test performed at the NASA Langley's 16 ft Transonic Dynamic Tunnel. Among the benefits demonstrated are 8 - 12% increase in rolling moment due to wing twist, a 10 - 15% increase in rolling moment due to contoured aileron, and approximately 8% increase in lift due to contoured flap, and improved pressure distribution due to trailing edge control surface contouring.

The role of local interaction mechanics in fiber optic smart structures

NASA Astrophysics Data System (ADS)

Sirkis, J. S.; Dasgupta, A.

1993-04-01

The concept of using 'smart' composite materials/structures with built-in self-diagnostic capabilities for health monitoring involves embedding discrete and/or distributed sensory networks in the host composite material, along with a central and/or distributed artificial intelligence capability for signal processing, data collection, interpretation and diagnostic evaluations. This article concentrates on the sensory functions in 'smart' structure applications and concentrates in particular on optical fiber sensors. Specifically, we present an overview of recent research dealing with the basic mechanics of local interactions between the embedded optical fiber sensors and the surrounding host composite. The term 'local' is defined by length scales on the order of several optical fiber diameters. We examine some generic issues, such as the 'calibration' and 'obtrusivity' of the sensor, and the inherent damage caused by the sensor inclusions to the surrounding host and vice-versa under internal and/or external applied loads. Analytical, numerical and experimental results are presented regarding the influence of local strain concentrations caused by the sensory inclusions on sensor and host performance. The important issues examined are the local mechanistic effects of optical fiber coatings on the behavior of the sensor and the host, and mechanical survivability of optical fibers experiencing quasi-static and time-varying thermomechanical loading.

Smart Screening System (S3) In Taconite Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daryoush Allaei; Ryan Wartman; David Tarnowski

2006-03-01

The conventional screening machines used in processing plants have had undesirable high noise and vibration levels. They also have had unsatisfactorily low screening efficiency, high energy consumption, high maintenance cost, low productivity, and poor worker safety. These conventional vibrating machines have been used in almost every processing plant. Most of the current material separation technology uses heavy and inefficient electric motors with an unbalanced rotating mass to generate the shaking. In addition to being excessively noisy, inefficient, and high-maintenance, these vibrating machines are often the bottleneck in the entire process. Furthermore, these motors, along with the vibrating machines and supportingmore » structure, shake other machines and structures in the vicinity. The latter increases maintenance costs while reducing worker health and safety. The conventional vibrating fine screens at taconite processing plants have had the same problems as those listed above. This has resulted in lower screening efficiency, higher energy and maintenance cost, and lower productivity and workers safety concerns. The focus of this work is on the design of a high performance screening machine suitable for taconite processing plants. SmartScreens{trademark} technology uses miniaturized motors, based on smart materials, to generate the shaking. The underlying technologies are Energy Flow Control{trademark} and Vibration Control by Confinement{trademark}. These concepts are used to direct energy flow and confine energy efficiently and effectively to the screen function. The SmartScreens{trademark} technology addresses problems related to noise and vibration, screening efficiency, productivity, and maintenance cost and worker safety. Successful development of SmartScreens{trademark} technology will bring drastic changes to the screening and physical separation industry. The final designs for key components of the SmartScreens{trademark} have been developed. The key components include smart motor and associated electronics, resonators, and supporting structural elements. It is shown that the smart motors have an acceptable life and performance. Resonator (or motion amplifier) designs are selected based on the final system requirement and vibration characteristics. All the components for a fully functional prototype are fabricated. The development program is on schedule. The last semi-annual report described the completion of the design refinement phase. This phase resulted in a Smart Screen design that meets performance targets both in the dry condition and with taconite slurry flow using PZT motors. This system was successfully demonstrated for the DOE and partner companies at the Coleraine Mineral Research Laboratory in Coleraine, Minnesota. Since then, the fabrication of the dry application prototype (incorporating an electromagnetic drive mechanism and a new deblinding concept) has been completed and successfully tested at QRDC's lab.« less

MAC/GMC Code Enhanced for Coupled Electromagnetothermoelastic Analysis of Smart Composites

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Arnold, Steven M.; Aboudi, Jacob

2002-01-01

Intelligent materials are those that exhibit coupling between their electromagnetic response and their thermomechanical response. This coupling allows smart materials to react mechanically (e.g., an induced displacement) to applied electrical or magnetic fields (for instance). These materials find many important applications in sensors, actuators, and transducers. Recently interest has arisen in the development of smart composites that are formed via the combination of two or more phases, one or more of which is a smart material. To design with and utilize smart composites, designers need theories that predict the coupled smart behavior of these materials from the electromagnetothermoelastic properties of the individual phases. The micromechanics model known as the generalized method of cells (GMC) has recently been extended to provide this important capability. This coupled electromagnetothermoelastic theory has recently been incorporated within NASA Glenn Research Center's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC). This software package is user friendly and has many additional features that render it useful as a design and analysis tool for composite materials in general, and with its new capabilities, for smart composites as well.

Updates on smart polymeric carrier systems for protein delivery.

PubMed

El-Sherbiny, Ibrahim; Khalil, Islam; Ali, Isra; Yacoub, Magdi

2017-10-01

Smart materials are those materials that are responsive to chemical (organic molecules, chemical agents or specific agents), biochemical (protein, enzymes, growth factors, substrates or ligands), physical (electric field, magnetic field, temperature, pH, ionic strength or radiation) or mechanical (pressure or mechanical stress) signals. These responsive materials interact with the stimuli by changing their properties or conformational structures in a predictable manner. Recently, smart polymers have been utilized in various biomedical applications. Particularly, they have been used as a platform to synthesize stimuli-responsive systems that could deliver therapeutics to a specific site for a specific period with minimal adverse effects. For instance, stimuli-responsive polymers-based systems have been recently reported to deliver different bioactive molecules such as carbohydrates (heparin), chemotherapeutic agents (doxorubicin), small organic molecules (anti-coagulants), nucleic acids (siRNA), and proteins (growth factors and hormones). Protein therapeutics played a fundamental role in treatment of various chronic and some autoimmune diseases. For instance insulin has been used in treatment of diabetes. However, being a protein in nature, insulin delivery is limited by its instability, short half-life, and easy denaturation when administered orally. To overcome these challenges, and as highlighted in this review article, much research efforts have been recently devoted to design and develop convenient smart controlled nanosystems for protein therapeutics delivery.

Graphene-based smart materials

NASA Astrophysics Data System (ADS)

Yu, Xiaowen; Cheng, Huhu; Zhang, Miao; Zhao, Yang; Qu, Liangti; Shi, Gaoquan

2017-09-01

The high specific surface area and the excellent mechanical, electrical, optical and thermal properties of graphene make it an attractive component for high-performance stimuli-responsive or 'smart' materials. Complementary to these inherent properties, functionalization or hybridization can substantially improve the performance of these materials. Typical graphene-based smart materials include mechanically exfoliated perfect graphene, chemical vapour deposited high-quality graphene, chemically modified graphene (for example, graphene oxide and reduced graphene oxide) and their macroscopic assemblies or composites. These materials are sensitive to a range of stimuli, including gas molecules or biomolecules, pH value, mechanical strain, electrical field, and thermal or optical excitation. In this Review, we outline different graphene-based smart materials and their potential applications in actuators, chemical or strain sensors, self-healing materials, photothermal therapy and controlled drug delivery. We also introduce the working mechanisms of graphene-based smart materials and discuss the challenges facing the realization of their practical applications.

Applications of polymeric smart materials to environmental problems.

PubMed Central

Gray, H N; Bergbreiter, D E

1997-01-01

New methods for the reduction and remediation of hazardous wastes like carcinogenic organic solvents, toxic materials, and nuclear contamination are vital to environmental health. Procedures for effective waste reduction, detection, and removal are important components of any such methods. Toward this end, polymeric smart materials are finding useful applications. Polymer-bound smart catalysts are useful in waste minimization, catalyst recovery, and catalyst reuse. Polymeric smart coatings have been developed that are capable of both detecting and removing hazardous nuclear contaminants. Such applications of smart materials involving catalysis chemistry, sensor chemistry, and chemistry relevant to decontamination methodology are especially applicable to environmental problems. PMID:9114277

Electrical/Mechanical Monitoring of Shape Memory Alloy Reinforcing Fibers Obtained by Pullout Tests in SMA/Cement Composite Materials.

PubMed

Kim, Eui-Hyun; Lee, Hyunbae; Kim, Jae-Hwan; Bae, Seung-Muk; Hwang, Heesu; Yang, Heesun; Choi, Eunsoo; Hwang, Jin-Ha

2018-02-22

Self-healing is an essential property of smart concrete structures. In contrast to other structural metals, shape memory alloys (SMAs) offer two unique effects: shape memory effects, and superelastic effects. Composites composed of SMA wires and conventional cements can overcome the mechanical weaknesses associated with tensile fractures in conventional concretes. Under specialized environments, the material interface between the cementitious component and the SMA materials plays an important role in achieving the enhanced mechanical performance and robustness of the SMA/cement interface. This material interface is traditionally evaluated in terms of mechanical aspects, i.e., strain-stress characteristics. However, the current work attempts to simultaneously characterize the mechanical load-displacement relationships synchronized with impedance spectroscopy as a function of displacement. Frequency-dependent impedance spectroscopy is tested as an in situ monitoring tool for structural variations in smart composites composed of non-conducting cementitious materials and conducting metals. The artificial geometry change in the SMA wires is associated with an improved anchoring action that is compatible with the smallest variation in resistance compared with prismatic SMA wires embedded into a cement matrix. The significant increase in resistance is interpreted to be associated with the slip of the SMA fibers following the elastic deformation and the debonding of the SMA fiber/matrix.

Modal Frequency Detection in Composite Beams Using Fiber Optic Sensors

DTIC Science & Technology

1997-04-18

Structures 4, 270-280 (1995). [35] Chen-Jung Li and Ray Asok , "Neural Network Representation of Fatigue Damage Dynamics," Smart Materials and Structures 3...37] Roland Ray Kilcher, "Modal Analysis and Impact Damage Assessment of Composite Laminates: an Experimental Study," M.S. thesis, University of

Wafer-Level Vacuum Packaging of Smart Sensors.

PubMed

Hilton, Allan; Temple, Dorota S

2016-10-31

The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors-"low cost" for ubiquitous presence, and "smart" for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

Responsive hydrogels--structurally and dimensionally optimized smart frameworks for applications in catalysis, micro-system technology and material science.

PubMed

Döring, Artjom; Birnbaum, Wolfgang; Kuckling, Dirk

2013-09-07

Although the technological and scientific importance of functional polymers has been well established over the last few decades, the most recent focus that has attracted much attention has been on stimuli-responsive polymers. This group of materials is of particular interest due to its ability to respond to internal and/or external chemico-physical stimuli, which is often manifested as large macroscopic responses. Aside from scientific challenges of designing stimuli-responsive polymers, the main technological interest lies in their numerous applications ranging from catalysis through microsystem technology and chemomechanical actuators to sensors that have been extensively explored. Since the phase transition phenomenon of hydrogels is theoretically well understood advanced materials based on the predictions can be prepared. Since the volume phase transition of hydrogels is a diffusion-limited process the size of the synthesized hydrogels is an important factor. Consistent downscaling of the gel size will result in fast smart gels with sufficient response times. In order to apply smart gels in microsystems and sensors, new preparation techniques for hydrogels have to be developed. For the up-coming nanotechnology, nano-sized gels as actuating materials would be of great interest.

Smart material platforms for miniaturized devices: implications in disease models and diagnostics.

PubMed

Verma, Ritika; Adhikary, Rishi Rajat; Banerjee, Rinti

2016-05-24

Smart materials are responsive to multiple stimuli like light, temperature, pH and redox reactions with specific changes in state. Various functionalities in miniaturised devices can be achieved through the application of "smart materials" that respond to changes in their surroundings. The change in state of the materials in the presence of a stimulus may be used for on demand alteration of flow patterns in devices, acting as microvalves, as scaffolds for cellular aggregation or as modalities for signal amplification. In this review, we discuss the concepts of smart trigger responsive materials and their applications in miniaturized devices both for organ-on-a-chip disease models and for point-of-care diagnostics. The emphasis is on leveraging the smartness of these materials for example, to allow on demand sample actuation, ion dependent spheroid models for cancer or light dependent contractility of muscle films for organ-on-a-chip applications. The review throws light on the current status, scope for technological enhancements, challenges for translation and future prospects of increased incorporation of smart materials as integral parts of miniaturized devices.

Smart skin spiral antenna with chiral absorber

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.; Varadan, Vasundara V.

1995-05-01

Recently there has been considerable interest toward designing 'smart skins' for aircraft. The smart skin is a composite layer which may contain conformal radars, conformal microstrip antennas or spiral antennas for electromagnetic applications. These embedded antennas will give rise to very low radar cross section (RCS) or can be completely 'hidden' to tracking radar. In addition, they can be used to detect, monitor or even jam other unwanted electromagnetic field signatures. This paper is designed to address some technical advances made to reduce the size of spiral antennas using tunable dielectric materials and chiral absorbers. The purpose is to design, develop and fabricate a thin, wideband, conformal spiral antenna architecture that is structurally integrable and which uses advanced Penn State dielectric and absorber materials to achieve wideband ground planes, and together with low RCS. Traditional practice has been to design radome and antenna as separate entities and then resolve any interface problems during an integration phase. A structurally integrable conformal antenna, however, demands that the functional components be highly integrated both conceptually and in practice. Our concept is to use the lower skin of the radome as a substrate on which the radiator can be made using standard photolithography, thick film or LTCC techniques.

The Exploration Atmospheres Working Group's Report on Space Radiation Shielding Materials

NASA Technical Reports Server (NTRS)

Barghouty, A. F.; Thibeault, S. A.

2006-01-01

This part of Exploration Atmospheres Working Group analyses focuses on the potential use of nonmetallic composites as the interior walls and structural elements exposed to the atmosphere of the spacecraft or habitat. The primary drive to consider nonmetallic, polymer-based composites as an alternative to aluminum structure is due to their superior radiation shielding properties. But as is shown in this analysis, these composites can also be made to combine superior mechanical properties with superior shielding properties. In addition, these composites can be made safe; i.e., with regard to flammability and toxicity, as well as "smart"; i.e., embedded with sensors for the continuous monitoring of material health and conditions. The analysis main conclusions are that (1) smart polymer-based composites are an enabling technology for safe and reliable exploration missions, and (2) an adaptive, synergetic systems approach is required to meet the missions requirements from structure, properties, and processes to crew health and protection for exploration missions.

Triboluminescent Materials for Smart Optical Damage Sensors for Space Applications

NASA Technical Reports Server (NTRS)

Aggarwal, Mohan D.; Penn, Benjamin G.; Miller, Jim

2007-01-01

Triboluminescence is light that is produced by pressure, friction or mechanical shock. New composite materials are constantly being reengi neered in an effort to make lightweight spacecrafts for various NASA missions. For these materials there is interest in monitoring the con dition of the composite in real time to detect any delamination or cr acking due to damage, fatigue or external forces. Methods of periodic inspection of composite structures for mechanical damage such as ult rasonic testing are rather mature. However, there is a need to develop a new technique of damage detection for composites, which could dete ct cracking or delamination from any desired location within a materi al structure in real time. This could provide a valuable tool in the confident use of composite materials for various space applications. Recently, triboluminnescent materials have been proposed as smart sen sors of structural damage. To sense the damage, these materials can b e epoxy bonded or coated in a polymer matrix or embedded in a composi te host structure. When the damage or fracture takes place in the hos t structure, it will lead to the fracture of triboluminescent crystal s resulting in a light emission. This will warn, in real time, that a structural damage has occurred. The triboluminescent emission of the candidate phosphor has to be sufficiently bright, so that the light signal reaching from the point of fracture to the detector through a fiber optic cable is sufficiently strong to be detected. There are a large number of triboluminescent materials, but few satisfy the above criterion. Authors have synthesized a Eu based organic material know n as Europium tetrakis (dibenzoylmethide) triethylammonium .(EuD(sub 4)TEA), one of the bright triboluminescent materials, which is a pote ntial candidate for application as a damage sensor and could be made into a wireless sensor with the addition of microchip, antenna and el ectronics. Preliminary results on the synthesis and characterization of this material shall be presented.

Intraply Hybrid Composites Would Contain Control Strips

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Shiao, Chi-Yu

1996-01-01

"Smart" structural components with sensors and/or actuators distributed throughout their volumes made of intraply hybrid composite materials, according to proposal. Strips of hybrid control material interspersed with strips of ordinary (passive) composite material in some layers, providing distributed control capability. For example, near and far edges of plate bent upward by commanding bottom control strips to expand and simultaneously commanding upper control strips to contract.

Scale-up of nature's tissue weaving algorithms to engineer advanced functional materials.

PubMed

Ng, Joanna L; Knothe, Lillian E; Whan, Renee M; Knothe, Ulf; Tate, Melissa L Knothe

2017-01-11

We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently "smart" material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues' biological, mechanical and organizational detail to create advanced functional materials. Here, a novel approach is established to scale up the multidimensional fiber patterns of natural soft tissue weaves for rapid prototyping of advanced functional materials. First second harmonic generation and two-photon excitation microscopy is used to map the microscopic three-dimensional (3D) alignment, composition and distribution of the collagen and elastin fibers of periosteum, the soft tissue sheath bounding all nonarticular bone surfaces in our bodies. Then, using engineering rendering software to scale up this natural tissue fabric, as well as multidimensional weaving algorithms, macroscopic tissue prototypes are created using a computer-controlled jacquard loom. The capacity to prototype scaled up architectures of natural fabrics provides a new avenue to create advanced functional materials.

Biosmart Materials: Breaking New Ground in Dentistry

PubMed Central

Badami, Vijetha; Ahuja, Bharat

2014-01-01

By definition and general agreement, smart materials are materials that have properties which may be altered in a controlled fashion by stimuli, such as stress, temperature, moisture, pH, and electric or magnetic fields. There are numerous types of smart materials, some of which are already common. Examples include piezoelectric materials, which produce a voltage when stress is applied or vice versa, shape memory alloys or shape memory polymers which are thermoresponsive, and pH sensitive polymers which swell or shrink as a response to change in pH. Thus, smart materials respond to stimuli by altering one or more of their properties. Smart behaviour occurs when a material can sense some stimulus from its environment and react to it in a useful, reliable, reproducible, and usually reversible manner. These properties have a beneficial application in various fields including dentistry. Shape memory alloys, zirconia, and smartseal are examples of materials exhibiting a smart behavior in dentistry. There is a strong trend in material science to develop and apply these intelligent materials. These materials would potentially allow new and groundbreaking dental therapies with a significantly enhanced clinical outcome of treatments. PMID:24672407

The Effect of 4-Octyldecyloxybenzoic Acid on Liquid-Crystalline Polyurethane Composites with Triple-Shape Memory and Self-Healing Properties

PubMed Central

Ban, Jianfeng; Zhu, Linjiang; Chen, Shaojun; Wang, Yiping

2016-01-01

To better understand shape memory materials and self-healing materials, a new series of liquid-crystalline shape memory polyurethane (LC-SMPU) composites, named SMPU-OOBAm, were successfully prepared by incorporating 4-octyldecyloxybenzoic acid (OOBA) into the PEG-based SMPU. The effect of OOBA on the structure, morphology, and properties of the material has been carefully investigated. The results demonstrate that SMPU-OOBAm has liquid crystalline properties, triple-shape memory properties, and self-healing properties. The incorporated OOBA promotes the crystallizability of both soft and hard segments of SMPU, and the crystallization rate of the hard segment of SMPU decreases when the OOBA-content increases. Additionally, the SMPU-OOBAm forms a two-phase separated structure (SMPU phase and OOBA phase), and it shows two-step modulus changes upon heating. Therefore, the SMPU-OOBAm exhibits triple-shape memory behavior, and the shape recovery ratio decreases with an increase in the OOBA content. Finally, SMPU-OOBAm exhibits self-healing properties. The new mechanism can be ascribed to the heating-induced “bleeding” of OOBA in the liquid crystalline state and the subsequent re-crystallization upon cooling. This successful combination of liquid crystalline properties, triple-shape memory properties, and self-healing properties make the SMPU-OOBAm composites ideal for many promising applications in smart optical devices, smart electronic devices, and smart sensors. PMID:28773914

Structural vibration-based damage classification of delaminated smart composite laminates

NASA Astrophysics Data System (ADS)

Khan, Asif; Kim, Heung Soo; Sohn, Jung Woo

2018-03-01

Separation along the interfaces of layers (delamination) is a principal mode of failure in laminated composites and its detection is of prime importance for structural integrity of composite materials. In this work, structural vibration response is employed to detect and classify delaminations in piezo-bonded laminated composites. Improved layerwise theory and finite element method are adopted to develop the electromechanically coupled governing equation of a smart composite laminate with and without delaminations. Transient responses of the healthy and damaged structures are obtained through a surface bonded piezoelectric sensor by solving the governing equation in the time domain. Wavelet packet transform (WPT) and linear discriminant analysis (LDA) are employed to extract discriminative features from the structural vibration response of the healthy and delaminated structures. Dendrogram-based support vector machine (DSVM) is used to classify the discriminative features. The confusion matrix of the classification algorithm provided physically consistent results.

A new SMART sensing system for aerospace structures

NASA Astrophysics Data System (ADS)

Zhang, David C.; Yu, Pin; Beard, Shawn; Qing, Peter; Kumar, Amrita; Chang, Fu-Kuo

2007-04-01

It is essential to ensure the safety and reliability of in-service structures such as unmanned vehicles by detecting structural cracking, corrosion, delamination, material degradation and other types of damage in time. Utilization of an integrated sensor network system can enable automatic inspection of such damages ultimately. Using a built-in network of actuators and sensors, Acellent is providing tools for advanced structural diagnostics. Acellent's integrated structural health monitoring system consists of an actuator/sensor network, supporting signal generation and data acquisition hardware, and data processing, visualization and analysis software. This paper describes the various features of Acellent's latest SMART sensing system. The new system is USB-based and is ultra-portable using the state-of-the-art technology, while delivering many functions such as system self-diagnosis, sensor diagnosis, through-transmission mode and pulse-echo mode of operation and temperature measurement. Performance of the new system was evaluated for assessment of damage in composite structures.

Analysis of Sensory/Active Piezoelectric Composite Structures in Thermal Environments

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun; Saravanos, Dimitris A.

1996-01-01

Although there has been extensive development of analytical methods for modeling the behavior of piezoelectric structures, only a limited amount of research has been performed concerning the implications of thermal effects on both the active and sensory response of smart structures. Thermal effects become important when the piezoelectric structure has to operate in either extremely hot or cold temperature environments. Consequently, the purpose of this paper is to extend the previously developed discrete layer formulation of Saravanos and Heyliger to account for the coupled mechanical, electrical, and thermal response in modern smart composite beams. The mechanics accounts for thermal effects which may arise in the elastic and piezoelectric media at the material level through the constitutive equations. The displacements, electric potentials, and temperatures are introduced as state variables, allowing them to be modeled as variable fields through the laminate thickness. This unified representation leads to an inherent capability to model both the active compensation of thermal distortions in smart structures and the resultant sensory voltage when thermal loads are applied. The corresponding finite element formulation is developed and numerical results demonstrate the ability to model both the active and sensory modes of composite beams with heterogeneous plies with attached piezoelectric layers under thermal loadings.

Concepts for smart nanocomposite materials

NASA Astrophysics Data System (ADS)

Pammi, SriLaxmi; Brown, Courtney; Datta, Saurabh; Kirikera, Goutham R.; Schulz, Mark J.

2003-10-01

This paper explores concepts for new smart materials that have extraordinary properties based on nanotechnology. Carbon and boron nitride nanotubes in theory can be used to manufacture fibers that have piezoelectric, pyroelectric, piezoresistive, and electrochemical field properties. Smart nanocomposites designed using these fibers will sense and respond to elastic, thermal, and chemical fields in a positive human-like way to improve the performance of structures, devices, and possibly humans. Remarkable strength, morphing, cooling, energy harvesting, strain and temperature sensing, chemical sensing and filtering, and high natural frequencies and damping will be the properties of these new materials. Synthesis of these unique atomically precise nanotubes, fibers, and nanocomposites is at present challenging and expensive, however, there is the possibility that we can synthesize the strongest and lightest actuators and most efficient sensors man has ever made. A particular advantage of nanotube transducers is their very high load bearing capability. Carbon nanotube electrochemical actuators have a predicted energy density at low frequencies that is thirty times greater than typical piezoceramic materials while boron nitride nanotubes are insulators and can operate at high temperatures, but they have a predicted piezoelectric induced stress constant that is about twenty times smaller than piezoceramic materials. Carbon nanotube fibers and composites exhibit a change in electrical conductivity due to strain that can be used for sensing. Some concepts for nanocomposite material sensors are presented and initial efforts to fabricate carbon nanocomposite load sensors are discussed.

SMART Layer and SMART Suitcase for structural health monitoring applications

NASA Astrophysics Data System (ADS)

Lin, Mark; Qing, Xinlin; Kumar, Amrita; Beard, Shawn J.

2001-06-01

Knowledge of integrity of in-service structures can greatly enhance their safety and reliability and lower structural maintenance cost. Current practices limit the extent of real-time knowledge that can be obtained from structures during inspection, are labor-intensive and thereby increase life-cycle costs. Utilization of distributed sensors integrated with the structure is a viable and cost-effective means of monitoring the structure and reducing inspection costs. Acellent Technologies is developing a novel system for actively and passively interrogating the health of a structure through an integrated network of sensors and actuators. Acellent's system comprises of SMART Layers, SMART Suitcase and diagnostic software. The patented SMART Layer is a thin dielectric film with an embedded network of distributed piezoelectric actuators/sensors that can be surface-mounted on metallic structures or embedded inside composite structures. The SMART Suitcase is a portable diagnostic unit designed with multiple sensor/actuator channels to interface with the SMART Layer, generate diagnostic signals from actuators and record measurements from the embedded sensors. With appropriate diagnostic software, Acellent's system can be used for monitoring structural condition and for detecting damage while the structures are in service. This paper enumerates on the SMART Layer and SMART Suitcase and their applicability to composite and metal structures.

Transparent optically vanadium dioxide thermochromic smart film fabricated via electrospinning technique

NASA Astrophysics Data System (ADS)

Lu, Yuan; Xiao, Xiudi; Cao, Ziyi; Zhan, Yongjun; Cheng, Haoliang; Xu, Gang

2017-12-01

The monoclinic phase vanadium dioxide VO2 (M) based transparent thermochromic smart films were firstly fabricated through heat treatment of opaque VO2-based composite nanofibrous mats, which were deposited on the glass substrate via electrospinning technique. Noteworthily, the anti-oxidation property of VO2 smart film was improved due to inner distribution of VO2 in the polymethylmethacrylate (PMMA) nanofibers, and the composite mats having water contact angle of 165° determined itself good superhydrophobic property. Besides, PMMA nanofibrous mats with different polymer concentrations demonstrated changeable morphology and fiber diameter. The VO2 nanoparticles having diameter of 30-50 nm gathered and exhibited ellipse-like or belt-like structure. Additionally, the solar modulation ability of PMMA-VO2 composite smart film was 6.88% according to UV-Vis-NIR spectra. The research offered a new notion for fabricating transparent VO2 thermochromic material.

Spline Approximation of Thin Shell Dynamics

NASA Technical Reports Server (NTRS)

delRosario, R. C. H.; Smith, R. C.

1996-01-01

A spline-based method for approximating thin shell dynamics is presented here. While the method is developed in the context of the Donnell-Mushtari thin shell equations, it can be easily extended to the Byrne-Flugge-Lur'ye equations or other models for shells of revolution as warranted by applications. The primary requirements for the method include accuracy, flexibility and efficiency in smart material applications. To accomplish this, the method was designed to be flexible with regard to boundary conditions, material nonhomogeneities due to sensors and actuators, and inputs from smart material actuators such as piezoceramic patches. The accuracy of the method was also of primary concern, both to guarantee full resolution of structural dynamics and to facilitate the development of PDE-based controllers which ultimately require real-time implementation. Several numerical examples provide initial evidence demonstrating the efficacy of the method.

Continuous and embedded solutions for SHM of concrete structures using changing electrical potential in self-sensing cement-based composites

NASA Astrophysics Data System (ADS)

Downey, Austin; Garcia-Macias, Enrique; D'Alessandro, Antonella; Laflamme, Simon; Castro-Triguero, Rafael; Ubertini, Filippo

2017-04-01

Interest in the concept of self-sensing structural materials has grown in recent years due to its potential to enable continuous low-cost monitoring of next-generation smart-structures. The development of cement-based smart sensors appears particularly well suited for monitoring applications due to their numerous possible field applications, their ease of use and long-term stability. Additionally, cement-based sensors offer a unique opportunity for structural health monitoring of civil structures because of their compatibility with new or existing infrastructure. Particularly, the addition of conductive carbon nanofillers into a cementitious matrix provides a self-sensing structural material with piezoresistive characteristics sensitive to deformations. The strain-sensing ability is achieved by correlating the external loads with the variation of specific electrical parameters, such as the electrical resistance or impedance. Selection of the correct electrical parameter for measurement to correlate with features of interest is required for the condition assessment task. In this paper, we investigate the potential of using altering electrical potential in cement-based materials doped with carbon nanotubes to measure strain and detect damage in concrete structures. Experimental validation is conducted on small-scale specimens including a steel-reinforced beam of conductive cement paste. Comparisons are made with constant electrical potential and current methods commonly found in the literature. Experimental results demonstrate the ability of the changing electrical potential at detecting features important for assessing the condition of a structure.

Kirigami design and fabrication for biomimetic robotics

NASA Astrophysics Data System (ADS)

Rossiter, Jonathan; Sareh, Sina

2014-03-01

Biomimetics faces a continual challenge of how to bridge the gap between what Nature has so effectively evolved and the current tools and materials that engineers and scientists can exploit. Kirigami, from the Japanese `cut' and `paper', is a method of design where laminar materials are cut and then forced out-of-plane to yield 3D structures. Kirimimetic design provides a convenient and relatively closed design space within which to replicate some of the most interesting niche biological mechanisms. These include complex flexing organelles such as cilia in algae, energy storage and buckled structures in plants, and organic appendages that actuate out-of-plane such as the myoneme of the Vorticella protozoa. Where traditional kirigami employs passive materials which must be forced to transition to higher dimensions, we can exploit planar smart actuators and artificial muscles to create self-actuating kirigami structures. Here we review biomimetics with respect to the kirigami design and fabrication methods and examine how smart materials, including electroactive polymers and shape memory polymers, can be used to realise effective biomimetic components for robotic, deployable structures and engineering systems. One-way actuation, for example using shape memory polymers, can yield complete self-deploying structures. Bi-directional actuation, in contrast, can be exploited to mimic fundamental biological mechanisms such as thrust generation and fluid control. We present recent examples of kirigami robotic mechanisms and actuators and discuss planar fabrication methods, including rapid prototyping and 3D printing, and how current technologies, and their limitations, affect Kirigami robotics.

Market-Smart Deconstruction and Material Recovery at Brownfield Sites: How to Identify and Reuse Existing Materials Found at Brownfield Sites

DTIC Science & Technology

2011-06-01

efforts to assess , remediate, and sustainably reuse brownfields . This project is based on the premise that communities have finite resources and that the...this work is to develop tools and guidance for brownfields partners to assess the potential of extracting construction material assets from...buildings, structures, and infrastructure on brownfield sites, and to reuse or recycle this material. This assessment will address the physical

Modeling of a reinforced concrete beam using shape memory alloy as reinforcement bars

NASA Astrophysics Data System (ADS)

Bajoria, Kamal M.; Kaduskar, Shreya S.

2017-04-01

In this paper the structural behavior of reinforced concrete (RC) beams with smart rebars under three point loading system has been numerically studied, using Finite Element Method. The material used in this study is Superelastic Shape Memory Alloy (SE SMA) which contains nickel and titanium. Shape memory alloys (SMAs) are a unique class of materials which have ability to undergo large deformation and also regain their un-deformed shape by removal of stress or by heating. In this study, a uniaxial SMA model is able to reproduce the pseudo-elastic behavior for the reinforcing SMA wires. Finite element simulation is developed in order to study the load-deflection behavior of smart concrete beams subjected to three-point bending tests.

Microstructured Optical Fiber Sensors Embedded in a Laminate Composite for Smart Material Applications

PubMed Central

Sonnenfeld, Camille; Sulejmani, Sanne; Geernaert, Thomas; Eve, Sophie; Lammens, Nicolas; Luyckx, Geert; Voet, Eli; Degrieck, Joris; Urbanczyk, Waclaw; Mergo, Pawel; Becker, Martin; Bartelt, Hartmut; Berghmans, Francis; Thienpont, Hugo

2011-01-01

Fiber Bragg gratings written in highly birefringent microstructured optical fiber with a dedicated design are embedded in a composite fiber-reinforced polymer. The Bragg peak wavelength shifts are measured under controlled axial and transversal strain and during thermal cycling of the composite sample. We obtain a sensitivity to transversal strain that exceeds values reported earlier in literature by one order of magnitude. Our results evidence the relevance of using microstructured optical fibers for structural integrity monitoring of composite material structures. PMID:22163755

Mechanical Response of Elastomers to Magnetic Fields

NASA Technical Reports Server (NTRS)

Munoz, B. C.; Jolly, M. R.

1996-01-01

Elastomeric materials represent an important class of engineering materials, which are widely used to make components of structures, machinery, and devices for vibration and noise control. Elastomeric material possessing conductive or magnetic properties have been widely used in applications such as conductive and magnetic tapes, sensors, flexible permanent magnets, etc. Our interest in these materials has focussed on understanding and controlling the magnitude and directionality of their response to applied magnetic fields. The effect of magnetic fields on the mechanical properties of these materials has not been the subject of many published studies. Our interest and expertise in controllable fluids have given us the foundation to make a transition to controllable elastomers. Controllable elastomers are materials that exhibit a change in mechanical properties upon application of an external stimuli, in this case a magnetic field. Controllable elastomers promise to have more functionality than conventional elastomers and therefore could share the broad industrial application base with conventional elastomers. As such, these materials represent an attractive class of smart materials, and may well be a link that brings the applications of modern control technologies, intelligent structures and smart materials to a very broad industrial area. This presentation will cover our research work in the area of controllable elastomers at the Thomas Lord Research Center. More specifically, the presentation will discuss the control of mechanical properties and mathematical modeling of the new materials prepared in our laboratories along with experiments to achieve adaptive vibration control using the new materials.

Boeing Smart Rotor Full-scale Wind Tunnel Test Data Report

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi; Hagerty, Brandon; Salazar, Denise

2016-01-01

A full-scale helicopter smart material actuated rotor technology (SMART) rotor test was conducted in the USAF National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel at NASA Ames. The SMART rotor system is a five-bladed MD 902 bearingless rotor with active trailing-edge flaps. The flaps are actuated using piezoelectric actuators. Rotor performance, structural loads, and acoustic data were obtained over a wide range of rotor shaft angles of attack, thrust, and airspeeds. The primary test objective was to acquire unique validation data for the high-performance computing analyses developed under the Defense Advanced Research Project Agency (DARPA) Helicopter Quieting Program (HQP). Other research objectives included quantifying the ability of the on-blade flaps to achieve vibration reduction, rotor smoothing, and performance improvements. This data set of rotor performance and structural loads can be used for analytical and experimental comparison studies with other full-scale rotor systems and for analytical validation of computer simulation models. The purpose of this final data report is to document a comprehensive, highquality data set that includes only data points where the flap was actively controlled and each of the five flaps behaved in a similar manner.

TOPICAL REVIEW: Smart aggregates: multi-functional sensors for concrete structures—a tutorial and a review

NASA Astrophysics Data System (ADS)

Song, Gangbing; Gu, Haichang; Mo, Yi-Lung

2008-06-01

This paper summarizes the authors' recent pioneering research work in piezoceramic-based smart aggregates and their innovative applications in concrete civil structures. The basic operating principle of smart aggregates is first introduced. The proposed smart aggregate is formed by embedding a waterproof piezoelectric patch with lead wires into a small concrete block. The proposed smart aggregates are multi-functional and can perform three major tasks: early-age concrete strength monitoring, impact detection and structural health monitoring. The proposed smart aggregates are embedded into the desired location before the casting of the concrete structure. The concrete strength development is monitored by observing the high frequency harmonic wave response of the smart aggregate. Impact on the concrete structure is detected by observing the open-circuit voltage of the piezoceramic patch in the smart aggregate. For structural health monitoring purposes, a smart aggregate-based active sensing system is designed for the concrete structure. Wavelet packet analysis is used as a signal-processing tool to analyze the sensor signal. A damage index based on the wavelet packet analysis is used to determine the structural health status. To better describe the time-history and location information of damage, two types of damage index matrices are proposed: a sensor-history damage index matrix and an actuator-sensor damage index matrix. To demonstrate the multi-functionality of the proposed smart aggregates, different types of concrete structures have been used as test objects, including concrete bridge bent-caps, concrete cylinders and a concrete frame. Experimental results have verified the effectiveness and the multi-functionality of the proposed smart aggregates. The multi-functional smart aggregates have the potential to be applied to the comprehensive monitoring of concrete structures from their earliest stages and throughout their lifetime.

Biomining of MoS2 with Peptide-based Smart Biomaterials.

PubMed

Cetinel, Sibel; Shen, Wei-Zheng; Aminpour, Maral; Bhomkar, Prasanna; Wang, Feng; Borujeny, Elham Rafie; Sharma, Kumakshi; Nayebi, Niloofar; Montemagno, Carlo

2018-02-20

Biomining of valuable metals using a target specific approach promises increased purification yields and decreased cost. Target specificity can be implemented with proteins/peptides, the biological molecules, responsible from various structural and functional pathways in living organisms by virtue of their specific recognition abilities towards both organic and inorganic materials. Phage display libraries are used to identify peptide biomolecules capable of specifically recognizing and binding organic/inorganic materials of interest with high affinities. Using combinatorial approaches, these molecular recognition elements can be converted into smart hybrid biomaterials and harnessed for biotechnological applications. Herein, we used a commercially available phage-display library to identify peptides with specific binding affinity to molybdenite (MoS 2 ) and used them to decorate magnetic NPs. These peptide-coupled NPs could capture MoS 2 under a variety of environmental conditions. The same batch of NPs could be re-used multiple times to harvest MoS 2 , clearly suggesting that this hybrid material was robust and recyclable. The advantages of this smart hybrid biomaterial with respect to its MoS 2 -binding specificity, robust performance under environmentally challenging conditions and its recyclability suggests its potential application in harvesting MoS 2 from tailing ponds and downstream mining processes.

Piezoresistive strain sensing of carbon nanotubes-based composite skin for aeronautical morphing structures

NASA Astrophysics Data System (ADS)

Viscardi, Massimo; Arena, Maurizio; Barra, Giuseppina; Vertuccio, Luigi; Ciminello, Monica; Guadagno, Liberata

2018-03-01

Nowadays, smart composites based on different nano-scale carbon fillers, such as carbon nanotubes (CNTs), are increasingly being thought of as a more possible alternative solution to conventional smart materials, mainly for their improved electrical properties. Great attention is being given by the research community in designing highly sensitive strain sensors for more and more ambitious challenges: in such context, interest fields related to carbon nanotubes have seen extraordinary development in recent years. The authors aim to provide the most contemporary overview possible of carbon nanotube-based strain sensors for aeronautical application. A smart structure as a morphing wing needs an embedded sensing system in order to measure the actual deformation state as well as to "monitor" the structural conditions. Looking at more innovative health monitoring tools for the next generation of composite structures, a resin strain sensor has been realized. The epoxy resin was first analysed by means of a micro-tension test, estimating the electrical resistance variations as function of the load, in order to demonstrate the feasibility of the sensor. The epoxy dogbone specimen has been equipped with a standard strain gauge to quantify its strain sensitivity. The voltamperometric tests highlight a good linearity of the electrical resistance value as the load increases at least in the region of elastic deformation of the material. Such intrinsic piezoresistive performance is essentially attributable to the re-arrangement of conductive percolating network formed by MWCNT, induced by the deformation of the material due to the applied loads. The specimen has been prepared within this investigation, to demonstrate its performance for a future composite laminate typical of aerospace structures. The future carbon-fiber sensor can replace conventional metal foil strain gauges in aerospace applications. Furthermore, dynamic tests will be carried out to detect any non-reversible changes to the sensing response.

Preliminary Structural Sizing and Alternative Material Trade Study of CEV Crew Module

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Arnold, Steve M.; Collier, Craig S.; Yarrington, Phillip W.

2007-01-01

This paper presents the results of a preliminary structural sizing and alternate material trade study for NASA s Crew Exploration Vehicle (CEV) Crew Module (CM). This critical CEV component will house the astronauts during ascent, docking with the International Space Station, reentry, and landing. The alternate material design study considers three materials beyond the standard metallic (aluminum alloy) design that resulted from an earlier NASA Smart Buyer Team analysis. These materials are graphite/epoxy composite laminates, discontinuously reinforced SiC/Al (DRA) composites, and a novel integrated panel material/concept known as WebCore. Using the HyperSizer (Collier Research and Development Corporation) structural sizing software and NASTRAN finite element analysis code, a comparison is made among these materials for the three composite CM concepts considered by the 2006 NASA Engineering and Safety Center Composite Crew Module project.

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings

PubMed Central

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-01-01

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating. PMID:23546301

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings.

PubMed

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-01-01

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating.

Proceedings of the 4th Annual Workshop: Advances in Smart Materials for Aerospace Applications

NASA Technical Reports Server (NTRS)

Hardy, Robin C. (Editor); Simpson, Joycelyn O. (Editor)

1996-01-01

The objective of the Fourth Annual Conference on Advances in Smart Materials for Aerospace Applications was to provide a forum for technical dialogue on numerous topics in the area of smart materials. The proceedings presented herein represent the technical contributions of the participants of the workshop. Topics addressed include shape memory alloys, ferroelectrics, fiber optics, finite element simulation, and active control.

Prototype Morphing Fan Nozzle Demonstrated

NASA Technical Reports Server (NTRS)

Lee, Ho-Jun; Song, Gang-Bing

2004-01-01

Ongoing research in NASA Glenn Research Center's Structural Mechanics and Dynamics Branch to develop smart materials technologies for aeropropulsion structural components has resulted in the design of the prototype morphing fan nozzle shown in the photograph. This prototype exploits the potential of smart materials to significantly improve the performance of existing aircraft engines by introducing new inherent capabilities for shape control, vibration damping, noise reduction, health monitoring, and flow manipulation. The novel design employs two different smart materials, a shape-memory alloy and magnetorheological fluids, to reduce the nozzle area by up to 30 percent. The prototype of the variable-area fan nozzle implements an overlapping spring leaf assembly to simplify the initial design and to provide ease of structural control. A single bundle of shape memory alloy wire actuators is used to reduce the nozzle geometry. The nozzle is subsequently held in the reduced-area configuration by using magnetorheological fluid brakes. This prototype uses the inherent advantages of shape memory alloys in providing large induced strains and of magnetorheological fluids in generating large resistive forces. In addition, the spring leaf design also functions as a return spring, once the magnetorheological fluid brakes are released, to help force the shape memory alloy wires to return to their original position. A computerized real-time control system uses the derivative-gain and proportional-gain algorithms to operate the system. This design represents a novel approach to the active control of high-bypass-ratio turbofan engines. Researchers have estimated that such engines will reduce thrust specific fuel consumption by 9 percent over that of fixed-geometry fan nozzles. This research was conducted under a cooperative agreement (NCC3-839) at the University of Akron.

Aeroelastic Tailoring of Transport Aircraft Wings: State-of-the-Art and Potential Enabling Technologies

NASA Technical Reports Server (NTRS)

Jutte, Christine; Stanford, Bret K.

2014-01-01

This paper provides a brief overview of the state-of-the-art for aeroelastic tailoring of subsonic transport aircraft and offers additional resources on related research efforts. Emphasis is placed on aircraft having straight or aft swept wings. The literature covers computational synthesis tools developed for aeroelastic tailoring and numerous design studies focused on discovering new methods for passive aeroelastic control. Several new structural and material technologies are presented as potential enablers of aeroelastic tailoring, including selectively reinforced materials, functionally graded materials, fiber tow steered composite laminates, and various nonconventional structural designs. In addition, smart materials and structures whose properties or configurations change in response to external stimuli are presented as potential active approaches to aeroelastic tailoring.

Modelling, fabrication, and characterization for improved piezoelectric energy harvesters

NASA Astrophysics Data System (ADS)

Alomari, Almuatasim Ali

The ambitious goal of this dissertation is to contribute its share to the scientific researchers and academic community by demonstrate a versatile study on energy harvesting via smart materials. Smart materials are amongst the current production modes which generate clean and green energy. The advantages of smart materials include ferroelectric, piezoelectric, and pyroelectric ceramics and composites in materials science and technology of the 21 st century are inconceivable. Their most current applications include conventional sensors, actuators, batteries replacement, and switch. Further, Piezoelectricity is the accumulation of electrical charges as a result of applying mechanical stress on certain type of materials such as crystals, DNA, and protein, where pyro-electricity is the accumulation of electrical charges from ambient environment from temperature gauges or fluctuations. In an incessant effort to increase the performance of smart materials devices researchers in both academic and industrial communities in field of green energy have suggested many techniques and procedures to increase the power generation capability and enhance the bandwidth of thermal and vibration energy harvesters. In this study, the EulerBernoulli beam Theory, lumped parameter model (LPM), and chain matrix method were applied on various design and structure shape of smart materials to find the output electrical parameters. The modeling and simulation investigations are accomplished using MATLAB program and COMSOL Multiphysics software. A low-cost fabrication technique, of polyvinyl-dine difluoride (PVDF) with different amount of Lead Zirconate Titanate (PZT), Lead Magnesium Niobate-Lead Titanate (PMN-PT), and Multi-walled Carbon Nanotubes (MWCNT) are introduced in this study as well. Later, the (Paint/ PZT) fabricated nanocomposites was tested for dielectric constants over a wide frequency range at different temperatures. It was observed that the composites with higher concentrations of PZT nanocomposite have higher dielectric constants than well-known PVDF film. Finally, the performance of the piezoelectric and pyroelectric PMN-PT single crystal with a (67:33) composition grown in our laboratory using unimorph device structures was evaluated via modeling and experiments. The theoretical study was implemented based on a distributed parameter electromechanical model and the modelling procedure was approximated using the finite element analysis (FEA) to predict the electromechanical behavior of the harvesters. The maximum power density at a resonance frequency of 65 Hz and optimum resistance of 200 kO was 45 nW under a 0.5 g acceleration of vibration. By using pyroelectric effect along with the piezoelectric effect, the output voltage of the energy harvester was found to be enhanced at the optimum resistance and specific frequency values. It was noticed that the output voltage was increased monotonically with temperature-difference (DeltaT) and reaches up to 180% of its original value under difference temperature of 1.7 °C.

Computational smart polymer design based on elastin protein mutability.

PubMed

Tarakanova, Anna; Huang, Wenwen; Weiss, Anthony S; Kaplan, David L; Buehler, Markus J

2017-05-01

Soluble elastin-like peptides (ELPs) can be engineered into a range of physical forms, from hydrogels and scaffolds to fibers and artificial tissues, finding numerous applications in medicine and engineering as "smart polymers". Elastin-like peptides are attractive candidates as a platform for novel biomaterial design because they exhibit a highly tunable response spectrum, with reversible phase transition capabilities. Here, we report the design of the first virtual library of elastin-like protein models using methods for enhanced sampling to study the effect of peptide chemistry, chain length, and salt concentration on the structural transitions of ELPs, exposing associated molecular mechanisms. We describe the behavior of the local molecular structure under increasing temperatures and the effect of peptide interactions with nearest hydration shell water molecules on peptide mobility and propensity to exhibit structural transitions. Shifts in the magnitude of structural transitions at the single-molecule scale are explained from the perspective of peptide-ion-water interactions in a library of four unique elastin-like peptide systems. Predictions of structural transitions are subsequently validated in experiment. This library is a valuable resource for recombinant protein design and synthesis as it elucidates mechanisms at the single-molecule level, paving a feedback path between simulation and experiment for smart material designs, with applications in biomedicine and diagnostic devices. Copyright © 2017. Published by Elsevier Ltd.

Wafer-Level Vacuum Packaging of Smart Sensors

PubMed Central

Hilton, Allan; Temple, Dorota S.

2016-01-01

The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors—“low cost” for ubiquitous presence, and “smart” for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology. PMID:27809249

Payload Isolation System for Launch Vehicles

DTIC Science & Technology

1997-03-01

Payload Isolation System for Launch Vehicles Paul S. Wilke, Conor D. Johnson CSA Engineering Palo Alto, CA Eugene R. Fosness Air Force Phillips ... Laboratory , PL/VTVD Kirkland AFB, NM Spie Smart Structures and Materials San Diego, CA March 1997 Copyright 1997 Society of Photo-Optical Instrumentation

Mechanism study of biopolymer hair as a coupled thermo-water responsive smart material

NASA Astrophysics Data System (ADS)

Xiao, Xueliang; Zhou, Hongtao; Qian, Kun

2017-03-01

Animal hairs existing broadly in nature are found to be effectively responsive to stimuli of heat and water in sequence for shape deformation and recovery, namely, coupled shape memory function (CSMF). In the paper, the ability of thermo-water sensitive CSMF was first time investigated for animal hairs, the structural and molecular networks for net-points and switches were therefrom identified. Experimentally, animal hair manifested a high ability of shape fixation in thermal processing and good shape recovery by water stimulus. Characterizations of two stimuli (heating and hydration) were performed systematically on hair’s deformation, recovery, viscoelasticity and chemical components (crystalline phase, key bonds inamorphous area). The variations of related chemical components in molecular networks were also explored. A hybrid structural network model was thereafter proposed to interpret the thermo-water sensitive CSMF of hair. This study of two-sequential-stimuli CSMF is original and inspired to explore more complex functions of other smart natural materials and expected to make much smarter synthetic polymers.

Smart Materials Based on DNA Aptamers: Taking Aptasensing to the Next Level

PubMed Central

Mastronardi, Emily; Foster, Amanda; Zhang, Xueru; DeRosa, Maria C.

2014-01-01

“Smart” materials are an emerging category of multifunctional materials with physical or chemical properties that can be controllably altered in response to an external stimulus. By combining the standard properties of the advanced material with the unique ability to recognize and adapt in response to a change in their environment, these materials are finding applications in areas such as sensing and drug delivery. While the majority of these materials are responsive to physical or chemical changes, a particularly exciting area of research seeks to develop smart materials that are sensitive to specific molecular or biomolecular stimuli. These systems require the integration of a molecular recognition probe specific to the target molecule of interest. The ease of synthesis and labeling, low cost, and stability of DNA aptamers make them uniquely suited to effectively serve as molecular recognition probes in novel smart material systems. This review will highlight current work in the area of aptamer-based smart materials and prospects for their future applications. PMID:24553083

Renewable smart materials

NASA Astrophysics Data System (ADS)

Kim, Hyun Chan; Mun, Seongcheol; Ko, Hyun-U.; Zhai, Lindong; Kafy, Abdullahil; Kim, Jaehwan

2016-07-01

The use of renewable materials is essential in future technologies to harmonize with our living environment. Renewable materials can maintain our resources from the environment so as to overcome degradation of natural environmental services and diminished productivity. This paper reviews recent advancement of renewable materials for smart material applications, including wood, cellulose, chitin, lignin, and their sensors, actuators and energy storage applications. To further improve functionality of renewable materials, hybrid composites of inorganic functional materials are introduced by incorporating carbon nanotubes, titanium dioxide and tin oxide conducting polymers and ionic liquids. Since renewable materials have many advantages of biocompatible, sustainable, biodegradable, high mechanical strength and versatile modification behaviors, more research efforts need to be focused on the development of renewable smart materials.

Development of new smart materials and spinning systems inspired by natural silks and their applications

NASA Astrophysics Data System (ADS)

Cheng, Jie; Lee, Sang-Hoon

2015-12-01

Silks produced by spiders and silkworms are charming natural biological materials with highly optimized hierarchical structures and outstanding physicomechanical properties. The superior performance of silks relies on the integration of a unique protein sequence, a distinctive spinning process, and complex hierarchical structures. Silks have been prepared to form a variety of morphologies and are widely used in diverse applications, for example, in the textile industry, as drug delivery vehicles, and as tissue engineering scaffolds. This review presents an overview of the organization of natural silks, in which chemical and physical functions are optimized, as well as a range of new materials inspired by the desire to mimic natural silk structure and synthesis.

Smart Materials in Architecture: Useful Tools with Practical Applications or Fascinating Inventions for Experimental Design?

NASA Astrophysics Data System (ADS)

Konarzewska, Bogusława

2017-10-01

For at least several decades smart or so-called intelligent materials, being the result of great advancements in material engineering, appear in architecture in different applications. Most of them are called “smart” because of their inherent properties: a real-time response to environmental stimuli. There are also those considered to be “smart” due to smart design: their original structure or the composition of their materials are in nanoscale, providing them with unique properties. Colour changes, physical states, temperature or shape-always repeatable and reversible - make these materials attractive to architects, both from a visual and a practical point of view. Their spectacular applications often inspire architects, scientists and artists to create, for instance, city displays revealing various shapes and figures according to daily weather conditions; thermochromics urban seats that reflect peoples’ presence; wallpaper with organic patterns that glow in darkness, and many others. On the other hand, more practical projects are being developed, such as “switchable” partition glass walls (that is, we can turn them on and they change their transparency while switching on or off: electrochromic glass is a good example). Other concepts include self-cleaning building envelopes; self-repairing concrete; phase-changing materials diminishing cooling loads in the buildings; energy-generating highways; materials that harden at the moment of impact thus withstanding exceptionally great forces; shape memory alloys playing the role of actuators-opening and - closing façade louvers or thin polymer films mimicking the function of living skin, adopted as a building envelope. All those projects result from the fascination of designers with the possibility to create materials and, in effect, a complex environment that is active, “flexible”, and adapts to changing conditions and users’ needs and is compatible with real, natural environments. Smart materials that serve this purpose make such projects not only more unique and beautiful but, as their inventors claim, their application may bring real environmental and financial gains in the future. This article presents the most crucial, selected examples of such materials and examines what benefits they could offer.

Computer-aided applications of nanoscale smart materials for biomedical applications.

PubMed

Rakesh, L; Howell, B A; Chai, M; Mueller, A; Kujawski, M; Fan, D; Ravi, S; Slominski, C

2008-10-01

Nanotechnology has the potential to impact the treatment of many diseases that currently plague society: cancer, AIDS, dementia of various kinds and so on. Nanoscale smart materials, such as carbon nanotubes, C(60), dendrimers and cyclodextrins, hold great promise for use in the development of better diagnostics, drug delivery and the alteration of biological function. Although experimentation is being used to explore the potential offered by these materials, it is by its very nature expensive in terms of time, resources and expertise. Insight with respect to the behavior of these materials in the presence of biological entities can be obtained much more rapidly by molecular dynamics simulation. Furthermore, the results of simulation may be used to guide experimentation so that it is much more productive than it might be in the absence of such information. The interactions of several nanoscale structures with biological macromolecules can already be probed effectively using molecular dynamics simulation. The results obtained should form the basis for significant new developments in the treatment of disease.

Evolving application of biomimetic nanostructured hydroxyapatite

PubMed Central

Roveri, Norberto; Iafisco, Michele

2010-01-01

By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical–physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical–physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical–physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications. PMID:24198477

Review on developments in fiber optical sensors and applications

NASA Astrophysics Data System (ADS)

Annamdas, Kiran Kishore Kumar; Annamdas, Venu Gopal Madhav

2010-04-01

The last couple of decades had witnessed a rise in the research of optoelectronic and fiber optical communication fields, which resulted in applications focused initially in military and aerospace equipments, and later in health monitoring for medicine, heritage culture and various engineering fields. The monitoring of existing or /and new engineering, biomedical structures has become a regular feature throughout the world. Monitoring is fast emerging as a pioneering field with high precision and quality equipments. This field is very vast, consisting of both traditional as well as smart materials based methods. The fiber optics belong to the finest class of smart materials, there are many types and classifications based on the necessity, manufacturer and the end user. In this paper, a complete over view of fiber sensing systems and their usefulness is briefly presented.

Finite element analysis of electroactive polymer and magnetoactive elastomer based actuation for origami folding

NASA Astrophysics Data System (ADS)

Zhang, Wei; Ahmed, Saad; Masters, Sarah; Ounaies, Zoubeida; Frecker, Mary

2017-10-01

The incorporation of smart materials such as electroactive polymers and magnetoactive elastomers in origami structures can result in active folding using external electric and magnetic stimuli, showing promise in many origami-inspired engineering applications. In this study, 3D finite element analysis (FEA) models are developed using COMSOL Multiphysics software for three configurations that incorporate a combination of active and passive material layers, namely: (1) a single-notch unimorph folding configuration actuated using only external electric field, (2) a double-notch unimorph folding configuration actuated using only external electric field, and (3) a bifold configuration which is actuated using multi-field (electric and magnetic) stimuli. The objectives of the study are to verify the effectiveness of the FEA models to simulate folding behavior and to investigate the influence of geometric parameters on folding quality. Equivalent mechanical pressure and surface stress are used as external loads in the FEA to simulate electric and magnetic fields, respectively. Compared quantitatively with experimental data, FEA captured the folding performance of electric actuation well for notched configurations and magnetic actuation for a bifold structure, but underestimated electric actuation for the bifold structure. By investigating the impact of geometric parameters and locations to place smart materials, FEA can be used in design, avoiding trial-and-error iterations of experiments.

Damage suppression system using embedded SMA (shape memory alloy) foils in CFRP laminate structures

NASA Astrophysics Data System (ADS)

Ogisu, Toshimichi; Shimanuki, Masakazu; Kiyoshima, Satoshi; Takaki, Junji; Takeda, Nobuo

2003-08-01

This paper presents an overview of the demonstrator program with respect to the damage growth suppression effects using embedded SMA foils in CFRP laminates. The damage growth suppression effects were demonstrated for the technical verification in order to apply to aircraft structure. In our previous studies, the authors already confirmed the damage growth suppression effects of CFRP laminates with embedded pre-strained SMA foils through both coupon and structural element tests. It was founded that these effects were obtained by the suppression of the strain energy release rate based on the suppression of the crack opening displacement due to the recovery stress of SMA foils through the detail observation of the damage behavior. In this study, these results were verified using the demonstrator test article, which was 1/3-scaled model of commercial airliner fuselage structure. For the demonstration of damage growth suppression effects, the evaluation area was located in the lower panel, which was dominated in tension load during demonstration. The evaluation area is the integrated stiffened panel including both "smart area" (CFRP laminate with embedded pre-strained SMA foils) and "conventional area" (standard CFRP laminate) for the direct comparison. The demonstration was conducted at 80 degree Celsius in smart area and room temperature (RT) in conventional area during quasi-static load-unload test method. As the test results, the demonstrator test article presented that the damage onset strain in the smart area was improved by 30% for compared with the conventional area. Therefore, the successful technical verification of the damage onset/growth suppression effect using the demonstrator presented the feasibility of the application of smart material and structural system to aircraft structures.

Conductive polymer sensor arrays for smart orthopaedic implants

NASA Astrophysics Data System (ADS)

Micolini, Carolina; Holness, F. B.; Johnson, James A.; Price, Aaron D.

2017-04-01

This study proposes and demonstrates the design, implementation, and characterization of a 3D-printed smartpolymer sensor array using conductive polyaniline (PANI) structures embedded in a polymeric substrate. The piezoresistive characteristics of PANI were studied to evaluate the efficacy of the manufacturing of an embedded pressure sensor. PANI's stability throughout loading and unloading cycles together with the response to incremental loading cycles was investigated. It is demonstrated that this specially developed multi-material additive manufacturing process for polyaniline is a good candidate for the manufacture of implant components with smart-polymer sensors embedded for the analysis of joint loads in orthopaedic implants.

EDITORIAL: Greetings from the new Editor-in-Chief

NASA Astrophysics Data System (ADS)

Garcia, Ephrahim

2008-02-01

I am Professor Ephrahim Garcia, an Associate Professor at Sibley School of Mechanical and Aerospace Engineering at Cornell University in Ithaca, New York. I have been at Cornell University since 2002, spent four years as a Program Manager at the Defense Advanced Research Project Agency from 1998-2002, and before that seven years at the Department of Mechanical Engineering at Vanderbilt University in Nashville, Tennessee. I have served on the Editorial Advisory Board of Smart Materials and Structures (SMS) for the last six years. It is a humbling thing to be asked to take up the post of Editor-in-Chief in a field with so many talented researchers. I would like to say a heartfelt thanks to the members of the Editorial Board and IOP Publishing for their confidence in me. Most importantly, I would like to thank Professor Vijay Varadan of the University of Arkansas and Professor Richard Claus of Virginia Polytechnic Institute and State University for their efforts in launching the journal 16 years ago. They have been stewards, promoters and, especially Vijay, key to the operation and function of SMS for all these years, and our research community is indebted to them. Professors Varadan and Claus have dedicated their careers to the area of smart materials and structures and we are very grateful for their leadership, mentoring and contribution. SMS is a thriving journal offering papers on all technical areas concerned with smart materials, systems and structures from the micro- and nanoscale to the macroscale. The journal is undergoing some major changes, including the recent transferal of papers to IOP Publishing's peer-review management system. With this new system authors can expect fast publication times of around 4 or 5 months from submission, and excellent author service. In this world of ever changing technology, the Editorial Board and I aim to reduce the time to publication for researchers in this exciting area of science and engineering. I am in the process of developing a team of Associate Editors to promote the journal in the number of critical sub-areas of smart materials and structures, and to play a key, integral role in the review process. Associate Editors will be chosen to serve in a number of sub-areas to ensure expertise and continuation of the rigorous review process. Under my leadership as the new Editor-in-Chief of SMS, I aim to ensure that SMS maintains and grows in quality to best serve our diverse community of researchers.

Smart material-based radiation sources

NASA Astrophysics Data System (ADS)

Kovaleski, Scott

2014-10-01

From sensors to power harvesters, the unique properties of smart materials have been exploited in numerous ways to enable new applications and reduce the size of many useful devices. Smart materials are defined as materials whose properties can be changed in a controlled and often reversible fashion by use of external stimuli, such as electric and magnetic fields, temperature, or humidity. Smart materials have been used to make acceleration sensors that are ubiquitous in mobile phones, to make highly accurate frequency standards, to make unprecedentedly small actuators and motors, to seal and reduce friction of rotating shafts, and to generate power by conversion of either kinetic or thermal energy to electrical energy. The number of useful devices enabled by smart materials is large and continues to grow. Smart materials can also be used to generate plasmas and accelerate particles at small scales. The materials discussed in this talk are from non-centrosymmetric crystalline classes including piezoelectric, pyroelectric, and ferroelectric materials, which produce large electric fields in response to external stimuli such as applied electric fields or thermal energy. First, the use of ferroelectric, pyroelectric and piezoelectric materials for plasma generation and particle acceleration will be reviewed. The talk will then focus on the use of piezoelectric materials at the University of Missouri to construct plasma sources and electrostatic accelerators for applications including space propulsion, x-ray imaging, and neutron production. The basic concepts of piezoelectric transformers, which are analogous to conventional magnetic transformers, will be discussed, along with results from experiments over the last decade to produce micro-thrusters for space propulsion and particle accelerators for x-ray and neutron production. Support from ONR, AFOSR, and LANL.

Reversible Self-Actuated Thermo-Responsive Pore Membrane

PubMed Central

Park, Younggeun; Gutierrez, Maria Paz; Lee, Luke P.

2016-01-01

Smart membranes, which can selectively control the transfer of light, air, humidity and temperature, are important to achieve indoor climate regulation. Even though reversible self-actuation of smart membranes is desirable in large-scale, reversible self-regulation remains challenging. Specifically, reversible 100% opening/closing of pore actuation showing accurate responsiveness, reproducibility and structural flexibility, including uniform structure assembly, is currently very difficult. Here, we report a reversible, thermo-responsive self-activated pore membrane that achieves opening and closing of pores. The reversible, self-actuated thermo-responsive pore membrane was fabricated with hybrid materials of poly (N-isopropylacrylamide), (PNIPAM) within polytetrafluoroethylene (PTFE) to form a multi-dimensional pore array. Using Multiphysics simulation of heat transfer and structural mechanics based on finite element analysis, we demonstrated that pore opening and closing dynamics can be self-activated at environmentally relevant temperatures. Temperature cycle characterizations of the pore structure revealed 100% opening ratio at T = 40 °C and 0% opening ratio at T = 20 °C. The flexibility of the membrane showed an accurate temperature-responsive function at a maximum bending angle of 45°. Addressing the importance of self-regulation, this reversible self-actuated thermo-responsive pore membrane will advance the development of future large-scale smart membranes needed for sustainable indoor climate control. PMID:27991563

Reversible Self-Actuated Thermo-Responsive Pore Membrane

NASA Astrophysics Data System (ADS)

Park, Younggeun; Gutierrez, Maria Paz; Lee, Luke P.

2016-12-01

Smart membranes, which can selectively control the transfer of light, air, humidity and temperature, are important to achieve indoor climate regulation. Even though reversible self-actuation of smart membranes is desirable in large-scale, reversible self-regulation remains challenging. Specifically, reversible 100% opening/closing of pore actuation showing accurate responsiveness, reproducibility and structural flexibility, including uniform structure assembly, is currently very difficult. Here, we report a reversible, thermo-responsive self-activated pore membrane that achieves opening and closing of pores. The reversible, self-actuated thermo-responsive pore membrane was fabricated with hybrid materials of poly (N-isopropylacrylamide), (PNIPAM) within polytetrafluoroethylene (PTFE) to form a multi-dimensional pore array. Using Multiphysics simulation of heat transfer and structural mechanics based on finite element analysis, we demonstrated that pore opening and closing dynamics can be self-activated at environmentally relevant temperatures. Temperature cycle characterizations of the pore structure revealed 100% opening ratio at T = 40 °C and 0% opening ratio at T = 20 °C. The flexibility of the membrane showed an accurate temperature-responsive function at a maximum bending angle of 45°. Addressing the importance of self-regulation, this reversible self-actuated thermo-responsive pore membrane will advance the development of future large-scale smart membranes needed for sustainable indoor climate control.

Smart Materials, Structures, and Mathematical Issues for Active Damage Control

DTIC Science & Technology

1997-10-01

composites at both low and high velocities. The effect of low volume fractions (3% and 6%) of embedded Nitinol fibers on the impact-absorbing ability...ICI Wilton Materials Research Center General Dynamics Lockheed-Martin Hercules Aerospace Company U.S. Nitinol Owens-Corning DSB Associates...Reduction in a Plate," submitted to AIAA Journal. Paine, J. S. N., Rogers, C. A. 1993. "Characterization of Interfacial Adhesion of Nitinol Fibers

Rheology of Carbon Fibre Reinforced Cement-Based Mortar

NASA Astrophysics Data System (ADS)

Banfill, Phillip F. G.; Starrs, Gerry; McCarter, W. John

2008-07-01

Carbon fibre reinforced cement based materials (CFRCs) offer the possibility of fabricating "smart" electrically conductive materials. Rheology of the fresh mix is crucial to satisfactory moulding and fresh CFRC conforms to the Bingham model with slight structural breakdown. Both yield stress and plastic viscosity increase with increasing fibre length and volume concentration. Using a modified Viskomat NT, the concentration dependence of CFRC rheology up to 1.5% fibre volume is reported.

Nanophotonics-enabled smart windows, buildings and wearables

NASA Astrophysics Data System (ADS)

Smith, Geoff; Gentle, Angus; Arnold, Matthew; Cortie, Michael

2016-06-01

Design and production of spectrally smart windows, walls, roofs and fabrics has a long history, which includes early examples of applied nanophotonics. Evolving nanoscience has a special role to play as it provides the means to improve the functionality of these everyday materials. Improvement in the quality of human experience in any location at any time of year is the goal. Energy savings, thermal and visual comfort indoors and outdoors, visual experience, air quality and better health are all made possible by materials, whose "smartness" is aimed at designed responses to environmental energy flows. The spectral and angle of incidence responses of these nanomaterials must thus take account of the spectral and directional aspects of solar energy and of atmospheric thermal radiation plus the visible and color sensitivity of the human eye. The structures required may use resonant absorption, multilayer stacks, optical anisotropy and scattering to achieve their functionality. These structures are, in turn, constructed out of particles, columns, ultrathin layers, voids, wires, pure and doped oxides, metals, polymers or transparent conductors (TCs). The need to cater for wavelengths stretching from 0.3 to 35 μm including ultraviolet-visible, near-infrared (IR) and thermal or Planck radiation, with a spectrally and directionally complex atmosphere, and both being dynamic, means that hierarchical and graded nanostructures often feature. Nature has evolved to deal with the same energy flows, so biomimicry is sometimes a useful guide.

Smart patch integration development of compression connector structural health monitoring in overhead transmission lines

NASA Astrophysics Data System (ADS)

Wang, Hong; Wang, Jy-An J.; Ren, Fei; Chan, John

2016-04-01

Integration of smart patches into full-tension splice connectors in overhead power transmission lines was investigated. Lead zirconate titanate (PZT) -5A was used as a smart material and an aluminum beam was used as a host structure. Negative electrode termination was examined by using copper adhesive tape and direct bonding methods. Various commercial adhesives were studied for PZT integration onto the host structure. Aluminum beam specimens with integrated PZT smart patches were tested under thermal cycling at a temperature of 125°C, which is the higher-end temperature experienced by in-service aluminum conductor steel-reinforced cables. Electromechanical impedance (EMI) measurements were conducted at room temperature, and the root mean square deviation (RMSD) of the conductance signals was used to analyze the EMI data. It has been shown that the negative electrode method has an important effect on the performance of the integrated PZT. The PZT displayed more susceptibility to cracking when copper tape was used than when direct bonding was used. The reliability of PZT in direct bonding depended on the adhesives used in bonding layers. Although a hard alumina-based adhesive can lead to cracking of the PZT, a high-temperature epoxy with adequate flexibility, such as Duralco 4538D, can provide the desired performance under target thermal cycling conditions. The RMSD parameter can characterize conductance signatures effectively. It also was demonstrated that RMSD can be used to quantify the fatigue of the PZT integration system, although RMSD is used primarily as a damage index in monitoring structural health.

The Packaging Technology Study on Smart Composite Structure Based on The Embedded FBG Sensor

NASA Astrophysics Data System (ADS)

Zhang, Youhong; Chang, Xinlong; Zhang, Xiaojun; He, Xiangyong

2018-03-01

It is convenient to carry out the health monitoring of the solid rocket engine composite shell based on the embedded FBG sensor. In this paper, the packaging technology using one-way fiber layer of prepreg fiberglass/epoxy resin was proposed. The proposed packaging process is simple, and the packaged sensor structure size is flexible and convenient to use, at the mean time, the packaged structure has little effect on the pristine composite material structure.

Novel dielectric elastomer structure of soft robot

NASA Astrophysics Data System (ADS)

Li, Chi; Xie, Yuhan; Huang, Xiaoqiang; Liu, Junjie; Jin, Yongbin; Li, Tiefeng

2015-04-01

Inspired from the natural invertebrates like worms and starfish, we propose a novel elastomeric smart structure. The smart structure can function as a soft robot. The soft robot is made from a flexible elastomer as the body and driven by dielectric elastomer as the muscle. Finite element simulations based on nonlinear field theory are conducted to investigate the working condition of the structure, and guide the design of the smart structure. The effects of the prestretch, structural stiffness and voltage on the performance of the smart structure are investigated. This work can guide the design of soft robot.

Functional Polymers and Nanocomposites for 3D Printing of Smart Structures and Devices.

PubMed

Nadgorny, Milena; Ameli, Amir

2018-05-30

Three-dimensional printing (3DP) has attracted a considerable amount of attention during the past years, being globally recognized as one of the most promising and revolutionary manufacturing technologies. Although the field is rapidly evolving with significant technological advancements, materials research remains a spotlight of interest, essential for the future developments of 3DP. Smart polymers and nanocomposites, which respond to external stimuli by changing their properties and structure, represent an important group of materials that hold a great promise for the fabrication of sensors, actuators, robots, electronics, and medical devices. The interest in exploring functional materials and their 3DP is constantly growing in an attempt to meet the ever-increasing manufacturing demand of complex functional platforms in an efficient manner. In this review, we aim to outline the recent advances in the science and engineering of functional polymers and nanocomposites for 3DP technologies. The report covers temperature-responsive polymers, polymers and nanocomposites with electromagnetic, piezoresistive and piezoelectric behaviors, self-healing polymers, light- and pH-responsive materials, and mechanochromic polymers. The main objective is to link the performance and functionalities to the fundamental properties, chemistry, and physics of the materials, and to the process-driven characteristics, in an attempt to provide a multidisciplinary image and a deeper understanding of the topic. The challenges and opportunities for future research are also discussed.

Multifunctional three-dimensional macroporous nanoelectronic networks for smart materials.

PubMed

Liu, Jia; Xie, Chong; Dai, Xiaochuan; Jin, Lihua; Zhou, Wei; Lieber, Charles M

2013-04-23

Seamless and minimally invasive integration of 3D electronic circuitry within host materials could enable the development of materials systems that are self-monitoring and allow for communication with external environments. Here, we report a general strategy for preparing ordered 3D interconnected and addressable macroporous nanoelectronic networks from ordered 2D nanowire nanoelectronic precursors, which are fabricated by conventional lithography. The 3D networks have porosities larger than 99%, contain approximately hundreds of addressable nanowire devices, and have feature sizes from the 10-μm scale (for electrical and structural interconnections) to the 10-nm scale (for device elements). The macroporous nanoelectronic networks were merged with organic gels and polymers to form hybrid materials in which the basic physical and chemical properties of the host were not substantially altered, and electrical measurements further showed a >90% yield of active devices in the hybrid materials. The positions of the nanowire devices were located within 3D hybrid materials with ∼14-nm resolution through simultaneous nanowire device photocurrent/confocal microscopy imaging measurements. In addition, we explored functional properties of these hybrid materials, including (i) mapping time-dependent pH changes throughout a nanowire network/agarose gel sample during external solution pH changes, and (ii) characterizing the strain field in a hybrid nanoelectronic elastomer structures subject to uniaxial and bending forces. The seamless incorporation of active nanoelectronic networks within 3D materials reveals a powerful approach to smart materials in which the capabilities of multifunctional nanoelectronics allow for active monitoring and control of host systems.

Development of lightweight structural health monitoring systems for aerospace applications

NASA Astrophysics Data System (ADS)

Pearson, Matthew

This thesis investigates the development of structural health monitoring systems (SHM) for aerospace applications. The work focuses on each aspect of a SHM system covering novel transducer technologies and damage detection techniques to detect and locate damage in metallic and composite structures. Secondly the potential of energy harvesting and power arrangement methodologies to provide a stable power source is assessed. Finally culminating in the realisation of smart SHM structures. 1. Transducer Technology A thorough experimental study of low profile, low weight novel transducers not normally used for acoustic emission (AE) and acousto-ultrasonics (AU) damage detection was conducted. This included assessment of their performance when exposed to aircraft environments and feasibility of embedding these transducers in composites specimens in order to realise smart structures. 2. Damage Detection An extensive experimental programme into damage detection utilising AE and AU were conducted in both composites and metallic structures. These techniques were used to assess different damage mechanism within these materials. The same transducers were used for novel AE location techniques coupled with AU similarity assessment to successfully detect and locate damage in a variety of structures. 3. Energy Harvesting and Power Management Experimental investigations and numerical simulations were undertaken to assess the power generation levels of piezoelectric and thermoelectric generators for typical vibration and temperature differentials which exist in the aerospace environment. Furthermore a power management system was assessed to demonstrate the ability of the system to take the varying nature of the input power and condition it to a stable power source for a system. 4. Smart Structures The research conducted is brought together into a smart carbon fibre wing showcasing the novel embedded transducers for AE and AU damage detection and location, as well as vibration energy harvesting. A study into impact damage detection using the techniques showed the successful detection and location of damage. Also the feasibility of the embedded transducers for power generation was assessed..

Control systems using modal domain optical fiber sensors for smart structure applications

NASA Technical Reports Server (NTRS)

Lindner, Douglas K.; Reichard, Karl M.

1991-01-01

Recently, a new class of sensors has emerged for structural control which respond to environmental changes over a significant gauge length; these sensors are called distributed-effect sensors. These sensors can be fabricated with spatially varying sensitivity to the distributed measurand, and can be configured to measure a variety of structural parameters which can not be measured directly using point sensors. Examples of distributed-effect sensors include piezoelectric film, holographic sensors, and modal domain optical fiber sensors. Optical fiber sensors are particularly attractive for smart structure applications because they are flexible, have low mass, and can easily be embedded directly into materials. In this paper we describe the implementation of weighted modal domain optical fiber sensors. The mathematical model of the modal domain optical fiber sensor model is described and used to derive an expression for the sensor sensitivity. The effects of parameter variations on the sensor sensitivity are demonstrated to illustrate methods of spatially varying the sensor sensitivity.

Dynamics of Solid-Liquid Composite Beams

NASA Astrophysics Data System (ADS)

Matia, Yoav; Gat, Amir

2017-11-01

Solid-liquid composite structures received considerable attention in recent years in various fields such as smart materials, sensors, actuators and soft-robotics. We examine a beam-like appendage embedded with a set of a fluid-filled bladders, interconnected via elastic slender channels; a common arrangement in the abovementioned fields. Viscous flow within such structures is coupled with the elastic deformation of the solid. Beam deformation both creates, and is induced by, a fluidic pressure gradient and viscous flow which deforms the bladders and thus the surrounding solid. Applying concepts from poroelastic analysis, we obtain a set of three interdependent equations relating the fluidic pressure within the channel to the transverse and longitudinal displacements of the beam. Exact and approximate solutions are presented for various configurations. The results are validated and supplemented by a transient three-dimensional numerical study of the fluid-structure-interaction. The two-way coupled fluid-structure-interaction model allows the analysis and design of soft smart-metamaterials with unique mechanical properties, to applications such as touch-sensing surfaces, energy harvesting and protective gear.

Strain Sensing Based on Multiscale Composite Materials Reinforced with Graphene Nanoplatelets.

PubMed

Moriche, Rocío; Prolongo, Silvia G; Sánchez, María; Jiménez-Suárez, Alberto; Campo, Mónica; Ureña, Alejandro

2016-11-07

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are proposed to create the electrical network in this work: (a) the incorporation of the nanoplatelets into the epoxy matrix and (b) the coating of the glass fabric with a sizing filled with the same nanoplatelets. Both types of multiscale composite materials, with an in-plane electrical conductivity of ~10 -3 S/m, showed an exponential growth of the electrical resistance as the strain increases due to distancing between adjacent functionalized graphene nanoplatelets and contact loss between overlying ones. The sensitivity of the materials analyzed during this research, using the described procedures, has been shown to be higher than commercially available strain gauges. The proposed procedures for self-sensing of the structural composite material would facilitate the structural health monitoring of components in difficult to access emplacements such as offshore wind power farms. Although the sensitivity of the multiscale composite materials was considerably higher than the sensitivity of metallic foils used as strain gauges, the value reached with NH2 functionalized graphene nanoplatelets coated fabrics was nearly an order of magnitude superior. This result elucidated their potential to be used as smart fabrics to monitor human movements such as bending of fingers or knees. By using the proposed method, the smart fabric could immediately detect the bending and recover instantly. This fact permits precise monitoring of the time of bending as well as the degree of bending.

Strain characterization of embedded aerospace smart materials using shearography

NASA Astrophysics Data System (ADS)

Anisimov, Andrei G.; Müller, Bernhard; Sinke, Jos; Groves, Roger M.

2015-04-01

The development of smart materials for embedding in aerospace composites provides enhanced functionality for future aircraft structures. Critical flight conditions like icing of the leading edges can affect the aircraft functionality and controllability. Hence, anti-icing and de-icing capabilities are used. In case of leading edges made of fibre metal laminates heater elements can be embedded between composite layers. However this local heating causes strains and stresses in the structure due to the different thermal expansion coefficients of the different laminated materials. In order to characterize the structural behaviour during thermal loading full-field strain and shape measurement can be used. In this research, a shearography instrument with three spatially-distributed shearing cameras is used to measure surface displacement gradients which give a quantitative estimation of the in- and out-of-plane surface strain components. For the experimental part, two GLARE (Glass Laminate Aluminum Reinforced Epoxy) specimens with six different embedded copper heater elements were manufactured: two copper mesh shapes (straight and S-shape), three connection techniques (soldered, spot welded and overlapped) and one straight heater element with delaminations. The surface strain behaviour of the specimens due to thermal loading was measured and analysed. The comparison of the connection techniques of heater element parts showed that the overlapped connection has the smallest effect on the surface strain distribution. Furthermore, the possibility of defect detection and defect depth characterisation close to the heater elements was also investigated.

Characterization of a small Terfenol-D transducer in mechanically blocked configuration

NASA Astrophysics Data System (ADS)

Faidley, LeAnn E.; Dapino, Marcelo J.; Flatau, Alison B.

2001-08-01

In numerous applications, smart material transducers are employed to actuate upon virtually immovable structures, that is, structures whose stiffness approaches infinity in comparison with that of the transducer itself. Such mechanically blocked transducer configurations can be found in applications ranging from seismic testing and isolation of civil structures, to clamping mechanisms in linear or rotational inchworm motors. In addition to providing high blocking forces, smart materials for this type of applications must often be small in size and lightweight in order for design constraints to be met. This paper provides a characterization of the force produced by a 0.9 cm (0.35 in) diameter, 2.0 cm (0.79i in) long Terfenol-D operated under mechanically blocked conditions. Experimental results are shown for several mechanical preloads as well as various magnetic field intensities, waveforms, and frequencies. Optimal levels are deduced and discussed and the results are compared to published data for a PZT transducer of similar size operated in mechanically blocked configuration. The comparison reveals that the Terfenol-D rod provides higher blocking forces than its PZT counterpart. It is thus feasible to employ small magnetostrictive drivers in applications involving zero or near-zero displacement, particularly those based on hybrid magnetostrictive/piezoelectric designs in which high efficiencies are achieved by driving the two electrically complementary transducer materials at electrical resonance.

Space Radiation and the Challenges Towards Effective Shielding Solutions

NASA Technical Reports Server (NTRS)

Barghouty, Abdulnasser

2014-01-01

The hazards of space radiation and their effective mitigation strategies continue to pose special science and technology challenges to NASA. It is widely accepted now that shielding space vehicles and structures will have to rely on new and innovative materials since aluminum, like all high Z materials, are poor shields against the particulate and highly ionizing nature of space radiation. Shielding solutions, motivated and constrained by power and mass limitations, couple this realization with "multifunctionality," both in design concept as well as in material function and composition. Materials endowed with effective shielding properties as well as with some degree of multi-functionality may be the kernel of the so-called "radiation-smart" structures and designs. This talk will present some of the challenges and potential mitigation ideas towards the realization of such structures and designs.

Experimental Study on Stress Monitoring of Sand-Filled Steel Tube during Impact Using Piezoceramic Smart Aggregates.

PubMed

Du, Guofeng; Zhang, Juan; Zhang, Jicheng; Song, Gangbing

2017-08-22

The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structure under an impact is important for structural health monitoring. In this paper, piezoceramic Smart Aggregates (SAs) are embedded into a quartz Sand-Filled Steel Tube Column (SFSTC) to monitor the internal structural stress during impacts. The piezoceramic smart aggregates are first calibrated by an impact hammer. Tests are conducted to study the feasibility of monitoring the internal stress of a structure. The results reflect that the calibration value of the piezoceramic smart aggregate sensitivity test is in good agreement with the theoretical value, and the output voltage value of the piezoceramic smart aggregate has a good linear relationship with external forces. Impact tests are conducted on the sand-filled steel tube with embedded piezoceramic smart aggregates. By analyzing the output signal of the piezoceramic smart aggregates, the internal stress state of the structure can be obtained. Experimental results demonstrated that, under the action of impact loads, the piezoceramic smart aggregates monitor the compressive stress at different locations in the steel tube, which verifies the feasibility of using piezoceramic smart aggregate to monitor the internal stress of a structure.

Deployable Soft Composite Structures.

PubMed

Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

2016-02-19

Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel.

Deployable Soft Composite Structures

PubMed Central

Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

2016-01-01

Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel. PMID:26892762

Piezoelectric Actuator/Sensor Technology at Rockwell

NASA Technical Reports Server (NTRS)

Neurgaonkar, Ratnakar R.

1996-01-01

We describe the state-of-the art of piezoelectric materials based on perovskite and tungsten bronze families for sensor, actuator and smart structure applications. The microstructural defects in these materials have been eliminated to a large extent and the resulting materials exhibit exceedingly high performance for various applications. The performance of Rockwell actuators/sensors is at least 3 times better than commercially available products. These high performance actuators are being incorporated into various applications including, DOD, NASA and commercial. The multilayer actuator stacks fabricated from our piezoceramics are advantageous for sensing and high capacitance applications. In this presentation, we will describe the use of our high performance piezo-ceramics for actuators and sensors, including multilayer stacks and composite structures.

Workshop on Smart Structures (1st) Held at The University of Texas at Arlington on September 22-24 1993. Collection of Extended Abstracts

DTIC Science & Technology

1994-06-01

and Optimization of Composite and Sandwich Panels Using Piezoelectric Stiffeners-Actuators" Z. Chaudhry, T. Ganino and Craig A. Rogers, Virginia...Mitigation’ Abu S. Islam and Kevin C. Craig, Rensselaer Polytechnic Institute * ’Damage Detection in Composite Structures Using Piezoelectric Materials" H...Singh, L. Y. Lo and J. S. Sirkis, University of Maryland "Meaningful Damage Evolution Tracking In Composites Using Structurally Embedded Optical Fiber

Morphing wing structure with controllable twist based on adaptive bending-twist coupling

NASA Astrophysics Data System (ADS)

Raither, Wolfram; Heymanns, Matthias; Bergamini, Andrea; Ermanni, Paolo

2013-06-01

A novel semi-passive morphing airfoil concept based on variable bending-twist coupling induced by adaptive shear center location and torsional stiffness is presented. Numerical parametric studies and upscaling show that the concept relying on smart materials permits effective twist control while offering the potential of being lightweight and energy efficient. By means of an experimental characterization of an adaptive beam and a scaled adaptive wing structure, effectiveness and producibility of the structural concept are demonstrated.

Three-Dimensional Cellular Structures Enhanced By Shape Memory Alloys

NASA Technical Reports Server (NTRS)

Nathal, Michael V.; Krause, David L.; Wilmoth, Nathan G.; Bednarcyk, Brett A.; Baker, Eric H.

2014-01-01

This research effort explored lightweight structural concepts married with advanced smart materials to achieve a wide variety of benefits in airframe and engine components. Lattice block structures were cast from an aerospace structural titanium alloy Ti-6Al-4V and a NiTi shape memory alloy (SMA), and preliminary properties have been measured. A finite element-based modeling approach that can rapidly and accurately capture the deformation response of lattice architectures was developed. The Ti-6-4 and SMA material behavior was calibrated via experimental tests of ligaments machined from the lattice. Benchmark testing of complete lattice structures verified the main aspects of the model as well as demonstrated the advantages of the lattice structure. Shape memory behavior of a sample machined from a lattice block was also demonstrated.

Automated crack detection in conductive smart-concrete structures using a resistor mesh model

NASA Astrophysics Data System (ADS)

Downey, Austin; D'Alessandro, Antonella; Ubertini, Filippo; Laflamme, Simon

2018-03-01

Various nondestructive evaluation techniques are currently used to automatically detect and monitor cracks in concrete infrastructure. However, these methods often lack the scalability and cost-effectiveness over large geometries. A solution is the use of self-sensing carbon-doped cementitious materials. These self-sensing materials are capable of providing a measurable change in electrical output that can be related to their damage state. Previous work by the authors showed that a resistor mesh model could be used to track damage in structural components fabricated from electrically conductive concrete, where damage was located through the identification of high resistance value resistors in a resistor mesh model. In this work, an automated damage detection strategy that works through placing high value resistors into the previously developed resistor mesh model using a sequential Monte Carlo method is introduced. Here, high value resistors are used to mimic the internal condition of damaged cementitious specimens. The proposed automated damage detection method is experimentally validated using a 500 × 500 × 50 mm3 reinforced cement paste plate doped with multi-walled carbon nanotubes exposed to 100 identical impact tests. Results demonstrate that the proposed Monte Carlo method is capable of detecting and localizing the most prominent damage in a structure, demonstrating that automated damage detection in smart-concrete structures is a promising strategy for real-time structural health monitoring of civil infrastructure.

Reduction of Helicopter Blade-Vortex Interaction Noise by Active Rotor Control Technology

NASA Technical Reports Server (NTRS)

Yu, Yung H.; Gmelin, Bernd; Splettstoesser, Wolf; Brooks, Thomas F.; Philippe, Jean J.; Prieur, Jean

1997-01-01

Helicopter blade-vortex interaction noise is one of the most severe noise sources and is very important both in community annoyance and military detection. Research over the decades has substantially improved basic physical understanding of the mechanisms generating rotor blade-vortex interaction noise and also of controlling techniques, particularly using active rotor control technology. This paper reviews active rotor control techniques currently available for rotor blade vortex interaction noise reduction, including higher harmonic pitch control, individual blade control, and on-blade control technologies. Basic physical mechanisms of each active control technique are reviewed in terms of noise reduction mechanism and controlling aerodynamic or structural parameters of a blade. Active rotor control techniques using smart structures/materials are discussed, including distributed smart actuators to induce local torsional or flapping deformations, Published by Elsevier Science Ltd.

Elucidating Multiscale Periosteal Mechanobiology: A Key to Unlocking the Smart Properties and Regenerative Capacity of the Periosteum?

PubMed Central

Evans, Sarah F.; Chang, Hana

2013-01-01

The periosteum, a thin, fibrous tissue layer covering most bones, resides in a dynamic, mechanically loaded environment. The periosteum also provides a niche for mesenchymal stem cells. The mechanics of periosteum vary greatly between species and anatomical locations, indicating the specialized role of periosteum as bone's bounding membrane. Furthermore, periosteum exhibits stress-state-dependent mechanical and material properties, hallmarks of a smart material. This review discusses what is known about the multiscale mechanical and material properties of the periosteum as well as their potential effect on the mechanosensitive progenitor cells within the tissue. Furthermore, this review addresses open questions and barriers to understanding periosteum's multiscale structure–function relationships. Knowledge of the smart material properties of the periosteum will maximize the translation of periosteum and substitute periosteum to regenerative medicine, facilitate the development of biomimetic tissue-engineered periosteum for use in instances where the native periosteum is lacking or damaged, and provide inspiration for a new class of smart, advanced materials. PMID:23189933

Warm/cool-tone switchable thermochromic material for smart windows by orthogonally integrating properties of pillar[6]arene and ferrocene.

PubMed

Wang, Sai; Xu, Zuqiang; Wang, Tingting; Xiao, Tangxin; Hu, Xiao-Yu; Shen, Ying-Zhong; Wang, Leyong

2018-04-30

Functional materials play a vital role in the fabrication of smart windows, which can provide a more comfortable indoor environment for humans to enjoy a better lifestyle. Traditional materials for smart windows tend to possess only a single functionality with the purpose of regulating the input of solar energy. However, different color tones also have great influences on human emotions. Herein, a strategy for orthogonal integration of different properties is proposed, namely the thermo-responsiveness of ethylene glycol-modified pillar[6]arene (EGP6) and the redox-induced reversible color switching of ferrocene/ferrocenium groups are orthogonally integrated into one system. This gives rise to a material with cooperative and non-interfering dual functions, featuring both thermochromism and warm/cool tone-switchability. Consequently, the obtained bifunctional material for fabricating smart windows can not only regulate the input of solar energy but also can provide a more comfortable color tone to improve the feelings and emotions of people in indoor environments.

Realization of MEMS-IC Vertical Integration Utilizing Smart Bumpless Bonding

NASA Astrophysics Data System (ADS)

Shiozaki, Masayoshi; Moriguchi, Makoto; Sasaki, Sho; Oba, Masatoshi

This paper reports fundamental technologies, properties, and new experimental results of SBB (Smart Bumpless Bonding) to realize MEMS-IC vertical integration. Although conventional bonding technologies have had difficulties integrating MEMS and its processing circuit because of their rough bonding surfaces, fragile structures, and thermal restriction, SBB technology realized the vertical integration without thermal treatment, any adhesive materials including bumps, and chemical mechanical polishing. The SBB technology bonds sealing parts for vacuum sealing and electrodes for electrical connection simultaneously as published in previous experimental study. The plasma CVD SiO2 is utilized to realize vacuum sealing as sealing material. And Au projection studs are formed on each electrode and connected electrically between two wafers by compressive plastic deformation and surface activation. In this paper, new experimental results including vacuum sealing properties, electrical improvement, IC bonding results on the described fundamental concept and properties are reported.

Load Diffusion in Composite and Smart Structures

NASA Technical Reports Server (NTRS)

Horgan, C. O.

2003-01-01

The research carried out here builds on our previous NASA supported research on the general topic of edge effects and load diffusion in composite structures. Further fundamental solid mechanics studies were carried out to provide a basis for assessing the complicated modeling necessary for the multi-functional large scale structures used by NASA. An understanding of the fundamental mechanisms of load diffusion in composite subcomponents is essential in developing primary composite structures. Some specific problems recently considered were those of end effects in smart materials and structures, study of the stress response of pressurized linear piezoelectric cylinders for both static and steady rotating configurations, an analysis of the effect of pre-stressing and pre-polarization on the decay of end effects in piezoelectric solids and investigation of constitutive models for hardening rubber-like materials. Our goal in the study of load diffusion is the development of readily applicable results for the decay lengths in terms of non-dimensional material and geometric parameters. Analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and assessing results from finite element analyses. The decay behavior of stresses and other field quantities provides a significant aid towards this process. The analysis is also amenable to parameter study with a large parameter space and should be useful in structural tailoring studies. Special purpose analytical models of load diffusion behavior are extremely valuable in building an intuitive base for developing refined modeling strategies and in assessing results from general purpose finite element analyses. For example, a rational basis is needed in choosing where to use three-dimensional to two-dimensional transition finite elements in analyzing stiffened plates and shells. The decay behavior of stresses and other field quantities furnished by this research provides a significant aid towards this element transition issue. A priori knowledge of the extent of boundary-layers induced by edge effects is also useful in determination of the instrumentation location in structural verification tests or in material characterization tests.

Inter-crosslinking network gels having both shape memory and high ductility

NASA Astrophysics Data System (ADS)

Amano, Yoshitaka; Hidema, Ruri; Furukawa, Hidemitsu

2012-04-01

Medical treatment for injuries should be easy and quick in many accidents. Plasters or bandages are frequently used to wrap and fix injured parts. If plasters or bandages have additional smart functions, such as cooling, removability and repeatability, they will be much more useful and effective. Here we propose innovative biocompatible materials, that is, nontoxic high-strength shape-memory gels as novel smart medical materials. These smart gels were prepared from two monomers (DMAAm and SA), a polymer (HPC), and an inter-crosslinking agent (Karenz-MOI). In the synthesis of the gels, 1) a shape-memory copolymer network is made from the DMAAm and the SA, and 2) the copolymer and the HPC are crosslinked by the Karenz-MOI. Thus the crosslinking points are connected only between the different polymers. This is our original technique of developing a new network structure of gels, named Inter-Crosslinking Network (ICN). The ICN gels achieve high ductility, going up to 700% strain in tensile tests, while the ICN gels contain about 44% water. Moreover the SA has temperature dependence due to its crystallization properties; thus the ICN gels obtain shape memory properties and are named ICN-SMG. While the Young's modulus of the ICN-SMG is large below their crystallization temperature and the gels behave like plastic materials, the modulus becomes smaller above the temperature and the gels turn back to their original shape.

Calcium-energized motor protein forisome controls damage in phloem: potential applications as biomimetic "smart" material.

PubMed

Srivastava, Vineet Kumar; Tuteja, Renu; Tuteja, Narendra

2015-06-01

Forisomes are ATP independent, mechanically active proteins from the Fabaceae family (also called Leguminosae). These proteins are located in sieve tubes of phloem and function to prevent loss of nutrient-rich photoassimilates, upon mechanical injury/wounding. Forisomes are SEO (sieve element occlusion) gene family proteins that have recently been shown to be involved in wound sealing mechanism. Recent findings suggest that forisomes could act as an ideal model to study self assembly mechanism for the development of nanotechnological devices like microinstruments, the microfluidic system frequently used in space exploration missions. Technology enabling improvement in micro instruments has been identified as a key technology by NASA in future space exploration missions. Forisomes are designated as biomimetic smart materials which are calcium-energized motor proteins. Since forisomes are biomolecules from plant systems it can be doctored through genetic engineering. In contrast, "smart" materials which are not derived from plants are difficult to modify in their properties. Current levels of understanding about forisomes conformational shifts with respect to calcium ions and pH changes requires supplement of future advances with relation to its 3D structure to understand self assembly processes. In plant systems it forms blood clots in the form of occlusions to prevent nutrient fluid leakage and thus proves to be a unique damage control system of phloem tissue.

Review on pressure sensors for structural health monitoring

NASA Astrophysics Data System (ADS)

Sikarwar, Samiksha; Satyendra; Singh, Shakti; Yadav, Bal Chandra

2017-12-01

This paper reports the state of art in a variety of pressure and the detailed study of various matrix based pressure sensors. The performances of the bridges, buildings, etc. are threatened by earthquakes, material degradations, and other environmental effects. Structural health monitoring (SHM) is crucial to protect the people and also for assets planning. This study is a contribution in developing the knowledge about self-sensing smart materials and structures for the construction industry. It deals with the study of self-sensing as well as mechanical and electrical properties of different matrices based on pressure sensors. The relationships among the compression, tensile strain, and crack length with electrical resistance change are also reviewed.

Educational Pathways through Nanoscience: Nitinol as a Paradigmatic Smart Material

ERIC Educational Resources Information Center

Lisotti, Annamaria; De Renzi, Valentina; Rozzi, Carlo Andrea; Villa, Elena; Albertini, Franca; Goldoni, Guido

2013-01-01

We developed an educational path based on nitinol, a shape memory alloy which conveniently exemplifies the smart material concept, i.e., a material that performs a predetermined, reversible action in response to a change in the environment. Nitinol recovers a given shape, changes its resistivity drastically and modifies its elastic properties if…

Design, processing and characterization of mechanically alloyed galfenol & lightly rare-earth doped FeGa alloys as smart materials for actuators and transducers

NASA Astrophysics Data System (ADS)

Taheri, Parisa

Smart materials find a wide range of application areas due to their varied response to external stimuli. The different areas of application can be in our day to day life, aerospace, civil engineering applications, and mechatronics to name a few. Magnetostrictive materials are a class of smart materials that can convert energy between the magnetic and elastic states. Galfenol is a magnetostrictive alloy comprised primarily of the elements iron (Fe) and gallium (Ga). Galfenol exhibits a unique combination of mechanical and magnetostrictive (magnetic) properties that legacy smart materials do not. Galfenol's ability to function while in tension, mechanical robustness and high Curie temperature (600 °C) is attracting interest for the alloy's use in mechanically harsh and elevated temperature environments. Applications actively being investigated include transducers for down-hole use, next-generation fuel injectors, sensing, and energy harvesting devices. Understanding correlations between microstructure, electronic structure, and functional response is key to developing novel magnetostrictive materials for sensor and actuator technologies. To this end, in the first part of this thesis we report successful fabrication and investigation of magnetic and magnetostrictive properties of mechanically alloyed Fe81Ga19 compounds. For the first time, we could measure magnetostrictive properties of mechanically alloyed FeGa compounds. A maximum saturation magnetostriction of 41 ppm was achieved which is comparable to those measured from polycrystalline FeGa alloys prepared by other processing techniques, namely gas atomization and cold rolling. Overall, this study demonstrates the feasibility of large-scale production of FeGa polycrystalline alloys powders by a simple and cost-effective mechanical alloying technique. In the second part of this work, we report for the first time, experimental results pertaining to successful fabrication and advanced characterization of a series of Er/Gd-doped [110]-textured polycrystalline alloys of nominal composition, Fe83Ga17Erx (0 In the second part of this work, we report for the first time, experimental results pertaining to successful fabrication and advanced characterization of a series of Er/Gd-doped [110]-textured polycrystalline alloys of nominal composition, Fe83Ga 17Erx (0.

Smart nickel oxide materials for the applications of energy efficiency and storage

NASA Astrophysics Data System (ADS)

Lin, Feng

The present dissertation studies nickel oxide-based materials for the application of electrochromic windows and lithium-air batteries. The materials were fabricated via radio frequency magnetron sputtering and subsequently post-treated with thermal evaporation and ozone exposure. The strategies to improve electrochromic performance of nickel oxide materials were investigated including compositional control, morphology tuning, modification of electronic structure and interface engineering (i.e., Li2O 2, graphene). The electrochemical properties of the resulting materials were characterized in lithium ion electrolytes. Extremely high performing nickel oxide-based electrochromic materials were obtained in terms of optical modulation, switching kinetics, bleached-state transparency and durability, which promise the implementation of these materials for practical smart windows. With the aid of advanced synchrotron X-ray absorption spectroscopy, it is reported for the first time that the electrochromic effect in multicomponent nickel oxide-based materials arises from the reversible formation of hole states in the NiO6 cluster accompanying with the reversible formation of Li2O2. The reversible formation of Li2O 2 was successfully leveraged with the study of electro-catalysts and cathode materials for lithium-air batteries. The reversibility of Li 2O2 was thoroughly investigated using soft X-ray absorption spectroscopy and theoretical simulation, which substantiates the promise of using electrochromic films as electro-catalysts and/or cathode materials in lithium-air batteries.

Perspective and potential of smart optical materials

NASA Astrophysics Data System (ADS)

Choi, Sang H.; Duzik, Adam J.; Kim, Hyun-Jung; Park, Yeonjoon; Kim, Jaehwan; Ko, Hyun-U.; Kim, Hyun-Chan; Yun, Sungryul; Kyung, Ki-Uk

2017-09-01

The increasing requirements of hyperspectral imaging optics, electro/photo-chromic materials, negative refractive index metamaterial optics, and miniaturized optical components from micro-scale to quantum-scale optics have all contributed to new features and advancements in optics technology. Development of multifunctional capable optics has pushed the boundaries of optics into new fields that require new disciplines and materials to maximize the potential benefits. The purpose of this study is to understand and show the fundamental materials and fabrication technology for field-controlled spectrally active optics (referred to as smart optics) that are essential for future industrial, scientific, military, and space applications, such as membrane optics, filters, windows for sensors and probes, telescopes, spectroscopes, cameras, light valves, light switches, and flat-panel displays. The proposed smart optics are based on the Stark and Zeeman effects in materials tailored with quantum dot arrays and thin films made from readily polarizable materials via ferroelectricity or ferromagnetism. Bound excitonic states of organic crystals are also capable of optical adaptability, tunability, and reconfigurability. To show the benefits of smart optics, this paper reviews spectral characteristics of smart optical materials and device technology. Experiments testing the quantum-confined Stark effect, arising from rare earth element doping effects in semiconductors, and applied electric field effects on spectral and refractive index are discussed. Other bulk and dopant materials were also discovered to have the same aspect of shifts in spectrum and refractive index. Other efforts focus on materials for creating field-controlled spectrally smart active optics on a selected spectral range. Surface plasmon polariton transmission of light through apertures is also discussed, along with potential applications. New breakthroughs in micro scale multiple zone plate optics as a micro convex lens are reviewed, along with the newly discovered pseudo-focal point not predicted with conventional optics modeling. Micron-sized solid state beam scanner chips for laser waveguides are reviewed as well.

A forty-year history of fiber optic smart structures

NASA Astrophysics Data System (ADS)

Udd, Eric; Scheel, Ingrid U.

2017-04-01

In 1977 McDonnell Douglas Astronautics Company began a project on using fiber optic sensors to support the Delta Rocket program. This resulted in a series of fiber sensors to support the measurement of rotation, acoustics, vibration, strain, and temperature for a variety of applications and early work on fiber optic smart structures. The work on fiber optic smart structures transitioned in part to Blue Road Research in 1993 and continued in 2006 to the present at Columbia Gorge Research. This paper summarizes some of the efforts made by these companies to implement fiber optic smart structures over this forty year period.

The advanced magnetovision system for Smart application

NASA Astrophysics Data System (ADS)

Kaleta, Jerzy; Wiewiórski, Przemyslaw; Lewandowski, Daniel

2010-04-01

An original method, measurement devices and software tool for examination of magneto-mechanical phenomena in wide range of SMART applications is proposed. In many Hi-End market constructions it is necessary to carry out examinations of mechanical and magnetic properties simultaneously. Technological processes of fabrication of modern materials (for example cutting, premagnetisation and prestress) and advanced concept of using SMART structures involves the design of next generation system for optimization of electric and magnetic field distribution. The original fast and higher than million point static resolution scanner with mulitsensor probes has been constructed to measure full components of the magnetic field intensity vector H, and to visualize them into end user acceptable variant. The scanner has also the capability to acquire electric potentials on surface to work with magneto-piezo devices. Advanced electronic subsystems have been applied for processing of results in the Magscaner Vison System and the corresponding software - Maglab has been also evaluated. The Dipole Contour Method (DCM) is provided for modeling different states between magnetic and electric coupled materials and to visually explain the information of the experimental data. Dedicated software collaborating with industrial parametric systems CAD. Measurement technique consists of acquiring a cloud of points similarly as in tomography, 3D visualisation. The actually carried verification of abilities of 3D digitizer will enable inspection of SMART actuators with the cylindrical form, pellets with miniature sizes designed for oscillations dampers in various construction, for example in vehicle industry.

Using instability to reconfigure smart structures in a spring-mass model

NASA Astrophysics Data System (ADS)

Zhang, Jiaying; McInnes, Colin R.

2017-07-01

Multistable phenomenon have long been used in mechanism design. In this paper a subset of unstable configurations of a smart structure model will be used to develop energy-efficient schemes to reconfigure the structure. This new concept for reconfiguration uses heteroclinic connections to transition the structure between different unstable equal-energy states. In an ideal structure model zero net energy input is required for the reconfiguration, compared to transitions between stable equilibria across a potential barrier. A simple smart structure model is firstly used to identify sets of equal-energy unstable configurations using dynamical systems theory. Dissipation is then added to be more representative of a practical structure. A range of strategies are then used to reconfigure the smart structure using heteroclinic connections with different approaches to handle dissipation.

Hybrid Piezoelectric/Fiber-Optic Sensor Sheets

NASA Technical Reports Server (NTRS)

Lin, Mark; Qing, Xinlin

2004-01-01

Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

Double-beam cantilever structure with embedded intelligent damping block: Dynamics and control

NASA Astrophysics Data System (ADS)

Szmidt, Tomasz; Pisarski, Dominik; Bajer, Czesław; Dyniewicz, Bartłomiej

2017-08-01

In this paper a semi-active method to control the vibrations of twin beams connected at their tips by a smart damping element is investigated. The damping element can be made of a magnetorheological elastomer or a smart material of another type, for instance vacuum packed particles. What is crucial is the ability to modify the storage and loss moduli of the damping block by means of devices attached directly to the vibrating structure. First, a simple dynamical model of the system is proposed. The continuous model is discretized using the Galerkin procedure. Then, a practical state-feedback control law is developed. The control strategy aims at achieving the best instantaneous energy dissipation of the system. Numerical simulations confirm its effectiveness in reducing free vibrations. The proposed control strategy appears to be robust in the sense that its application does not require any knowledge of the initial conditions imposed on the structure, and its performance is better than passive solutions, especially for the system induced in the first mode.

DFT investigations on mechanical stability, electronic structure and magnetism in Co2TaZ (Z = Al, Ga, In) heusler alloys

NASA Astrophysics Data System (ADS)

Khandy, Shakeel Ahmad; Gupta, Dinesh C.

2017-12-01

Ferromagnetic Heusler compounds have vast and imminent applications for novel devices, smart materials thanks to density functional theory (DFT) based simulations, which have scored out a new approach to study these materials. We forecast the structural stability of Co2TaZ alloys on the basis of total energy calculations and mechanical stability criteria. The elastic constants, robust spin-polarized ferromagnetism and electron densities in these half-metallic alloys are also discussed. The observed structural aspects calculated to predict the stability and equilibrium lattice parameters agree well with the experimental results. The elastic parameters like elastic constants, bulk, Young’s and shear moduli, poison’s and Pugh ratios, melting temperatures, etc have been put together to establish their mechanical properties. The elaborated electronic band structures along with indirect band gaps and spin polarization favour the application of these materials in spintronics and memory device technology.

Probabilistic assessment of smart composite structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Shiao, Michael C.

1994-01-01

A composite wing with spars and bulkheads is used to demonstrate the effectiveness of probabilistic assessment of smart composite structures to control uncertainties in distortions and stresses. Results show that a smart composite wing can be controlled to minimize distortions and to have specified stress levels in the presence of defects. Structural responses such as changes in angle of attack, vertical displacements, and stress in the control and controlled plies are probabilistically assessed to quantify their respective uncertainties. Sensitivity factors are evaluated to identify those parameters that have the greatest influence on a specific structural response. Results show that smart composite structures can be configured to control both distortions and ply stresses to satisfy specified design requirements.

Characterization of a Hierarchical Network of Hyaluronic Acid/Gelatin Composite for use as a Smart Injectable Biomaterial

PubMed Central

Heris, Hossein K.; Rahmat, Meysam

2015-01-01

Hybrid HA/Ge hydrogel particles are embedded in a secondary HA network to improve their structural integrity. The internal microstructure of the particles is imaged through TEM. CSLM is used to identify the location of the Ge molecules in the microgels. Through indentation tests, the Young’s modulus of the individual particles is found to be 22 ± 2.5 kPa. The overall shear modulus of the composite is 75 ± 15 Pa at 1 Hz. The mechanical properties of the substrate are found to be viable for cell adhesion. The particles’ diameter at pH = 8 is twice that at pH = 5. The pH sensitivity is found to be appropriate for smart drug delivery. Based on their mechanical and structural properties, HA–Ge hierarchical materials may be well suited for use as injectable biomaterials for tissue reconstruction. PMID:22147507

THUNDER Piezoelectric Actuators as a Method of Stretch-Tuning an Optical Fiber Grating

NASA Technical Reports Server (NTRS)

Allison, Sidney G.; Fox, Robert L.; Froggatt, Mark E.; Childers, Brooks A.

2000-01-01

A method of stretching optical fiber holds interest for measuring strain in smart structures where the physical displacement may be used to tune optical fiber lasers. A small, light weight, low power tunable fiber laser is ideal for demodulating strain in optical fiber Bragg gratings attached to smart structures such as the re-usable launch vehicle that is being developed by NASA. A method is presented for stretching optical fibers using the THUNDER piezoelectric actuators invented at NASA Langley Research Center. THUNDER actuators use a piezoelectric layer bonded to a metal backing to enable the actuators to produce displacements larger than the unbonded piezoelectric material. The shift in reflected optical wavelength resulting from stretching the fiber Bragg grating is presented. Means of adapting THUNDER actuators for stretching optical fibers is discussed, including ferrules, ferrule clamp blocks, and plastic hinges made with stereo lithography.

Dynamic Analysis of a Two Member Manipulator Arm

NASA Technical Reports Server (NTRS)

McGinley, Mark; Shen, Ji Y.

1997-01-01

Attenuating start-up and stopping vibrations when maneuvering large payloads attached to flexible manipulator systems is a great concern for many space missions. To address this concern, it was proposed that the use of smart materials, and their applications in smart structures, may provide an effective method of control for aerospace structures. In this paper, a modified finite element model has been developed to simulate the performance of piezoelectric ceramic actuators, and was applied to a flexible two-arm manipulator system. Connected to a control voltage, the piezoelectric actuators produce control moments based on the optimal control theory. The computer simulation modeled the end-effector vibration suppression of the NASA manipulator testbed for berthing operations of the Space Shuttle to the Space Station. The results of the simulation show that the bonded piezoelectric actuators can effectively suppress follow-up vibrations of the end-effector, stimulated by some external disturbance.

Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function.

PubMed

Chang, Tianci; Cao, Xun; Li, Ning; Long, Shiwei; Gao, Xiang; Dedon, Liv R; Sun, Guangyao; Luo, Hongjie; Jin, Ping

2017-08-09

In the pursuit of energy efficient materials, vanadium dioxide (VO 2 ) based smart coatings have gained much attention in recent years. For smart window applications, VO 2 thin films should be fabricated at low temperature to reduce the cost in commercial fabrication and solve compatibility problems. Meanwhile, thermochromic performance with high luminous transmittance and solar modulation ability, as well as effective UV shielding function has become the most important developing strategy for ideal smart windows. In this work, facile Cr 2 O 3 /VO 2 bilayer coatings on quartz glasses were designed and fabricated by magnetron sputtering at low temperatures ranging from 250 to 350 °C as compared with typical high growth temperatures (>450 °C). The bottom Cr 2 O 3 layer not only provides a structural template for the growth of VO 2 (R), but also serves as an antireflection layer for improving the luminous transmittance. It was found that the deposition of Cr 2 O 3 layer resulted in a dramatic enhancement of the solar modulation ability (56.4%) and improvement of luminous transmittance (26.4%) when compared to single-layer VO 2 coating. According to optical measurements, the Cr 2 O 3 /VO 2 bilayer structure exhibits excellent optical performances with an enhanced solar modulation ability (ΔT sol = 12.2%) and a high luminous transmittance (T lum,lt = 46.0%), which makes a good balance between ΔT sol and T lum for smart windows applications. As for UV-shielding properties, more than 95.8% UV radiation (250-400 nm) can be blocked out by the Cr 2 O 3 /VO 2 structure. In addition, the visualized energy-efficient effect was modeled by heating a beaker of water using infrared imaging method with/without a Cr 2 O 3 /VO 2 coating glass.

Method for fabricating an ignitable heterogeneous stratified metal structure

DOEpatents

Barbee, T.W. Jr.; Weihs, T.

1996-08-20

A multilayer structure has a selectable: (1) propagating reaction front velocity V; (2) reaction initiation temperature attained by application of external energy; and (3) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as igniters, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t{sub i}, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D{sup n}){times}[1-(t{sub i}/D)] and n is about 0.8 to 1.2. 8 figs.

Method for fabricating an ignitable heterogeneous stratified metal structure

DOEpatents

Barbee, Jr., Troy W.; Weihs, Timothy

1996-01-01

A multilayer structure has a selectable, (i) propagating reaction front velocity V, (ii) reaction initiation temperature attained by application of external energy and (iii) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as ignitors, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t.sub.i, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D.sup.n).times.[1-(t.sub.i /D)]and n is about 0.8 to 1.2.

Material Development to Raise Awareness of Using Smart Boards: An Example Design and Development Research

ERIC Educational Resources Information Center

Günaydin, Serpil; Karamete, Aysen

2016-01-01

This study aims to develop training material that will help raise awareness in prospective teachers regarding the benefits of using smart boards in the classroom. In this study, a Type 2 design and development research method (DDR) was used. The material was developed by applying phases of ADDIE--an instructional systems design model. The…

Application of smart optical fiber sensors for structural load monitoring

NASA Astrophysics Data System (ADS)

Davies, Heddwyn; Everall, Lorna A.; Gallon, Andrew M.

2001-06-01

This paper describes a smart monitoring system, incorporating optical fiber sensing techniques, capable of providing important structural information to designers and users alike. This technology has wide industrial and commercial application in areas including aerospace, civil, maritime and automotive engineering. In order to demonstrate the capability of the sensing system it has been installed in a 35m free-standing carbon fiber yacht mast, where a complete optical network of strain and temperature sensors were embedded into a composite mast and boom during lay-up. The system was able to monitor the behavior of the composite rig through a range of handling conditions. The resulting strain information can be used by engineers to improve the structural design process. Embedded fiber optic sensors have wide ranging application for structural load monitoring. Due to their small size, optical fiber sensors can be readily embedded into composite materials. Other advantages include their immediate multiplexing capability and immunity to electro-magnetic interference. The capability of this system has been demonstrated within the maritime and industrial environment, but can be adapted for any application.

Reviews CD-ROM: Scientific American—The Amateur Scientist 3.0 Book: The New Resourceful Physics Teacher Equipment: DynaKar Book: The Fundamentals of Imaging Book: Teaching Secondary Physics Book: Novel Materials and Smart Applications Equipment: Cryptic disk Web Watch

NASA Astrophysics Data System (ADS)

2012-05-01

WE RECOMMEND Scientific American—The Amateur Scientist 3.0 Article collection spans the decades DynaKar DynaKar drives dynamics experiments The Fundamentals of Imaging Author covers whole imaging spectrum Teaching Secondary Physics Effective teaching is all in the approach Novel Materials and Smart Applications/Novel materials sample pack Resources kit samples smart materials WORTH A LOOK Cryptic disk Metal disk spins life into discussions about energy, surfaces and kinetics HANDLE WITH CARE The New Resourceful Physics Teacher Book brings creativity to physics WEB WATCH Apps for tablets and smartphones can aid physics teaching

SMART materials: Surfaces, transforms and interfaces. The commensurate engineering dimension

NASA Astrophysics Data System (ADS)

McDonach, Alaster; Gardiner, Peter T.; McEwen, Ron S.; Culshaw, Brian

1994-11-01

The future of molecularly based smart materials hinges on the development of integrated technologies addressing synthesis, assembly, shaping, etc. and some of these are now becoming clear. Even in the bolt on era new technologies will allow issues of commensurate engineering to be addressed.

Development of 2D and 3D structured textile batteries processing conductive material with Tailored Fiber Placement (TFP)

NASA Astrophysics Data System (ADS)

Normann, M.; Grethe, T.; Zöll, K.; Ehrmann, A.; Schwarz-Pfeiffer, A.

2017-10-01

In recent years smart textiles have gained a significant increase of attention. Electrotherapeutic socks, light emitting dresses or shirts with integrated sensors, having the ability to process data of vital parameters, are just a few examples and the full potential is not yet exhausted: Smart textiles are not only used for clothing purposes. Sensors for the care of the elderly, light applications for home textiles and monitoring systems in the automotive section are promising fields for the future. For all these electrical and electronic features, the supply of power is needed. The most common used power supplies, however, are not flexible, often not lightweight and therefore a huge problem for the integration into textile products. In recent projects, textile-based batteries are being developed. Metal-coated fabrics and yarns (e.g. silver, copper, nickel, zinc) as well as carbon based materials were used to create textile based energy sources. This article gives an overview of textile based electrochemical cells by combining different conductive yarns and a gel-electrolyte. The available materials will be processed by embroidering utilizing tailored fiber placement (TFP). The electrical characteristics of different embroidered patterns and material combinations are examined.

Development of smart textiles with embedded fiber optic chemical sensors

NASA Astrophysics Data System (ADS)

Khalil, Saif E.; Yuan, Jianming; El-Sherif, Mahmoud A.

2004-03-01

Smart textiles are defined as textiles capable of monitoring their own health conditions or structural behavior, as well as sensing external environmental conditions. Smart textiles appear to be a future focus of the textile industry. As technology accelerates, textiles are found to be more useful and practical for potential advanced technologies. The majority of textiles are used in the clothing industry, which set up the idea of inventing smart clothes for various applications. Examples of such applications are medical trauma assessment and medical patients monitoring (heart and respiration rates), and environmental monitoring for public safety officials. Fiber optics have played a major role in the development of smart textiles as they have in smart structures in general. Optical fiber integration into textile structures (knitted, woven, and non-woven) is presented, and defines the proper methodology for the manufacturing of smart textiles. Samples of fabrics with integrated optical fibers were processed and tested for optical signal transmission. This was done in order to investigate the effect of textile production procedures on optical fiber performance. The tests proved the effectiveness of the developed methodology for integration of optical fibers without changing their optical performance or structural integrity.

Multifunctional Energy Storage and Conversion Devices.

PubMed

Huang, Yan; Zhu, Minshen; Huang, Yang; Pei, Zengxia; Li, Hongfei; Wang, Zifeng; Xue, Qi; Zhi, Chunyi

2016-10-01

Multifunctional energy storage and conversion devices that incorporate novel features and functions in intelligent and interactive modes, represent a radical advance in consumer products, such as wearable electronics, healthcare devices, artificial intelligence, electric vehicles, smart household, and space satellites, etc. Here, smart energy devices are defined to be energy devices that are responsive to changes in configurational integrity, voltage, mechanical deformation, light, and temperature, called self-healability, electrochromism, shape memory, photodetection, and thermal responsivity. Advisable materials, device designs, and performances are crucial for the development of energy electronics endowed with these smart functions. Integrating these smart functions in energy storage and conversion devices gives rise to great challenges from the viewpoint of both understanding the fundamental mechanisms and practical implementation. Current state-of-art examples of these smart multifunctional energy devices, pertinent to materials, fabrication strategies, and performances, are highlighted. In addition, current challenges and potential solutions from materials synthesis to device performances are discussed. Finally, some important directions in this fast developing field are considered to further expand their application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Doing Your Part To Help Your Child Become SMART (Successful, Motivated, Autonomous, Responsible, Thoughtful): Six Workshops on Parenting SMART Learners.

ERIC Educational Resources Information Center

Sattes, Beth; Walsh, Jackie; Hickman, Mickey

A SMART Learner is a lifelong learner who can adapt to rapid change and who possesses characteristics associated with success in and out of school. These workshop materials to help parents help their children become SMART learners provide: information from current research and best practice; learning activities that will actively engage parents in…

Engineering artificial machines from designable DNA materials for biomedical applications.

PubMed

Qi, Hao; Huang, Guoyou; Han, Yulong; Zhang, Xiaohui; Li, Yuhui; Pingguan-Murphy, Belinda; Lu, Tian Jian; Xu, Feng; Wang, Lin

2015-06-01

Deoxyribonucleic acid (DNA) emerges as building bricks for the fabrication of nanostructure with complete artificial architecture and geometry. The amazing ability of DNA in building two- and three-dimensional structures raises the possibility of developing smart nanomachines with versatile controllability for various applications. Here, we overviewed the recent progresses in engineering DNA machines for specific bioengineering and biomedical applications.

Engineering Artificial Machines from Designable DNA Materials for Biomedical Applications

PubMed Central

Huang, Guoyou; Han, Yulong; Zhang, Xiaohui; Li, Yuhui; Pingguan-Murphy, Belinda; Lu, Tian Jian; Xu, Feng

2015-01-01

Deoxyribonucleic acid (DNA) emerges as building bricks for the fabrication of nanostructure with complete artificial architecture and geometry. The amazing ability of DNA in building two- and three-dimensional structures raises the possibility of developing smart nanomachines with versatile controllability for various applications. Here, we overviewed the recent progresses in engineering DNA machines for specific bioengineering and biomedical applications. PMID:25547514

A Temperature‐Responsive Smart Europium Metal‐Organic Framework Switch for Reversible Capture and Release of Intrinsic Eu3+ Ions

PubMed Central

Zhu, Min; Song, Xue‐Zhi; Zhao, Shu‐Na; Meng, Xing; Wu, Lan‐Lan; Wang, Cheng

2015-01-01

Stimuli‐responsive structural transformations are emerging as a scaffold to develop a charming class of smart materials. A EuL metal‐organic framework (MOF) undergoes a reversible temperature‐stimulated single‐crystal to single‐crystal transformation, showing a specific behavior of fast capture/release of free Eu3+ in the channels at low and room temperatures. At room temperature, compound 1a is obtained with one free carboxylate group severing as further hook, featuring one‐dimensional square channels filled with intrinsic free europium ions. Trigged by lowering the ambient temperature, 1b is gained. In 1b, the intrinsic free europium ions can be fast captured by the carboxylate‐hooks anchored in the framework, resulting in the structural change and its channel distortion. To the best of our knowledge, this is the first report of such a rapid and reversible switch stemming from dynamic control between noncovalent and covalent Eu–ligand interactions. Utilizing EuL MOF to detect highly explosive 2,4,6‐trinitrophenol at room temperature and low temperature provides a glimpse into the potential of this material in fluorescence sensors. PMID:27980931

NASA's Aeronautics Vision

NASA Technical Reports Server (NTRS)

Tenney, Darrel R.

2004-01-01

Six long-term technology focus areas are: 1. Environmentally Friendly, Clean Burning Engines. Focus: Develop innovative technologies to enable intelligent turbine engines that significantly reduce harmful emissions while maintaining high performance and increasing reliability. 2. New Aircraft Energy Sources and Management. Focus: Discover new energy sources and intelligent management techniques directed towards zero emissions and enable new vehicle concepts for public mobility and new science missions. 3. Quiet Aircraft for Community Friendly Service. Focus: Develop and integrate noise reduction technology to enable unrestricted air transportation service to all communities. 4. Aerodynamic Performance for Fuel Efficiency. Focus: Improve aerodynamic efficiency,structures and materials technologies, and design tools and methodologies to reduce fuel burn and minimize environmental impact and enable new vehicle concepts and capabilities for public mobility and new science missions. 5. Aircraft Weight Reduction and Community Access. Focus: Develop ultralight smart materials and structures, aerodynamic concepts, and lightweight subsystems to increase vehicle efficiency, leading to high altitude long endurance vehicles, planetary aircraft, advanced vertical and short takeoff and landing vehicles and beyond. 6. Smart Aircraft and Autonomous Control. Focus: Enable aircraft to fly with reduced or no human intervention, to optimize flight over multiple regimes, and to provide maintenance on demand towards the goal of a feeling, seeing, sensing, sentient air vehicle.

Admixtures in Cement-Matrix Composites for Mechanical Reinforcement, Sustainability, and Smart Features

PubMed Central

Bastos, Guillermo; Patiño-Barbeito, Faustino; Patiño-Cambeiro, Faustino; Armesto, Julia

2016-01-01

For more than a century, several inclusions have been mixed with Portland cement—nowadays the most-consumed construction material worldwide—to improve both the strength and durability required for construction. The present paper describes the different families of inclusions that can be combined with cement matrix and reviews the achievements reported to date regarding mechanical performance, as well as two other innovative functionalities of growing importance: reducing the high carbon footprint of Portland cement, and obtaining new smart features. Nanomaterials stand out in the production of such advanced features, allowing the construction of smart or multi-functional structures by means of thermal- and strain-sensing, and photocatalytic properties. The first self-cleaning concretes (photocatalytic) have reached the markets. In this sense, it is expected that smart concretes will be commercialized to address specialized needs in construction and architecture. Conversely, other inclusions that enhance strength or reduce the environmental impact remain in the research stage, in spite of the promising results reported in these issues. Despite the fact that such functionalities are especially profitable in the case of massive cement consumption, the shift from the deeply established Portland cement to green cements still has to overcome economic, institutional, and technical barriers. PMID:28774091

Smart Polyacrylonitrile (PAN) Nanofibers with Thermal Energy Storage and Retrieval Functionality

NASA Astrophysics Data System (ADS)

Cherry, De'Andre James

Phase change materials (PCMs) are generally substances with a high heat of fusion in the process of solid to liquid phase change. The nature of PCMs make them efficient materials to store and retrieve large amounts of thermal energy. Presently, high efficiency thermal energy storage/retrieval in applications where flexibility and space saving are required, such as smart textiles, still remains as a challenge. In this study, lauric acid (LA) and myristic acid (MA) were combined to prepare a specific binary fatty acid eutectic (LA-MA) with a melting point near the operating body temperature of a human being and then encapsulated in polyacrylonitrile (PAN) nanofibers through the electrospinning technique. Functionalized PCM-enhanced PAN nanofibers containing LA-MA at 30%, 50%, 70% and 100% of the weight of the PAN were successfully synthesized. The morphological structures and thermal energy storage capacity of the PCM-enhanced PAN nanofibers were characterized by electron microscopy (EM) and differential scanning calorimetry (DSC). The novel PCM-enhanced PAN nanofibers maintained their cylindrical fiber morphology after multiple heating-cooling cycles and retained their latent heat storage functionality. Thus, it is envisioned that the prepared PCM-enhanced PAN nanofibers will find use in applications such as smart textiles where temperature regulation functionality is required.

Semi Active Control of Civil Structures, Analytical and Numerical Studies

NASA Astrophysics Data System (ADS)

Kerboua, M.; Benguediab, M.; Megnounif, A.; Benrahou, K. H.; Kaoulala, F.

Structural control for civil structures was born out of a need to provide safer and more efficient designs with the reality of limited resources. The purpose of structural control is to absorb and to reflect the energy introduced by dynamic loads such as winds, waves, earthquakes, and traffic. Today, the protection of civil structures from severe dynamic loading is typically achieved by allowing the structures to be damaged. Semi-active control devices, also called "smart" control devices, assume the positive aspects of both the passive and active control devices. A semi-active control strategy is similar to the active control strategy. Only here, the control actuator does not directly apply force to the structure, but instead it is used to control the properties of a passive energy device, a controllable passive damper. Semi-active control strategies can be used in many of the same civil applications as passive and active control. One method of operating smart cable dampers is in a purely passive capacity, supplying the dampers with constant optimal voltage. The advantages to this strategy are the relative simplicity of implementing the control strategy as compared to a smart or active control strategy and that the dampers are more easily optimally tuned in- place, eliminating the need to have passive dampers with unique optimal damping coefficients. This research investigated semi-active control of civil structures for natural hazard mitigation. The research has two components, the seismic protection of buildings and the mitigation of wind-induced vibration in structures. An ideal semi-active motion equation of a composite beam that consists of a cantilever beam bonded with a PZT patch using Hamilton's principle and Galerkin's method was treated. A series R-L and a parallel R-L shunt circuits are coupled into the motion equation respectively by means of the constitutive relation of piezoelectric material and Kirchhoff's law to control the beam vibration. A numerical example of the parallel R-L piezoelectric vibration shunt control simulated with MATLAB® is presented. An analytical study of the resistor-inductor (R-L) passive piezoelectric vibration shunt control of a cantilever beam was undertaken. The modal and strain analyses were performed by varying the material properties and geometric configurations of the piezoelectric transducer in relation to the structure in order to maximize the mechanical strain produced in the piezoelectric transducer.

Overview of the DARPA/AFRL/NASA Smart Wing Phase II program

NASA Astrophysics Data System (ADS)

Kudva, Jayanth N.; Sanders, Brian P.; Pinkerton-Florance, Jennifer L.; Garcia, Ephrahim

2001-06-01

The DARPA/AFRL/NASA Smart Wing program, conducted by a team led by Northrop Grumman Corporation (NGC) under the DARPA Smart Materials and Structures initiative, addresses the development of smart technologies and demonstration of relevant concepts to improve the aerodynamic performance of military aircraft. This paper presents an overview of the smart wing program. The program is divided into two phases. Under Phase 1, (1995 - 1999) the NGC team developed adaptive wing structures with integrated actuation mechanisms to replace standard hinged control surfaces and provide variable, optimal aerodynamic shapes for a variety of flight regimes. Two half-span 16% scale wind tunnel models, representative of an advanced military aircraft wing, one with conventional control surfaces and the other with shape memory alloy (SMA) actuated smart control surfaces, were fabricated and tested in the NASA Langley Research Center (LaRC) Transonic Dynamics Tunnel (TDT) wind tunnel during two series of tests, conducted in May 1996 and June 1998, respectively. Details of the Phase 1 effort are documented in several papers. The on-going Phase 2 effort discussed here was started in January 1997 and includes several significant improvements over Phase 1: 1) a much larger, full-span model; 2) both leading edge (LE) and trailing edge (TE) smart control surfaces; 3) high-band width actuation systems; and 4) wind tunnel tests at transonic Mach numbers and high dynamic pressures (up to 300 psf.) representative of operational flight regimes. Phase 2 includes two wind tunnel tests, both at the NASA LaRC TDT - the first one was completed in March 2000 and the second (and final) test is scheduled for April 2001. The first test-demonstrated roll-effectiveness over a wide range of Mach numbers achieved using a combination of hingeless, smoothly contoured, SMA actuated, LE and TE control surfaces. The second test addresses the development and demonstration of high bandwidth actuation. An overview of the Phase 2 effort is presented here; detailed discussions of the wind tunnel testing, model design and fabrication, and actuation system development are given in companion papers.

Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications

NASA Astrophysics Data System (ADS)

Wei, Yang; Torah, Russel; Yang, Kai; Beeby, Steve; Tudor, John

2013-07-01

Free-standing cantilevers have been fabricated by screen printing sacrificial and structural layers onto a standard polyester cotton fabric. By printing additional conductive layers, a complete capacitive motion sensor on fabric using only screen printing has been fabricated. This type of free-standing structure cannot currently be fabricated using conventional fabric manufacturing processes. In addition, compared to conventional smart fabric fabrication processes (e.g. weaving and knitting), screen printing offers the advantages of geometric design flexibility and the ability to simultaneously print multiple devices of the same or different designs. Furthermore, a range of active inks exists from the printed electronics industry which can potentially be applied to create many types of smart fabric. Four cantilevers with different lengths have been printed on fabric using a five-layer structure with a sacrificial material underneath the cantilever. The sacrificial layer is subsequently removed at 160 °C for 30 min to achieve a freestanding cantilever above the fabric. Two silver electrodes, one on top of the cantilever and the other on top of the fabric, are used to capacitively detect the movement of the cantilever. In this way, an entirely printed motion sensor is produced on a standard fabric. The motion sensor was initially tested on an electromechanical shaker rig at a low frequency range to examine the linearity and the sensitivity of each design. Then, these sensors were individually attached to a moving human forearm to evaluate more representative results. A commercial accelerometer (Microstrain G-link) was mounted alongside for comparison. The printed sensors have a similar motion response to the commercial accelerometer, demonstrating the potential of a printed smart fabric motion sensor for use in intelligent clothing applications.

Materials Discovery via CALYPSO Methodology

NASA Astrophysics Data System (ADS)

Ma, Yanming

2014-03-01

Materials design has been the subject of topical interests in materials and physical sciences for long. Atomistic structures of materials occupy a central and often critical role, when establishing a correspondence between materials performance and their basic compositions. Theoretical prediction of atomistic structures of materials with the only given information of chemical compositions becomes crucially important, but it is extremely difficult as it basically involves in classifying a huge number of energy minima on the lattice energy surface. To tackle the problems, we have developed an efficient CALYPSO (Crystal structural AnLYsis by Particle Swarm Optimization) approach for structure prediction from scratch based on particle swarm optimization algorithm by taking the advantage of swarm intelligence and the spirit of structures smart learning. The method has been coded into CALYPSO software (http://www.calypso.cn) which is free for academic use. Currently, CALYPSO method is able to predict structures of three-dimensional crystals, isolated clusters or molecules, surface reconstructions, and two-dimensional layers. The applications of CALYPSO into purposed materials design of layered materials, high-pressure superconductors, and superhard materials were successfully made. Our design of superhard materials introduced a useful scheme, where the hardness value has been employed as the fitness function. This strategy might also be applicable into design of materials with other desired functional properties (e.g., thermoelectric figure of merit, topological Z2 number, etc.). For such a structural design, a well-understood structure to property formulation is required, by which functional properties of materials can be easily acquired at given structures. An emergent application is seen on design of photocatalyst materials.

Easy methods to study the smart energetic TNT/CL-20 co-crystal.

PubMed

Li, Huarong; Shu, Yuanjie; Gao, Shijie; Chen, Ling; Ma, Qing; Ju, Xuehai

2013-11-01

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a high-energy nitramine explosive with high mechanical sensitivity. 2,4,6-trinitrotoluene (TNT) is insensitive but by no means a high performance explosive. To reveal the significant importance and smart-material functionality of the energetic-energetic co-crystals, the stability, mechanical and explosive properties TNT/CL-20 co-crystal, TNT crystal and CL-20 crystal were studied. Non-hydrogen bonded non-covalent interactions govern the structures of energetic-energetic co-crystals. However, it is very difficult to accurately calculate the non-covalent intermolecular interaction energies. In this paper, the local conformation and the intricate non-covalent interactions were effectively mapped and analyzed from the electron density (ρ) and its derivatives. The results show that the two components TNT and CL-20 are connected mainly by nitro-aromatic interactions, and nitro-nitro interactions. The steric interactions in TNT/CL-20 could not be confronted with the attractive interactions. Moreover, the scatter graph of TNT crystal reveals the reason why TNT is brittle. The detailed electrostatic potential analysis predicted that the detonation velocities (D) and impact sensitivity for the compounds both increase in the sequence of CL-20 > TNT/CL-20 co-crystal > TNT. Additionally, TNT/CL-20 co-crystal has better malleability than its pure components. This demonstrates the capacity and the feasibility of realizing explosive smart materials by co-crystallization, even if strong hydrogen bonding schemes are generally lacking in energetic materials.

Porous Shape Memory Polymers

PubMed Central

Hearon, Keith; Singhal, Pooja; Horn, John; Small, Ward; Olsovsky, Cory; Maitland, Kristen C.; Wilson, Thomas S.; Maitland, Duncan J.

2013-01-01

Porous shape memory polymers (SMPs) include foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. Porous SMPs exhibit active structural and volumetric transformations and have driven investigations in fields ranging from biomedical engineering to aerospace engineering to the clothing industry. The present review article examines recent developments in porous SMPs, with focus given to structural and chemical classification, methods of characterization, and applications. We conclude that the current body of literature presents porous SMPs as highly interesting smart materials with potential for industrial use. PMID:23646038

Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

PubMed

Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

2016-07-01

Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent Results from NASA's Morphing Project

NASA Technical Reports Server (NTRS)

McGowan, Anna-Maria R.; Washburn, Anthony E.; Horta, Lucas G.; Bryant, Robert G.; Cox, David E.; Siochi, Emilie J.; Padula, Sharon L.; Holloway, Nancy M.

2002-01-01

The NASA Morphing Project seeks to develop and assess advanced technologies and integrated component concepts to enable efficient, multi-point adaptability in air and space vehicles. In the context of the project, the word "morphing" is defined as "efficient, multi-point adaptability" and may include macro, micro, structural and/or fluidic approaches. The project includes research on smart materials, adaptive structures, micro flow control, biomimetic concepts, optimization and controls. This paper presents an updated overview of the content of the Morphing Project including highlights of recent research results.

Microstructure and calorimetric behavior of laser welded open cell foams in CuZnAl shape memory alloy

NASA Astrophysics Data System (ADS)

Biffi, Carlo Alberto; Previtali, Barbara; Tuissi, Ausonio

Cellular shape memory alloys (SMAs) are very promising smart materials able to combine functional properties of the material with lightness, stiffness, and damping capacity of the cellular structure. Their processing with low modification of the material properties remains an open question. In this work, the laser weldability of CuZnAl SMA in the form of open cell foams was studied. The cellular structure was proved to be successfully welded in lap joint configuration by using a thin plate of the same alloy. Softening was seen in the welded bead in all the investigated ranges of process speed as well as a double stage heat affected zone was identified due to different microstructures; the martensitic transformation was shifted to higher temperatures and the corresponding peaks were sharper with respect to the base material due to the rapid solidification of the material. Anyways, no compositional variations were detected in the joints.

Decentralized adaptive control designs and microstrip antennas for smart structures

NASA Astrophysics Data System (ADS)

Khorrami, Farshad; Jain, Sandeep; Das, Nirod K.

1996-05-01

Smart structures lend themselves naturally to a decentralized control design framework, especially with adaptation mechanisms. The main reason being that it is highly undesirable to connect all the sensors and actuators in a large structure to a central processor. It is rather desirable to have local decision-making at each smart patch. Furthermore, this local controllers should be easily `expandable' to `contractible.' This corresponds to the fact that addition/deletion of several smart patches should not require a total redesign of the control system. The decentralized control strategies advocated in this paper are of expandable/contractible type. On another front, we are considering utilization of micro-strip antennas for power transfer to and from smart structures. We have made preliminary contributions in this direction and further developments are underway. These approaches are being pursued for active vibration damping and noise cancellation via piezoelectric ceramics although the methodology is general enough to be applicable to other type of active structures.

Scale-up of nature’s tissue weaving algorithms to engineer advanced functional materials

NASA Astrophysics Data System (ADS)

Ng, Joanna L.; Knothe, Lillian E.; Whan, Renee M.; Knothe, Ulf; Tate, Melissa L. Knothe

2017-01-01

We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently “smart” material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues’ biological, mechanical and organizational detail to create advanced functional materials. Here, a novel approach is established to scale up the multidimensional fiber patterns of natural soft tissue weaves for rapid prototyping of advanced functional materials. First second harmonic generation and two-photon excitation microscopy is used to map the microscopic three-dimensional (3D) alignment, composition and distribution of the collagen and elastin fibers of periosteum, the soft tissue sheath bounding all nonarticular bone surfaces in our bodies. Then, using engineering rendering software to scale up this natural tissue fabric, as well as multidimensional weaving algorithms, macroscopic tissue prototypes are created using a computer-controlled jacquard loom. The capacity to prototype scaled up architectures of natural fabrics provides a new avenue to create advanced functional materials.

Nanofibrous Smart Fabrics from Twisted Yarns of Electrospun Piezopolymer.

PubMed

Yang, Enlong; Xu, Zhe; Chur, Lucas K; Behroozfar, Ali; Baniasadi, Mahmoud; Moreno, Salvador; Huang, Jiacheng; Gilligan, Jules; Minary-Jolandan, Majid

2017-07-19

Smart textiles are envisioned to make a paradigm shift in wearable technologies to directly impart functionality into the fibers rather than integrating sensors and electronics onto conformal substrates or skin in wearable devices. Among smart materials, piezoelectric fabrics have not been widely reported, yet. Piezoelectric smart fabrics can be used for mechanical energy harvesting, for thermal energy harvesting through the pyroelectric effect, for ferroelectric applications, as pressure and force sensors, for motion detection, and for ultrasonic sensing. We report on mechanical and material properties of the plied nanofibrous piezoelectric yarns as a function of postprocessing conditions including thermal annealing and drawing (stretching). In addition, we used a continuous electrospinning setup to directly produce P(VDF-TrFE) nanofibers and convert them into twisted plied yarns, and demonstrated application of these plied yarns in woven piezoelectric fabrics. The results of this work can be an early step toward realization of piezoelectric smart fabrics.

SMART Boards Rock

ERIC Educational Resources Information Center

Giles, Rebecca M.; Shaw, Edward L.

2011-01-01

SMART Board is a technology that combines the functionality of a whiteboard, computer, and projector into a single system. The interactive nature of the SMART Board offers many practical uses for providing an introduction to or review of material, while the large work area invites collaboration through social interaction and communication. As a…

Electrochromic NiO thin films prepared by spin coating

NASA Astrophysics Data System (ADS)

Özütok, F.; Demiri, S.; Özbek, E.

2017-02-01

Recently, smart windows are very important because they are often being used in smart buildings and car glasses (windows). At this point, producing effective electrochromic materials is so necessary. In this study, we produced NiO thin films by using spin coating technique on In-doped SnO2 (ITO) substrate. Nickel proportions of these nickel oxide (NiO) films are 3, 5 and 7 %. Nickel acetate tetrahydrate is the initial solution and solvents are ethylene gl ycol and n-hexzane. Structural properties and surface images are investigated by using x-ray diffactometer (XRD) and scanning electron microscope (SEM) device, respectively. In addition, electrochemical behavior is investigated by cyclic voltammetry. A correlation between surface morphology and electrochromic performance was observed as well.

Risk Identification in a Smart Monitoring System Used to Preserve Artefacts Based on Textile Materials

NASA Astrophysics Data System (ADS)

Diaconescu, V. D.; Scripcariu, L.; Mătăsaru, P. D.; Diaconescu, M. R.; Ignat, C. A.

2018-06-01

Exhibited textile-materials-based artefacts can be affected by the environmental conditions. A smart monitoring system that commands an adaptive automatic environment control system is proposed for indoor exhibition spaces containing various textile artefacts. All exhibited objects are monitored by many multi-sensor nodes containing temperature, relative humidity and light sensors. Data collected periodically from the entire sensor network is stored in a database and statistically processed in order to identify and classify the environment risk. Risk consequences are analyzed depending on the risk class and the smart system commands different control measures in order to stabilize the indoor environment conditions to the recommended values and prevent material degradation.

Preface

NASA Astrophysics Data System (ADS)

Lexcellent, C.; Patoor, E.

2004-06-01

This international conference was held between the 18 and the 23th may 2003, in the "Villa Clythia" belonging to the CAES of the french "Comité National de la Recherche Scientifique CNRS" at Fréjus (France). The scope of this EMMC7 conference was about the use of smart materials which permits the conception of some adaptive systems for industrial applications. A special attention was devoted to active and passive controls of damping in structures. The use of this new class of materials (shape memory alloys, piezoelectric ceramics, TRIP steels, ferromagnetic shape memory alloys, ...) implies the development of numerical tools for computer assisted design process. Complexity of the involved material behaviour requires a deep understanding of strain mechanisms (martensitic phase transformation, reorientation process of domains), the use of accurate experimental techniques and advanced modelling approaches at various scale (micro, meso, macroscopic). In this purpose, it is necessary to use some coupled calculations connecting different fields of physics such as thermal, electromagnetism, electricity and mechanics of materials ones. The conference topic gave the opportunity of fruitful discussions between the mechanics of materials communauty and the specialists of damping or passive control. The scientific program contains nine oral sessions and one poster session. - Experimental characterization of the shape memory alloys thermomechanical behavior (two sessions) - Modeling of the shape memory alloy thermomechanical behavior (two sessions) - Ferromagnetic shape memory alloys behavior (one session) - Piezoelectric ceramics behavior (one session) - Transformation induced plasticity steel behavior (one session) - Hybrid structures including smart materials as sensor or actuator (one session) - Adaptive structure for vibration control (one session) - Poster session. The conference programm contains 50 lectures. 57 scientists were present and come from 14 different countries: 20 from France, 7 from Germany, 6 from Italy, 4 from Russia, 4 from Finland and 5 from USA ... This scientific programm allows all the participants interesting exchanges on "the state of art" about smart materials and adaptive systems. In the aim of its publication in the Proceedings of the EMMC7 Conference (EDP Sciences "Journal de Physique IV") each paper was expertised by two reviewers belonging to the International Scientific Committee and also other specialists. On that occasion, we will thank them for their very important contribution of the scientific level quality of the Proceedings. We will also thank: the sponsors of the Conference: Délégation Générale aux Armements (DGA), le Ministère de la Recherche, l'Université de Metz, l'ENSAM, le CNRS, l'Association Française de Mécanique et l'Institut des Microtechniques de Franche-Comté, the members of the organizing committee, the MECAMAT committee for trusting us, EDP Sciences for the Proceedings, The "Villa Clythia" team for his nice help in the material organization, ... and all the participants. The Co-chairmen Christian LEXCELLENT et Étienne PATOOR

Conjoint Forming - Technologies for Simultaneous Forming and Joining

NASA Astrophysics Data System (ADS)

Groche, P.; Wohletz, S.; Mann, A.; Krech, M.; Monnerjahn, V.

2016-03-01

The market demand for new products optimized for e. g. lightweight applications or smart components leads to new challenges in production engineering. Hybrid structures represent one promising approach. They aim at higher product performance by using a suitable combination of different materials. The developments of hybrid structures stimulate the research on joining of dissimilar materials. Since they allow for joining dissimilar materials without external heating technologies based on joining by plastic deformation seem to be of special attractiveness. The paper at hand discusses the conjoint forming approach. This approach combines forming and joining in one process. Two or more workpieces are joined while at least one workpiece is plastically deformed. After presenting the fundamental joining mechanisms, the conjoint forming approach is discussed comprehensively. Examples of conjoint processes demonstrate the effectiveness and reveal the underlying phenomena.

'NASA Invention of the Year' Controls Noise and Vibration

NASA Technical Reports Server (NTRS)

2007-01-01

Developed at NASA's Langley Research Center, the Macro-Fiber Composite (MFC) is designed to control vibration, noise, and deflections in composite structural beams and panels. Smart Material Corporation specializes in the development of piezocomposite components, and licensed the MFC technology from Langley in 2002. To date, Smart Material Corporation has sold MFCs to over 120 customers, including such industry giants as Volkswagen, Toyota, Honda, BMW, General Electric, and the tennis company, HEAD. The company estimates that its customers have filed at least 100 patents for their various unique uses of the technology. In addition, the company's product portfolio has grown to include piezoceramic fibers and fiber composites, piezoceramic actuators and sensors, and test equipment for these products. It also offers a compact, lightweight power system for MFC testing and validation. Consumer applications already on the market include piezoelectric systems as part of audio speakers, phonograph cartridges and microphones, and recreational products requiring vibration control, such as skis, snowboards, baseball bats, hockey sticks, and tennis racquets.

Functionalized Nanocellulose-Integrated Heterolayered Nanomats toward Smart Battery Separators.

PubMed

Kim, Jung-Hwan; Gu, Minsu; Lee, Do Hyun; Kim, Jeong-Hoon; Oh, Yeon-Su; Min, Sa Hoon; Kim, Byeong-Su; Lee, Sang-Young

2016-09-14

Alternative materials obtained from natural resources have recently garnered considerable attention as an innovative solution to bring unprecedented advances in various energy storage systems. Here, we present a new class of heterolayered nanomat-based hierarchical/asymmetric porous membrane with synergistically coupled chemical activity as a nanocellulose-mediated green material strategy to develop smart battery separator membranes far beyond their current state-of-the-art counterparts. This membrane consists of a terpyridine (TPY)-functionalized cellulose nanofibril (CNF) nanoporous thin mat as the top layer and an electrospun polyvinylpyrrolidone (PVP)/polyacrylonitrile (PAN) macroporous thick mat as the support layer. The hierarchical/asymmetric porous structure of the heterolayered nanomat is rationally designed with consideration of the trade-off between leakage current and ion transport rate. The TPY (to chelate Mn(2+) ions) and PVP (to capture hydrofluoric acid)-mediated chemical functionalities bring a synergistic coupling in suppressing Mn(2+)-induced adverse effects, eventually enabling a substantial improvement in the high-temperature cycling performance of cells.

Force Project Technology Presentation to the NRCC

DTIC Science & Technology

2014-02-04

Functional Bridge components Smart Odometer Adv Pretreatment Smart Bridge Multi-functional Gap Crossing Fuel Automated Tracking System Adv...comprehensive matrix of candidate composite material systems and textile reinforcement architectures via modeling/analyses and testing. Product(s...Validated Dynamic Modeling tool based on parametric study using material models to reliably predict the textile mechanics of the hose

Smart Electronic Textiles.

PubMed

Weng, Wei; Chen, Peining; He, Sisi; Sun, Xuemei; Peng, Huisheng

2016-05-17

This Review describes the state-of-the-art of wearable electronics (smart textiles). The unique and promising advantages of smart electronic textiles are highlighted by comparing them with the conventional planar counterparts. The main kinds of smart electronic textiles based on different functionalities, namely the generation, storage, and utilization of electricity, are then discussed with an emphasis on the use of functional materials. The remaining challenges are summarized together with important new directions to provide some useful clues for the future development of smart electronic textiles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cellulose nanocrystals, nanofibers, and their composites as renewable smart materials

NASA Astrophysics Data System (ADS)

Kim, Jaehwan; Zhai, Lindong; Mun, Seongcheol; Ko, Hyun-U.; Yun, Young-Min

2015-04-01

Cellulose is one of abundant renewable biomaterials in the world. Over 1.5 trillion tons of cellulose is produced per year in nature by biosynthesis, forming microfibrils which in turn aggregate to form cellulose fibers. Using new effective methods these microfibrils can be disintegrated from the fibers to nanosized materials, so called cellulose nanocrystal (CNC) and cellulose nanofiber (CNF). The CNC and CNF have extremely good strength properties, dimensional stability, thermal stability and good optical properties on top of their renewable behavior, which can be a building block of new materials. This paper represents recent advancement of cellulose nanocrystals and cellulose nanofibers, followed by their possibility for smart materials. Natural behaviors, extraction, modification of cellulose nanocrystals and fibers are explained and their synthesis with nanomaterials is introduced, which is necessary to meet the technological requirements for smart materials. Also, its challenges are addressed.

Printable semiconductor structures and related methods of making and assembling

DOEpatents

Nuzzo, Ralph G.; Rogers, John A.; Menard, Etienne; Lee, Keon Jae; Khang; , Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao; Ko, Heung Cho; Mack, Shawn

2013-03-12

The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

Printable semiconductor structures and related methods of making and assembling

DOEpatents

Nuzzo, Ralph G [Champaign, IL; Rogers, John A [Champaign, IL; Menard, Etienne [Durham, NC; Lee, Keon Jae [Tokyo, JP; Khang, Dahl-Young [Urbana, IL; Sun, Yugang [Westmont, IL; Meitl, Matthew [Raleigh, NC; Zhu, Zhengtao [Rapid City, SD; Ko, Heung Cho [Urbana, IL; Mack, Shawn [Goleta, CA

2011-10-18

The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

Printable semiconductor structures and related methods of making and assembling

DOEpatents

Nuzzo, Ralph G.; Rogers, John A.; Menard, Etienne; Lee, Keon Jae; Khang, Dahl-Young; Sun, Yugang; Meitl, Matthew; Zhu, Zhengtao; Ko, Heung Cho; Mack, Shawn

2010-09-21

The present invention provides a high yield pathway for the fabrication, transfer and assembly of high quality printable semiconductor elements having selected physical dimensions, shapes, compositions and spatial orientations. The compositions and methods of the present invention provide high precision registered transfer and integration of arrays of microsized and/or nanosized semiconductor structures onto substrates, including large area substrates and/or flexible substrates. In addition, the present invention provides methods of making printable semiconductor elements from low cost bulk materials, such as bulk silicon wafers, and smart-materials processing strategies that enable a versatile and commercially attractive printing-based fabrication platform for making a broad range of functional semiconductor devices.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harper, Jason; Dobrzynski, Daniel S.

A smart charging system for charging a plug-in electric vehicle (PEV) includes an electric vehicle supply equipment (EVSE) configured to supply electrical power to the PEV through a smart charging module coupled to the EVSE. The smart charging module comprises an electronic circuitry which includes a processor. The electronic circuitry includes electronic components structured to receive electrical power from the EVSE, and supply the electrical power to the PEV. The electronic circuitry is configured to measure a charging parameter of the PEV. The electronic circuitry is further structured to emulate a pulse width modulated signal generated by the EVSE. Themore » smart charging module can also include a first coupler structured to be removably couple to the EVSE and a second coupler structured to be removably coupled to the PEV.« less

Simultaneous Vibration Suppression and Energy Harvesting

DTIC Science & Technology

2013-08-15

D.J., 2011. “Modeling and Analysis of Piezoelectric Energy Harvesting from Aeroelastic Vibrations Using the Doublet-Lattice Method,” ASME Journal...Friswell, M. I., and Inman, D. J., 2009, “ Piezoelectric Energy Harvesting from Broadband Random Vibrations ,” Smart Materials and Structures, Vol. 18...and Electrode Configuration on Piezoelectric Energy Harvesting from Cantilevered Beams,” ASME Journal of Vibration and Acoustics, Vol. 131, No. 1, pp

Active Vibration Reduction of Titanium Alloy Fan Blades (FAN1) Using Piezoelectric Materials

NASA Technical Reports Server (NTRS)

Choi, Benjamin; Kauffman, Jeffrey; Duffy, Kirsten; Provenza, Andrew; Morrison, Carlos

2010-01-01

The NASA Glenn Research Center is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this paper, a digital resonant control technique emulating passive shunt circuits is used to demonstrate vibration reduction of FAN1 Ti real fan blade at the several target modes. Single-mode control and multi-mode control using one piezoelectric material are demonstrated. Also a conceptual study of how to implement this digital control system into the rotating fan blade is discussed.

The use of a deformable photonic crystal for millimeter-wave beam steering

NASA Astrophysics Data System (ADS)

Lin, Shawn-Yu; Yang, Zu-Po; Chen, Mingfeng; Bur, James A.; Levitan, A.; Kosowsky, Lester H.

2008-01-01

A deformable photonic band gap (PBG) material is theoretically proposed as a transmissive element for beam steering at 77GHz. The deformation may be achieved by integrating microsprings (as spacers) into a one-dimensional PBG structure. This PBG material can produce a specific phase shift dependent on its spacer thickness. By varying the spacer thickness, we generate a continuous phase gradient across the element. Such a PBG device is experimentally realized, capable of beam deflection of up to ±15° and suitable for beam scanning for smart automobile radar application.

Piezoelectric paints as one approach to smart structural materials with health-monitoring capabilities

NASA Astrophysics Data System (ADS)

Egusa, Shigenori; Iwasawa, Naozumi

1998-08-01

Piezoelectric paints have a potential to change a conventional structural material into an intelligent material system with health-monitoring capabilities such as vibration sensing and damage detection. Such paints were prepared using lead zirconate titanate (PZT) ceramic powder as a pigment and epoxy resin as a binder. The obtained paints were coated on aluminum test specimens, and were cured at room temperature or at 150 0964-1726/7/4/002/img5, thus forming the paint films having different thicknesses of 25-300 0964-1726/7/4/002/img6. These films were then poled at room temperature, and were evaluated with regard to the sensitivities as vibration and acoustic emission sensors in the frequency ranges of 0-250 Hz and 0-1.0 MHz, respectively. This paper mainly describes the effects of the film thickness and the cure temperature on the poling behavior of the PZT/epoxy paint film. This paper describes also the application of the paint film as a vibration modal sensor integrated into a structural material.

Self-assembly of colloid-cholesteric composites provides a possible route to switchable optical materials

NASA Astrophysics Data System (ADS)

Stratford, K.; Henrich, O.; Lintuvuori, J. S.; Cates, M. E.; Marenduzzo, D.

2014-06-01

Colloidal particles dispersed in liquid crystals can form new materials with tunable elastic and electro-optic properties. In a periodic ‘blue phase’ host, particles should template into colloidal crystals with potential uses in photonics, metamaterials and transformational optics. Here we show by computer simulation that colloid/cholesteric mixtures can give rise to regular crystals, glasses, percolating gels, isolated clusters, twisted rings and undulating colloidal ropes. This structure can be tuned via particle concentration, and by varying the surface interactions of the cholesteric host with both the particles and confining walls. Many of these new materials are metastable: two or more structures can arise under identical thermodynamic conditions. The observed structure depends not only on the formulation protocol but also on the history of an applied electric field. This new class of soft materials should thus be relevant to design of switchable, multistable devices for optical technologies such as smart glass and e-paper.

Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials

PubMed Central

Ramakrishnan, Manjusha; Rajan, Ginu; Semenova, Yuliya; Farrell, Gerald

2016-01-01

This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements. PMID:26784192

Application of smart BFRP bars with distributed fiber optic sensors into concrete structures

NASA Astrophysics Data System (ADS)

Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Wu, Gang; Zhao, Lihua; Song, Shiwei

2010-04-01

In this paper, the self-sensing and mechanical properties of concrete structures strengthened with a novel type of smart basalt fiber reinforced polymer (BFRP) bars were experimentally studied, wherein the sensing element is Brillouin scattering-based distributed optical fiber sensing technique. First, one of the smart bars was applied to strengthen a 2m concrete beam under a 4-points static loading manner in the laboratory. During the experiment, the bar can measure the inner strain changes and monitor the randomly distributed cracks well. With the distributed strain information along the bar, the distributed deformation of the beam can be calculated, and the structural health can be monitored and evaluated as well. Then, two smart bars with a length of about 70m were embedded into a concrete airfield pavement reinforced by long BFRP bars. In the field test, all the optical fiber sensors in the smart bars survived the whole concrete casting process and worked well. From the measured data, the concrete cracks along the pavement length can be easily monitored. The experimental results also confirmed that the bars can strengthen the structures especially after the yielding of steel bars. All the results confirm that this new type of smart BFRP bars show not only good sensing performance but also mechanical performance in the concrete structures.

Design of a Magnetostrictive-Hydraulic Actuator Considering Nonlinear System Dynamics and Fluid-Structure Coupling

NASA Astrophysics Data System (ADS)

Larson, John Philip

Smart material electro-hydraulic actuators (EHAs) utilize fluid rectification via one-way check valves to amplify the small, high-frequency vibrations of certain smart materials into large motions of a hydraulic cylinder. Although the concept has been demonstrated in previously, the operating frequency of smart material EHA systems has been limited to a small fraction of the available bandwidth of the driver materials. The focus of this work is to characterize and model the mechanical performance of a magnetostrictive EHA considering key system components: rectification valves, smart material driver, and fluid-system components, leading to an improved actuator design relative to prior work. The one-way valves were modeled using 3-D finite element analysis, and their behavior was characterized experimentally by static and dynamic experimental measurement. Taking into account the effect of the fluid and mechanical conditions applied to the valves within the pump, the dynamic response of the valve was quantified and applied to determine rectification bandwidth of different valve configurations. A novel miniature reed valve, designed for a frequency response above 10~kHz, was fabricated and tested within a magnetostrictive EHA. The nonlinear response of the magnetostrictive driver, including saturation and hysteresis effects, was modeled using the Jiles-Atherton approach to calculate the magnetization and the resulting magnetostriction based on the applied field calculated within the rod from Maxwell's equations. The dynamic pressure response of the fluid system components (pumping chamber, hydraulic cylinder, and connecting passages) was measured over a range of input frequencies. For the magnetostrictive EHA tested, the peak performance frequency was found to be limited by the fluid resonances within the system. A lumped-parameter modeling approach was applied to model the overall behavior of a magnetostrictive EHA, incorporating models for the reed valve response, nonlinear magnetostrictive behavior, and fluid behavior (including inertia and compliance). This model was validated by experimental study of a magnetostrictive EHA with a reduced volume manifold. The model was subsequently applied to design a compact magnetostrictive EHA for aircraft applications. Testing of the system shows that the output performance increases with frequency up to a peak unloaded flow rate of 100 cm3/s (6.4 cu in/s) at 1200 Hz, which is a 100% to 500% increase over previous state-of-the-art systems. A blocked differential pressure of 12.1 MPa (1750 psi) was measured, resulting in a power capacity of 310 W, more than 100 W higher than previously reported values. The design and modeling approach used to scale up the performance to create a compact aircraft EHA can also be applied to reduce the size and weight of smart material EHAs for lower power level applications.

Jahn-Teller crystals - new class of smart materials

NASA Astrophysics Data System (ADS)

Kaplan, M. D.; Zimmerman, G. O.

2017-05-01

Jahn-Teller crystals represent a promising class in the search for new smart materials. Jahn- Teller multiferroics are of a special interest. We show that the properties of these crystals are not only “of interest for future applications”, but are already used and protected by various patents. Special attention is paid to some new results on magnetic shape memory effects in dielectrics because the physics of the corresponding materials is not yet completely clarified.

Galerkin finite element scheme for magnetostrictive structures and composites

NASA Astrophysics Data System (ADS)

Kannan, Kidambi Srinivasan

The ever increasing-role of magnetostrictives in actuation and sensing applications is an indication of their importance in the emerging field of smart structures technology. As newer, and more complex, applications are developed, there is a growing need for a reliable computational tool that can effectively address the magneto-mechanical interactions and other nonlinearities in these materials and in structures incorporating them. This thesis presents a continuum level quasi-static, three-dimensional finite element computational scheme for modeling the nonlinear behavior of bulk magnetostrictive materials and particulate magnetostrictive composites. Models for magnetostriction must deal with two sources of nonlinearities-nonlinear body forces/moments in equilibrium equations governing magneto-mechanical interactions in deformable and magnetized bodies; and nonlinear coupled magneto-mechanical constitutive models for the material of interest. In the present work, classical differential formulations for nonlinear magneto-mechanical interactions are recast in integral form using the weighted-residual method. A discretized finite element form is obtained by applying the Galerkin technique. The finite element formulation is based upon three dimensional eight-noded (isoparametric) brick element interpolation functions and magnetostatic infinite elements at the boundary. Two alternative possibilities are explored for establishing the nonlinear incremental constitutive model-characterization in terms of magnetic field or in terms of magnetization. The former methodology is the one most commonly used in the literature. In this work, a detailed comparative study of both methodologies is carried out. The computational scheme is validated, qualitatively and quantitatively, against experimental measurements published in the literature on structures incorporating the magnetostrictive material Terfenol-D. The influence of nonlinear body forces and body moments of magnetic origin, on the response of magnetostrictive structures to complex mechanical and magnetic loading conditions, is carefully examined. While monolithic magnetostrictive materials have been commercially-available since the late eighties, attention in the smart structures research community has recently focussed upon building and using magnetostrictive particulate composite structures for conventional actuation applications and novel sensing methodologies in structural health monitoring. A particulate magnetostrictive composite element has been developed in the present work to model such structures. This composite element incorporates interactions between magnetostrictive particles by combining a numerical micromechanical analysis based on magneto-mechanical Green's functions, with a homogenization scheme based upon the Mori-Tanaka approach. This element has been applied to the simulation of particulate actuators and sensors reported in the literature. Simulation results are compared to experimental data for validation purposes. The computational schemes developed, for bulk materials and for composites, are expected to be of great value to researchers and designers of novel applications based on magnetostrictives.

Breathable ‘Second Skin’ for Smart Uniforms

ScienceCinema

Fornasiero, Francesco

2018-01-16

Aiming to protect soldiers from biological and chemical threats, a team of Lawrence Livermore National Laboratory scientists have created a material that is highly breathable yet protective from biological agents. This material is the first key component of futuristic smart uniforms that also will respond to and protect from environmental chemical hazards.

Efficient Flame Detection and Early Warning Sensors on Combustible Materials Using Hierarchical Graphene Oxide/Silicone Coatings.

PubMed

Wu, Qian; Gong, Li-Xiu; Li, Yang; Cao, Cheng-Fei; Tang, Long-Cheng; Wu, Lianbin; Zhao, Li; Zhang, Guo-Dong; Li, Shi-Neng; Gao, Jiefeng; Li, Yongjin; Mai, Yiu-Wing

2018-01-23

Design and development of smart sensors for rapid flame detection in postcombustion and early fire warning in precombustion situations are critically needed to improve the fire safety of combustible materials in many applications. Herein, we describe the fabrication of hierarchical coatings created by assembling a multilayered graphene oxide (GO)/silicone structure onto different combustible substrate materials. The resulting coatings exhibit distinct temperature-responsive electrical resistance change as efficient early warning sensors for detecting abnormal high environmental temperature, thus enabling fire prevention below the ignition temperature of combustible materials. After encountering a flame attack, we demonstrate extremely rapid flame detection response in 2-3 s and excellent flame self-extinguishing retardancy for the multilayered GO/silicone structure that can be synergistically transformed to a multiscale graphene/nanosilica protection layer. The hierarchical coatings developed are promising for fire prevention and protection applications in various critical fire risk and related perilous circumstances.

Modelling sodium cobaltate by mapping onto magnetic Ising model

NASA Astrophysics Data System (ADS)

Gemperline, Patrick; Morris, David Jonathan Pryce

Fast Ion conductors are a class of crystals that are frequently used as battery materials, especially in smart phones, laptops, and other portable devices. Sodium Cobalt Oxide, NaxCoO2, falls into this class of crystals, but is unique because it possesses the ability to act as a thermoelectric material and a superconductor at different concentrations of Na+. The crystal lattice is mapped onto an Ising Magnetic Spin model and a Monte-Carol Simulation is used to find the most energetically favorable configuration of spins. This spin configuration is mapped back to the crystal lattice resulting in the most stable crystal structure of Sodium Cobalt Oxide at various concentrations. Knowing the atomic structures of the crystals will aid in the research of the materials capabilities and the possible uses of the material commercially. Ohio Supercomputer Center. 1987. Ohio Supercomputer Center. Columbus OH: Ohio Supercomputer Center. and the John Hauck Foundation.

A comprehensive review of select smart polymeric and gel actuators for soft mechatronics and robotics applications: fundamentals, freeform fabrication, and motion control

NASA Astrophysics Data System (ADS)

Carrico, James D.; Tyler, Tom; Leang, Kam K.

2017-10-01

Smart polymeric and gel actuators change shape or size in response to stimuli like electricity, heat, or light. These smart polymeric- and gel-based actuators are compliant and well suited for development of soft mechatronic and robotic devices. This paper provides a thorough review of select smart polymeric and gel actuator materials where an automated and freeform fabrication process, like 3D printing, is exploited to create custom shaped monolithic devices. In particular, the advantages and limitations, examples of applications, manufacturing and fabrication techniques, and methods for actuator control are discussed. Finally, a rigorous comparison and analysis of some of the advantages and limitations, as well as manufacturing processes, for these materials, are presented.

Ignitable heterogeneous stratified structure for the propagation of an internal exothermic chemical reaction along an expanding wavefront and method of making same

DOEpatents

Barbee, T.W. Jr.; Weihs, T.

1996-07-23

A multilayer structure has a selectable, (1) propagating reaction front velocity V, (2) reaction initiation temperature attained by application of external energy, and (3) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as igniters, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t{sub i}, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D{sup n}){times}[1-(t{sub i}/D)] and n is about 0.8 to 1.2. 8 figs.

Ignitable heterogeneous stratified structure for the propagation of an internal exothermic chemical reaction along an expanding wavefront and method of making same

DOEpatents

Barbee, Jr., Troy W.; Weihs, Timothy

1996-01-01

A multilayer structure has a selectable, (i) propagating reaction front velocity V, (ii) reaction initiation temperature attained by application of external energy and (iii) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as ignitors, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t.sub.i, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D.sup.n).times.[1-(t.sub.i /D)] and n is about 0.8 to 1.2.

Development of smart wave mitigation structure using array of poles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Asanuma, Hiroshi

2017-05-01

This paper describes reduction of water flow velocity by array of poles as a new wave mitigation structure. This structure is based on tsunami mitigation coastal forest. As natural forests have many problems such as low fraction of trees, low visibility of ocean waves, low strength, long of time to grow, and so on. To cope with these problems, a new wave mitigation structure has been developed, which are intended to add better capability of high wave or tsunami mitigation effect to actual ones by optimizing various parameters such as configuration, distribution density and material properties. In this study, the effect of type of material and its combination were mainly investigated. According to the results, reduction rate of the flow velocity increases with increasing number of rows for each material up to a certain level, and that of poles having lower Young's modulus is generally higher than that of those having higher Young's modulus. The effect of combination of materials was also investigated and drastic increase of mitigation effect was found when soft and hard poles were combined.

Adaptive Learning in Smart Cities--The Cases of Catania and Helsinki

ERIC Educational Resources Information Center

Laitinen, Ilpo; Piazza, Roberta; Stenvall, Jari

2017-01-01

Our research is a comparative qualitative study. The material has been gathered from the cities of Helsinki and Catania. The target cities showcase varied successes and models of smart cities. In the cities, key people involved in the smart city concept--with different kinds of professional backgrounds--were interviewed, both individually and in…

Fuzzy Modal Control Applied to Smart Composite Structure

NASA Astrophysics Data System (ADS)

Koroishi, E. H.; Faria, A. W.; Lara-Molina, F. A.; Steffen, V., Jr.

2015-07-01

This paper proposes an active vibration control technique, which is based on Fuzzy Modal Control, as applied to a piezoelectric actuator bonded to a composite structure forming a so-called smart composite structure. Fuzzy Modal Controllers were found to be well adapted for controlling structures with nonlinear behavior, whose characteristics change considerably with respect to time. The smart composite structure was modelled by using a so called mixed theory. This theory uses a single equivalent layer for the discretization of the mechanical displacement field and a layerwise representation of the electrical field. Temperature effects are neglected. Due to numerical reasons it was necessary to reduce the size of the model of the smart composite structure so that the design of the controllers and the estimator could be performed. The role of the Kalman Estimator in the present contribution is to estimate the modal states of the system, which are used by the Fuzzy Modal controllers. Simulation results illustrate the effectiveness of the proposed vibration control methodology for composite structures.

Sandwiched gold/PNIPAm/gold microstructures for smart plasmonics application: towards the high detection limit and Raman quantitative measurements.

PubMed

Elashnikov, R; Mares, D; Podzimek, T; Švorčík, V; Lyutakov, O

2017-08-07

A smart plasmonic sensor, comprising a layer of a stimuli-responsive polymer sandwiched between two gold layers, is reported. As a stimuli-responsive material, a monolayer of poly(N-isopropylacrylamide) (PNIPAm) crosslinked globules is used. A quasi-periodic structure of the top gold layer facilitates efficient excitation and serves as a support for plasmon excitation and propagation. The intermediate layer of PNIPAm efficiently entraps targeted molecules from solutions. The sensor structure was optimized for efficient light focusing in the "active" PNIPAm layer. The optimization was based on the time-resolved finite-element simulations, which take into account the thickness of gold layers, size of PNIPAm globules and Raman excitation wavelength (780 nm). The prepared structures were characterized using SEM, AFM, UV-Vis refractometry and goniometry. Additional AFM scans were performed in water at two temperatures corresponding to the collapsed and swollen PNIPAm states. The Raman measurements demonstrate a high detection limit and perfect reproducibility of the Raman scattering signal for the prepared sensor. In addition, the use of created SERS structures for the detection of relevant molecules in the medical, biological and safety fields was demonstrated.

A Probabilistic Design Method Applied to Smart Composite Structures

NASA Technical Reports Server (NTRS)

Shiao, Michael C.; Chamis, Christos C.

1995-01-01

A probabilistic design method is described and demonstrated using a smart composite wing. Probabilistic structural design incorporates naturally occurring uncertainties including those in constituent (fiber/matrix) material properties, fabrication variables, structure geometry and control-related parameters. Probabilistic sensitivity factors are computed to identify those parameters that have a great influence on a specific structural reliability. Two performance criteria are used to demonstrate this design methodology. The first criterion requires that the actuated angle at the wing tip be bounded by upper and lower limits at a specified reliability. The second criterion requires that the probability of ply damage due to random impact load be smaller than an assigned value. When the relationship between reliability improvement and the sensitivity factors is assessed, the results show that a reduction in the scatter of the random variable with the largest sensitivity factor (absolute value) provides the lowest failure probability. An increase in the mean of the random variable with a negative sensitivity factor will reduce the failure probability. Therefore, the design can be improved by controlling or selecting distribution parameters associated with random variables. This can be implemented during the manufacturing process to obtain maximum benefit with minimum alterations.

Smart Polymeric Hydrogels for Cartilage Tissue Engineering: A Review on the Chemistry and Biological Functions.

PubMed

Eslahi, Niloofar; Abdorahim, Marjan; Simchi, Abdolreza

2016-11-14

Stimuli responsive hydrogels (SRHs) are attractive bioscaffolds for tissue engineering. The structural similarity of SRHs to the extracellular matrix (ECM) of many tissues offers great advantages for a minimally invasive tissue repair. Among various potential applications of SRHs, cartilage regeneration has attracted significant attention. The repair of cartilage damage is challenging in orthopedics owing to its low repair capacity. Recent advances include development of injectable hydrogels to minimize invasive surgery with nanostructured features and rapid stimuli-responsive characteristics. Nanostructured SRHs with more structural similarity to natural ECM up-regulate cell-material interactions for faster tissue repair and more controlled stimuli-response to environmental changes. This review highlights most recent advances in the development of nanostructured or smart hydrogels for cartilage tissue engineering. Different types of stimuli-responsive hydrogels are introduced and their fabrication processes through physicochemical procedures are reported. The applications and characteristics of natural and synthetic polymers used in SRHs are also reviewed with an outline on clinical considerations and challenges.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hong; Wang, Jy-An John; Ren, Fei

Integration of smart patches into full-tension splice connectors in overhead power transmission lines was investigated. Lead zirconate titanate (PZT) -5A was used as a smart material and an aluminum beam was used as a host structure. Negative electrode termination was examined by using copper adhesive tape and direct bonding methods. Various commercial adhesives were studied for PZT integration onto the host structure. Aluminum beam specimens with integrated PZT smart patches were tested under thermal cycling at a temperature of 125 C, which is the higher-end temperature experienced by in-service aluminum conductor steel-reinforced cables. Electromechanical impedance (EMI) measurements were conducted atmore » room temperature, and the root mean square deviation (RMSD) of the conductance signals was used to analyze the EMI data. It has been shown that the negative electrode method has an important effect on the performance of the integrated PZT. The PZT displayed more susceptibility to cracking when copper tape was used than when direct bonding was used. The reliability of PZT in direct bonding depended on the adhesives used in bonding layers. Although a hard alumina based adhesive can lead to cracking of the PZT, a high-temperature epoxy with adequate flexibility, such as Duralco 4538D, can provide the desired performance under target thermal cycling conditions. The RMSD parameter can characterize conductance signatures effectively. It also was demonstrated that RMSD can be used to quantify the fatigue of the PZT integration system, although RMSD is used primarily as a damage index in monitoring structural health.« less

System requirements specification for SMART structures mode

NASA Technical Reports Server (NTRS)

1992-01-01

Specified here are the functional and informational requirements for software modules which address the geometric and data modeling needs of the aerospace structural engineer. The modules are to be included as part of the Solid Modeling Aerospace Research Tool (SMART) package developed for the Vehicle Analysis Branch (VAB) at the NASA Langley Research Center (LaRC). The purpose is to precisely state what the SMART Structures modules will do, without consideration of how it will be done. Each requirement is numbered for reference in development and testing.

Facile Fabrication of Electrically Conductive Low-Density Polyethylene/Carbon Fiber Tubes for Novel Smart Materials via Multiaxial Orientation.

PubMed

Li, Yijun; Nie, Min; Wang, Qi

2018-01-10

Electromechanical sensors are indispensable components in functional devices and robotics application. However, the fabrication of the sensors still maintains a challenging issue that high percolation threshold and easy failure of conductive network are derived from uniaxial orientation of conductive fillers in practical melt processing. Herein, we reported a facile fabrication method to prepare a multiaxial low-density polyethylene (LDPE)/carbon fibers (CFs) tube with bidirectional controllable electrical conductivity and sensitive strain-responsive performance via rotation extrusion technology. The multidimensional helical flow is confirmed in the reverse rotation extrusion, and the CFs readily respond to the flow field leading to a multiaxial orientation in the LDPE matrix. In contrast to uniaxial LDPE/CF composites, which perform a "head to head" conjunction, multiaxial-orientated CF networks exhibit a unique multilayer structure in which the CFs with distinct orientation direction intersect in the interface, endowing the LDPE/CF composites with a low percolation threshold (15 wt %) to those of the uniaxial ones (∼35 wt %). The angles between two axes play a vital role in determining the density of the conductive networks in the interface, which is predominant in tuning the bending-responsive behaviors with a gauge factor range from 12.5 to 56.3 and the corresponding linear respond region from ∼15 to ∼1%. Such a superior performance of conductive LDPE/CF tube confirms that the design of multiaxial orientation paves a novel way to facile fabrication of advanced cost-effective CF-based smart materials, shedding light on promising applications such as smart materials and intelligent engineering monitoring.

Smart composites with embedded shape memory alloy actuators and fibre Bragg grating sensors: activation and control

NASA Astrophysics Data System (ADS)

Balta, J. A.; Bosia, F.; Michaud, V.; Dunkel, G.; Botsis, J.; Månson, J.-A.

2005-08-01

This paper describes the production of an adaptive composite by embedding thin pre-strained shape memory alloy actuators into a Kevlar-epoxy host material. In order to combine the activation and sensing capabilities, fibre Bragg grating sensors are also embedded into the specimens, and the strain measured in situ during activation. The effect of manufacturing conditions, and hence of the initial stress state in the composite before activation, on the magnitude of the measured strains is discussed. The results of stress and strain simulations are compared with experimental data, and guidelines are provided for the optimization of the composite. Finally, a pilot experiment is carried out to provide an example of how a strain-stabilizing feedback mechanism can be implemented in the smart structure.

DNA Nanostructures as Smart Drug-Delivery Vehicles and Molecular Devices.

PubMed

Linko, Veikko; Ora, Ari; Kostiainen, Mauri A

2015-10-01

DNA molecules can be assembled into custom predesigned shapes via hybridization of sequence-complementary domains. The folded structures have high spatial addressability and a tremendous potential to serve as platforms and active components in a plethora of bionanotechnological applications. DNA is a truly programmable material, and its nanoscale engineering thus opens up numerous attractive possibilities to develop novel methods for therapeutics. The tailored molecular devices could be used in targeting cells and triggering the cellular actions in the biological environment. In this review we focus on the DNA-based assemblies - primarily DNA origami nanostructures - that could perform complex tasks in cells and serve as smart drug-delivery vehicles in, for example, cancer therapy, prodrug medication, and enzyme replacement therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

A precision structured smart hydrogel for sensing applications

NASA Astrophysics Data System (ADS)

Menges, J.; Kleinschmidt, P.; Bart, H.-J.; Oesterschulze, E.

2017-10-01

We report on a macroinitiator based smart hydrogel film applied on a microcantilever for sensing applications. The studied hydrogel features a comparatively wide dynamic range for changes in the electrolyte's ionic strength. Furthermore, it offers a simple spin coating process for thin film deposition as well as the capability to obtain high aspect ratio microstructures by reactive ion etching. This makes the hydrogel compatible to microelectromechanical system integration. As a proof of concept, we study the response of hydrogel functionalized cantilevers in aqueous sodium chloride solutions of varying ionic strength. In contrast to the majority of hydrogel materials reported in the literature, we found that our hydrogel still responds in high ionic strength environments. This may be of future interest for sensing e.g., in sea water or physiological environments like urine.

Smart photonic coating for civil engineering field: for a future inspection technology on concrete bridge

NASA Astrophysics Data System (ADS)

Fudouzi, Hiroshi; Tsuchiya, Koichi; Todoroki, Shin-ichi; Hyakutake, Tsuyoshi; Nitta, Hiroyuki; Nishizaki, Itaru; Tanaka, Yoshikazu; Ohya, Takao

2017-04-01

Here we will propose the conceptual new idea of the inspection of concrete bridge using smart materials and mobile IoT system. We apply opal photonic crystal film to detect cracks on concrete infrastructures. High quality opal photonic crystal films were coated on black color PET sheet over 1000 cm2 area. The opal film sheet was cut and adhered to concrete or mortar test pieces by epoxy resin. In the tensile test, the structural color of the opal sheet was changed when the crack was formed. As a demonstration, we have installated the opal film sheet on the wall of the concrete bridge. Our final purpose is the color change will be recorded by portable CCD devices, and send to expert via IoT network.

Smart drug release systems based on stimuli-responsive polymers.

PubMed

Qing, Guangyan; Li, Minmin; Deng, Lijing; Lv, Ziyu; Ding, Peng; Sun, Taolei

2013-07-01

Stimuli-responsive polymers could respond to external stimuli, such as temperature, pH, photo-irradiation, electric field, biomolecules in solution, etc., which further induce reversible transformations in the structures and conformations of polymers, providing an excellent platform for controllable drug release, while the accuracy of drug delivery could obtain obvious improvement in this system. In this review, recent progresses in the drug release systems based on stimuli-responsive polymers are summarized, in which drugs can be released in an intelligent mode with high accuracy and efficiency, while potential damages to normal cells and tissues can also be effectively prevented owing to the unique characteristics of materials. Moreover, we introduce some smart nanoparticles-polymers conjugates and drug release devices, which are especially suitable for the long-term sustained drug release.

High-resolution high-sensitivity and truly distributed optical frequency domain reflectometry for structural crack detection

NASA Astrophysics Data System (ADS)

Li, Wenhai; Bao, Xiaoyi; Chen, Liang

2014-05-01

Optical Frequency Domain Reflectometry (OFDR) with the use of polarization maintaining fiber (PMF) is capable of distinguishing strain and temperature, which is critical for successful field applications such as structural health monitoring (SHM) and smart material. Location-dependent measurement sensitivities along PMF are compensated by cross- and auto-correlations measurements of the spectra form a distributed parameter matrix. Simultaneous temperature and strain measurement accuracy of 1μstrain and 0.1°C is achieved with 2.5mm spatial resolution in over 180m range.

Design of a 4D Printing System Using Thermal Sensitive Smart Materials and Photoactivated Shape Changing Polymers

NASA Astrophysics Data System (ADS)

Leist, Steven Kyle

4D printing is an emerging additive manufacturing technology that combines 3D printing with smart materials. Current 3D printing technology can print objects with a multitude of materials; however, these objects are usually static, geometrically permanent, and not suitable for multi-functional use. The 4D printed objects can change their shape over time when exposed to different external stimuli such as heat, pressure, magnetic fields, or moisture. In this research, heat and light reactive smart materials are explored as a 4D printing materials. Synthetization of a material that actuates when exposed to stimulus can be a very difficult process, and merging that same material with the ability to be 3D printed can be further difficult. A common 3D printing thermoplastic, poly(lactic) acid (PLA), is used as a shape memory material that is 3D printed using a fused deposition machine (FDM) and combined with nylon fabric for the exploration of smart textiles. The research shows that post printed PLA possesses shape memory properties depending on the thickness of the 3D printed material and the activation temperature. PLA can be thermomechanically trained into temporary shapes and return to its original shape when exposed to high temperatures. PLA can be 3D printed onto nylon fabrics for the creation of the smart textiles. Additionally, a photoisomerable shape changing material is explored because light activation is wireless, controllable, focusable, abundant, causes rapid shape change of the smart material, and induces reversible shape change in the material. This study supports the fundamental research to generate knowledge needed for synthesis of a novel azobenzene shape changing polymer (SCP) and integrating this smart material into objects printed with a 4D printing process using syringe printing. Multiple versions of azobenzene SCP are synthesized that actuate when exposed to 365 nm and 455 nm light. Two SCPs, MeOABHx and DR1Hx, are selected for the 4D printing research because of their ability to photoisomerize at room temperature and 3D printability. The physical properties of these polymers are characterized, photomechanical bending tests are performed, and the photo-generated stress is measured using a dynamic mechanical analyzer (DMA). The SCPs are deposited onto a passive layer to create bilayer films in order to actuate. The photomechanical efficiency of bilayer films is evaluated depending on the thickness of the passive layer film, type of azobenzene SCP, wavelength of the light source, intensity of the light source, and distance between the light and films. 4D printing can be used to streamline the design and manufacturing process of actuating parts. Complex heavy parts can be removed from actuation systems such as onboard power storage, motors, sensors, and processors by embedding these capabilities into the material themselves. This reduces the amount of required parts, the amount of materials, and reduces the cost of producing these parts. 4D printed products possess the properties of programmability, reaction and adaption to their environment, and automation. Therefore, they can find wider applications including foldable unmanned aerial vehicles, artificial muscles, grippers, biomedical drug delivery systems, stents, and minimally invasive surgeries.

Big–deep–smart data in imaging for guiding materials design

DOE PAGES

Kalinin, Sergei V.; Sumpter, Bobby G.; Archibald, Richard K.

2015-09-23

Harnessing big data, deep data, and smart data from state-of-the-art imaging might accelerate the design and realization of advanced functional materials. Here we discuss new opportunities in materials design enabled by the availability of big data in imaging and data analytics approaches, including their limitations, in material systems of practical interest. We specifically focus on how these tools might help realize new discoveries in a timely manner. Such methodologies are particularly appropriate to explore in light of continued improvements in atomistic imaging, modelling and data analytics methods.

Big-deep-smart data in imaging for guiding materials design.

PubMed

Kalinin, Sergei V; Sumpter, Bobby G; Archibald, Richard K

2015-10-01

Harnessing big data, deep data, and smart data from state-of-the-art imaging might accelerate the design and realization of advanced functional materials. Here we discuss new opportunities in materials design enabled by the availability of big data in imaging and data analytics approaches, including their limitations, in material systems of practical interest. We specifically focus on how these tools might help realize new discoveries in a timely manner. Such methodologies are particularly appropriate to explore in light of continued improvements in atomistic imaging, modelling and data analytics methods.

Big-deep-smart data in imaging for guiding materials design

NASA Astrophysics Data System (ADS)

Kalinin, Sergei V.; Sumpter, Bobby G.; Archibald, Richard K.

2015-10-01

Harnessing big data, deep data, and smart data from state-of-the-art imaging might accelerate the design and realization of advanced functional materials. Here we discuss new opportunities in materials design enabled by the availability of big data in imaging and data analytics approaches, including their limitations, in material systems of practical interest. We specifically focus on how these tools might help realize new discoveries in a timely manner. Such methodologies are particularly appropriate to explore in light of continued improvements in atomistic imaging, modelling and data analytics methods.

Big–deep–smart data in imaging for guiding materials design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinin, Sergei V.; Sumpter, Bobby G.; Archibald, Richard K.

Harnessing big data, deep data, and smart data from state-of-the-art imaging might accelerate the design and realization of advanced functional materials. Here we discuss new opportunities in materials design enabled by the availability of big data in imaging and data analytics approaches, including their limitations, in material systems of practical interest. We specifically focus on how these tools might help realize new discoveries in a timely manner. Such methodologies are particularly appropriate to explore in light of continued improvements in atomistic imaging, modelling and data analytics methods.

Nonlinear dynamic modeling for smart material electro-hydraulic actuator development

NASA Astrophysics Data System (ADS)

Larson, John P.; Dapino, Marcelo J.

2013-03-01

Smart material electro-hydraulic actuators use hydraulic rectification by one-way check valves to amplify the motion of smart materials, such as magnetostrictives and piezoelectrics, in order to create compact, lightweight actuators. A piston pump driven by a smart material is combined with a hydraulic cylinder to form a self-contained, power-by-wire actuator that can be used in place of a conventional hydraulic system without the need for hydraulic lines and a centralized pump. The performance of an experimental actuator driven by a 12.7 mm diameter, 114 mm length Terfenol-D rod is evaluated over a range of applied input frequencies, loads, and currents. The peak performance achieved is 37 W, moving a 220 N load at a rate of 17 cm/s and producing a blocked pressure of 12.5 MPa. Additional tests are conducted to quantify the dynamic behavior of the one-way reed valves using a scanning laser vibrometer to identify the frequency response of the reeds and the effect of the valve seat and fluid mass loading. A lumped-parameter model is developed for the system that includes valve inertia and fluid response nonlinearities, and the model results are compared with the experimental data.

FOREWORD: Shape Memory and Related Technologies

NASA Astrophysics Data System (ADS)

Liu, Yong

2005-10-01

The International Symposium on Shape Memory and Related Technologies (SMART2004) successfully took place in Singapore from November 24 to 26, 2004. SMART2004 aimed to provide a forum for presenting and discussing recent developments in the processing, characterization, application and performance prediction of shape memory materials, particularly shape memory alloys and magnetic shape memory materials. In recent years, we have seen a surge in the research and application of shape memory materials. This is due on the one hand to the successful applications of shape memory alloys (SMAs), particularly NiTi (nitinol), in medical practices and, on the other hand, to the discovery of magnetic shape memory (MSM) materials (or, ferromagnetic shape memory alloys, FSMAs). In recent years, applications of SMAs in various engineering practices have flourished owing to the unique combination of novel properties including high power density related to shape recovery, superelasticity with tunable hysteresis, high damping capacity combined with good fatigue resistance, excellent wear resistance due to unconventional deformation mechanisms (stress-induced phase transformation and martensite reorientation), and excellent biocompatibility and anticorrosion resistance, etc. In~the case of MSMs (or FSMAs), their giant shape change in a relatively low magnetic field has great potential to supplement the traditional actuation mechanisms and to have a great impact on the world of modern technology. Common mechanisms existing in both types of materials, namely thermoelastic phase transformation, martensite domain switching and their controlling factors, are of particular interest to the scientific community. Despite some successful applications, some fundamental issues remain unsatisfactorily understood. This conference hoped to link the fundamental research to engineering practices, and to further identify remaining problems in order to further promote the applications of shape memory materials in various demanding fields. Some top researchers from Asia, Australia, Europe and USA attended the meeting and gave oral presentations on both the fundamentals and applied aspects of SMAs and MSMs. Several prominent experts have delivered invited talks on the damping capacity of SMAs (J Van Humbeeck), SMA thin films (S Miyazaki), MSMs (V Lindross and O Söderberg) and SMA microtubes (Q P Sun). At the end of the Symposium, a panel discussion on various aspects of shape memory materials was held in the Nanyang Technological University. Comments, suggestions, opinions, discussions etc from all participants are greatly appreciated and acknowledged. I would like to thank all the participants for their valuable contributions toward the success of SMART2004, and thank all the session chairpersons for making this Symposium an event full of beneficial discussions. This special issue includes some of the manuscripts submitted to SMART2004. I want to express my deep gratitude to the editorial office of the journal of Smart Materials and Structures and all the referees for their great help in producing this special issue. This symposium has received support from the Institute of Materials (East Asia) and the School of Mechanical and Aerospace Engineering of the Nanyang Technological University. The following sponsors are gratefully acknowledged: Lee Foundation (Singapore) Accelrys Instron (Singapore Pte Ltd).

Layerwise Mechanics and Finite Elements for Smart Composite Structures with Piezoelectric Actuators and Sensors

NASA Technical Reports Server (NTRS)

Saravanos, Dimitris A.; Heyliger, Paul R.; Hopkins, Dale A.

1996-01-01

Recent developments on layerwise mechanics for the analysis of composite laminates and structures with piezoelectric actuators and sensors are reviewed. The mechanics implement layerwise representations of displacements and electric potential, and can model both the global and local electromechanical response of smart composite structures. The corresponding finite-element implementations for the static and dynamic analysis of smart piezoelectric composite structures are also summarized. Select application illustrate the accuracy, robustness and capability of the developed mechanics to capture the global and local dynamic response of thin and/or thick laminated piezoelectric plates.

Smart Materials Meet Multifunctional Biomedical Devices: Current and Prospective Implications for Nanomedicine.

PubMed

Genchi, Giada Graziana; Marino, Attilio; Tapeinos, Christos; Ciofani, Gianni

2017-01-01

With the increasing advances in the fabrication and in monitoring approaches of nanotechnology devices, novel materials are being synthesized and tested for the interaction with biological environments. Among them, smart materials in particular provide versatile and dynamically tunable platforms for the investigation and manipulation of several biological activities with very low invasiveness in hardly accessible anatomical districts. In the following, we will briefly recall recent examples of nanotechnology-based materials that can be remotely activated and controlled through different sources of energy, such as electromagnetic fields or ultrasounds, for their relevance to both basic science investigations and translational nanomedicine. Moreover, we will introduce some examples of hybrid materials showing mutually beneficial components for the development of multifunctional devices, able to simultaneously perform duties like imaging, tissue targeting, drug delivery, and redox state control. Finally, we will highlight challenging perspectives for the development of theranostic agents (merging diagnostic and therapeutic functionalities), underlining open questions for these smart nanotechnology-based devices to be made readily available to the patients in need.

A Dual-Responsive Nanocomposite toward Climate-Adaptable Solar Modulation for Energy-Saving Smart Windows.

PubMed

Lee, Heng Yeong; Cai, Yufeng; Bi, Shuguang; Liang, Yen Nan; Song, Yujie; Hu, Xiao Matthew

2017-02-22

In this work, a novel fully autonomous photothermotropic material made by hybridization of the poly(N-isopropylacrylamide) (PNIPAM) hydrogel and antimony-tin oxide (ATO) is presented. In this photothermotropic system, the near-infrared (NIR)-absorbing ATO acts as nanoheater to induce the optical switching of the hydrogel. Such a new passive smart window is characterized by excellent NIR shielding, a photothermally activated switching mechanism, enhanced response speed, and solar modulation ability. Systems with 0, 5, 10, and 15 atom % Sb-doped ATO in PNIPAM were investigated, and it was found that a PNIPAM/ATO nanocomposite is able to be photothermally activated. The 10 atom % Sb-doped PNIPAM/ATO exhibits the best response speed and solar modulation ability. Different film thicknesses and ATO contents will affect the response rate and solar modulation ability. Structural stability tests at 15 cycles under continuous exposure to solar irradiation at 1 sun intensity demonstrated the performance stability of such a photothermotropic system. We conclude that such a novel photothermotropic hybrid can be used as a new generation of autonomous passive smart windows for climate-adaptable solar modulation.

Timoshenko beam model for chiral materials

NASA Astrophysics Data System (ADS)

Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

2017-12-01

Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Timoshenko beam model for chiral materials

NASA Astrophysics Data System (ADS)

Ma, T. Y.; Wang, Y. N.; Yuan, L.; Wang, J. S.; Qin, Q. H.

2018-06-01

Natural and artificial chiral materials such as deoxyribonucleic acid (DNA), chromatin fibers, flagellar filaments, chiral nanotubes, and chiral lattice materials widely exist. Due to the chirality of intricately helical or twisted microstructures, such materials hold great promise for use in diverse applications in smart sensors and actuators, force probes in biomedical engineering, structural elements for absorption of microwaves and elastic waves, etc. In this paper, a Timoshenko beam model for chiral materials is developed based on noncentrosymmetric micropolar elasticity theory. The governing equations and boundary conditions for a chiral beam problem are derived using the variational method and Hamilton's principle. The static bending and free vibration problem of a chiral beam are investigated using the proposed model. It is found that chirality can significantly affect the mechanical behavior of beams, making materials more flexible compared with nonchiral counterparts, inducing coupled twisting deformation, relatively larger deflection, and lower natural frequency. This study is helpful not only for understanding the mechanical behavior of chiral materials such as DNA and chromatin fibers and characterizing their mechanical properties, but also for the design of hierarchically structured chiral materials.

Deployable structures using bistable reeled composites

NASA Astrophysics Data System (ADS)

Daton-Lovett, Andrew J.; Compton-Bishop, Quentin M.; Curry, Richard G.

2000-06-01

This paper describes an innovative, patented use of composite materials developed by RolaTube Technology Ltd. to make smart deployable structures. Bi-stable reeled composites (BRCs) can alternate between two stable forms; that of a strong, rigid structure and that of a compact coil of flat-wound material. Bi-stability arises as a result of the manipulation of Poisson's ratio and isotropy in the various layers of the material. BRCs are made of fiber- reinforced composite materials, most often with a thermoplastic matrix. A range of fibers and polymer matrices can be used according to the requirements of the operating environment. Samples of a BRC structure were constructed using layers of unidirectional, fiber-reinforced thermoplastic sheet with the layers at different angles. The whole assembly was then consolidated under conditions of elevated temperature and pressure. The properties of the BRC are described and the result of a series of experiments performed on the sample to determine the tensile strength of the BRC structure are reported. A full analysis using finite element methods is being undertaken in collaboration with the University of Cambridge, England. The first commercial use has been to fabricate boom and drive mechanisms for the remote inspection of industrial plant.

The Use of Smart phones in Ophthalmology.

PubMed

Zvornicanin, Edita; Zvornicanin, Jasmin; Hadziefendic, Bahrudin

2014-06-01

Smart phones are being increasingly used among health professionals. Ophthalmological applications are widely available and can turn smart phones into sophisticated medical devices. Smart phones can be useful instruments for the practice of evidence-based medicine, professional education, mobile clinical communication, patient education, disease self-management, remote patient monitoring or as powerful administrative tools. Several applications are available for different ophthalmological examinations that can assess visual acuity, color vision, astigmatism, pupil size, Amsler grid test and more. Smart phones can be useful ophthalmic devices for taking images of anterior and posterior eye segment. Professional literature and educational material for patients are easily available with use of smart phones. Smart phones can store great amount of informations and are useful for long term monitoring with caution for patient confidentiality. The use of smart phones especially as diagnostic tools is not standardized and results should be carefully considered. Innovative role of smartphone technology and its use in research, education and information sharing makes smart phones a future of ophthalmology and medicine.

Covalent adaptable networks: smart, reconfigurable and responsive network systems.

PubMed

Kloxin, Christopher J; Bowman, Christopher N

2013-09-07

Covalently crosslinked materials, classically referred to as thermosets, represent a broad class of elastic materials that readily retain their shape and molecular architecture through covalent bonds that are ubiquitous throughout the network structure. These materials, in particular in their swollen gel state, have been widely used as stimuli responsive materials with their ability to change volume in response to changes in temperature, pH, or other solvent conditions and have also been used in shape memory applications. However, the existence of a permanent, unalterable shape and structure dictated by the covalently crosslinked structure has dramatically limited their abilities in this and many other areas. These materials are not generally reconfigurable, recyclable, reprocessable, and have limited ability to alter permanently their stress state, topography, topology, or structure. Recently, a new paradigm has been explored in crosslinked polymers - that of covalent adaptable networks (CANs) in which covalently crosslinked networks are formed such that triggerable, reversible chemical structures persist throughout the network. These reversible covalent bonds can be triggered through molecular triggers, light or other incident radiation, or temperature changes. Upon application of this stimulus, rather than causing a temporary shape change, the CAN structure responds by permanently adjusting its structure through either reversible addition/condensation or through reversible bond exchange mechanisms, either of which allow the material to essentially reequilibrate to its new state and condition. Here, we provide a tutorial review on these materials and their responsiveness to applied stimuli. In particular, we review the broad classification of these materials, the nature of the chemical bonds that enable the adaptable structure, how the properties of these materials depend on the reversible structure, and how the application of a stimulus causes these materials to alter their shape, topography, and properties.

Non-destructive X-ray examination of weft knitted wire structures

NASA Astrophysics Data System (ADS)

Obermann, M.; Ellouz, M.; Aumann, S.; Martens, Y.; Bartelt, P.; Klöcker, M.; Kordisch, T.; Ehrmann, A.; Weber, M. O.

2016-07-01

Conductive yarns or wires are often integrated in smart textiles to enable data or energy transmission. In woven fabrics, these conductive parts are fixed at defined positions and thus protected from external loads. Knitted fabrics, however, have relatively loose structures, resulting in higher impacts of possible mechanical forces on the individual yarns. Hence, metallic wires with smaller diameters in particular are prone to break when integrated in knitted fabrics. In a recent project, wires of various materials including copper, silver and nickel with diameters varying between 0.05 mm and 0.23 mm were knitted in combination with textile yarns. Hand flat knitting machines of appropriate gauges were used to produce different structures. On these samples, non-destructive examinations, using an industrial X-ray system Seifert x|cube (225 kV) equipped with a minifocus X-ray tube, were carried out, directly after knitting as well as after different mechanical treatments (tensile, burst, and washing tests). In this way, structural changes of the stitch geometry could be visualized before failure. In this paper, the loop geometries in the knitted fabrics are depicted depending on knitted structures, wire properties and the applied mechanical load. Consequently, it is shown which metallic wires and yarns are most suitable to be integrated into knitted smart textiles.

Crack detection and leakage monitoring on reinforced concrete pipe

NASA Astrophysics Data System (ADS)

Feng, Qian; Kong, Qingzhao; Huo, Linsheng; Song, Gangbing

2015-11-01

Reinforced concrete underground pipelines are some of the most widely used types of structures in water transportation systems. Cracks and leakage are the leading causes of pipeline structural failures which directly results in economic losses and environmental hazards. In this paper, the authors propose a piezoceramic based active sensing approach to detect the cracks and the further leakage of concrete pipelines. Due to the piezoelectric properties, piezoceramic material can be utilized as both the actuator and the sensor in the active sensing approach. The piezoceramic patch, which is sandwiched between protective materials called ‘smart aggregates,’ can be safely embedded into concrete structures. Circumferential and axial cracks were investigated. A wavelet packet-based energy analysis was developed to distinguish the type of crack and determine the further leakage based on different stress wave energy attenuation propagated through the cracks.

A Framework to Develop Persuasive Smart Environments

NASA Astrophysics Data System (ADS)

Lobo, Pedro; Romão, Teresa; Dias, A. Eduardo; Danado, José Carlos

This paper presents a framework for the creation of context-sensitive persuasive applications. The framework allows the authoring of new persuasive smart environments producing the appropriate feedback to the users based on different sensors spread throughout the environment to capture contextual information. Using this framework, we created an application, Smart Bins, aimed at promoting users' behavioural changes regarding the recycling of waste materials. Furthermore, to evaluate the usability of our authoring tool, we performed user tests to analyze if developers could successfully create the Smart Bins application using the framework. A description of the Smart Bins application, as well as the results of the user tests, are also presented in this paper.

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

DOT National Transportation Integrated Search

2011-07-01

In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) : sandwich materials for various transportation construction applications, with particular emphasis : on highway bridge decks in cold regions, were developed and teste...

Anisotropic Nanomechanics of Boron Nitride Nanotubes: Nanostructured "Skin" Effect

NASA Technical Reports Server (NTRS)

Srivastava, Deepak; Menon, Madhu; Cho, KyeongJae

2000-01-01

The stiffness and plasticity of boron nitride nanotubes are investigated using generalized tight-binding molecular dynamics and ab-initio total energy methods. Due to boron-nitride BN bond buckling effects, compressed zigzag BN nanotubes are found to undergo novel anisotropic strain release followed by anisotropic plastic buckling. The strain is preferentially released towards N atoms in the rotated BN bonds. The tubes buckle anisotropically towards only one end when uniaxially compressed from both. A "skin-effect" model of smart nanocomposite materials is proposed which will localize the structural damage towards the 'skin' or surface side of the material.

Occupancy-driven smart register for building energy saving (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chen, Zhangjie; Wang, Ya S.

2017-04-01

The new era in energy-efficiency building is to integrate automatic occupancy detection with automated heating, ventilation and cooling (HVAC), the largest source of building energy consumption. By closing off some air vents, during certain hours of the day, up to 7.5% building energy consumption could be saved. In the past, smart vent has received increasing attention and several products have been developed and introduced to the market for building energy saving. For instance, Ecovent Systems Inc. and Keen Home Inc. have both developed smart vent registers capable of turning the vent on and off through smart phone apps. However, their products do not have on-board occupancy sensors and are therefore open-loop. Their vent control was achieved by simply positioning the vent blade through a motor and a controller without involving any smart actuation. This paper presents an innovative approach for automated vent control and automatic occupancy (human subjects) detection. We devise this approach in a smart register that has polydimethylsiloxane (PDMS) frame with embedded Shape memory alloy (SMA) actuators. SMAs belong to a class of shape memory materials (SMMs), which have the ability to `memorise' or retain their previous form when subjected to certain stimulus such as thermomechanical or magnetic variations. And it can work as actuators and be applied to vent control. Specifically, a Ni-Ti SMA strip will be pre-trained to a circular shape, wrapped with a Ni-Cr resistive wire that is coated with thermally conductive and electrically isolating material. Then, the SMA strip along with an antagonistic SMA strip will be bonded with PZT sensor and thermal sensors, to be inserted into a 3D printed mould which will be filled with silicone rubber materials. In the end, a demoulding process yields a fully integrated blade of the smart register. Several blades are installed together to form the smart register. The PZT sensors can feedback the shape of the actuator for precise shape and air flow control. The performance and the specification of the smart registers will be characterized experimentally. Its capacity of regulating airflow, forming air curtain will be demonstrated.

Fiber Optic Sensor Components and Systems for Smart Materials and Structures

NASA Technical Reports Server (NTRS)

Lyons, R.

1999-01-01

The general objective of the funded research effort has been the development of discrete and distributed fiber sensors and fiber optic centered opto-electronic networks for the intelligent monitoring of phenomena in various aerospace structures related to NASA Marshall specific applications. In particular, we have proposed and have been developing technologies that we believe to be readily transferrable and which involve new fabrication techniques. The associated sensors developed can be incorporated into the matrix or on the surfaces of structures for the purpose of sensing stress, strain, temperature-both low and high, pressure field variations, phase changes, and the presence of various chemical constituents.

Control Demonstration of a Thin Deformable In-Plane Actuated Mirror

DTIC Science & Technology

2006-03-01

where a four-quadrant electrode grid sitting behind a pre-shaped membrane mirror uses electrostatic forces to deform the surface. Any manufacturing...to receive the Wavescope data due to its MATLAB and Simulink capa- bilities. The dSPACE computer system is stocked with a UART (Universal Asynchronous...cations,” SPIE Smart Structures and Materials Symposium, EAPAD Conference, Vol. 5051-45 (2003). 6. Bennet, H. E. and others, . “Development of

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

DOT National Transportation Integrated Search

2011-07-01

In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) sandwich materials for various transportation construction applications, with particular emphasis on highway bridge decks in cold regions, were developed and tested. T...

Biopolymer-based strategies in the design of smart medical devices and artificial organs.

PubMed

Altomare, Lina; Bonetti, Lorenzo; Campiglio, Chiara E; De Nardo, Luigi; Draghi, Lorenza; Tana, Francesca; Farè, Silvia

2018-06-01

Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.

EDITORIAL: Welcome to the 2013 volume Welcome to the 2013 volume

NASA Astrophysics Data System (ADS)

Garcia, Ephrahim

2013-01-01

Welcome to 2013; another great year for technology in our journal, Smart Materials and Structures (SMS). Last year, SMS grew by some 11% while maintaining a high Impact Factor above 2 and a rejection rate of 60%. The Editorial Board and I are pleased with this outcome, as it's indicative of the relevance and vibrancy of SMS to our research community. SMS continues to have a leading role within our community of researchers in the field of smart materials and smart systems technology. As always the quality of SMS is something that the Editorial Board takes very seriously. I have instructed the Editorial Board and our reviewers to scrutinize manuscripts, not only for originality and contributions to the field of smart materials and structures, but to consider the potential impact on the technology. In addition, we are doing more to architect the content of our issues, creating a conduit for exciting developments, developing review topics, and publishing focus issues that cover current technological trends. We would like to promote SMS as a medium to accelerate the promotion of the latest technology. Toward this end, SMS has instituted the Fast Track Communication (FTC). FTCs are short, urgent announcements reporting new and timely developments in the field. They benefit from extra post-publication promotion and accelerated peer review. SMS also has a strong program of topical review articles. Many of us are professors, involved with the training of new researchers to our field, and the value of review articles to education and training cannot be overstated. Such articles allow a reader to 'get up to speed' quickly in a new area, whether they be new graduate students or seasoned technologists deciphering what smart materials has to offer a particular application. Review topics are considered by me and the Editorial Board for content. If approved, SMS will commission a writer to prepare the article for which they will receive a fee in appreciation for the service they have done the community. In 2012, we published 'A review on structural enhancement and repair using piezoelectric materials and shape memory alloys' by Quan Wang and Nan Wu, University of Manitoba; 'A review of stimuli-responsive polymers for smart textile applications' by Jinlian Hu et al, The Hong Kong Polytechnic University and Southern University, USA; and 'Hair flow sensors: from bioinspiration to bio-mimicking—a review' by Junliang Tao et al, Case Western Reserve University. The third approach we take to serve our readership is the development of special issues. Special issues contain a selected collection of papers from specific conferences of particular importance to our readers. Additionally, we publish focus issues, which consist of a collection of invited research papers to provide a timely snap shot of the state of the art of a particularly relevant topic. This, the first issue of 2013, features a focus issue called 'Bioinspired smart materials and systems'. My co-Editors for this were Dr Rashi Tiwari of Dow Chemical Company and Dr Matthew Bryant of Cornell University. Nature is the ultimate builder of machines. The simplest of organisms utilize atomic scale engineering to build systems from fundamental chemistry into tissue with functional gradation to alter properties, integrated with electrical, chemical and mechanical capabilities. These living systems scavenge energy from their environs, are self-programming and adaptive, are capable of self-replication and evolve over generations perpetuating their species over time. As engineers and materials scientists, our greatest achievements to date are at best primitive by comparison. Yet, as a source of inspiration, there are lessons to be learned from which we can gather insight. While often beautiful to observe and mimic superficially, much more substantive technological gains can be achieved by developing an understanding of the complex ways living organisms interact with and manipulate their environments. It is at this distinction between bio-mimicry and bioinspiration where engineers can learn and gain the most from nature. Taking advantage of bioinspiration requires us to utilize models, design techniques, transducers, and structures beyond what conventional, uni-disciplinary engineering practice has offered. The unique properties of smart materials can allow us to create multirole sensing, actuation, energy conversion and structural elements that enable these bioinspired systems. In this focus issue, we are pleased to present a broad collection of original research papers that embody the concept of bioinspired smart materials and systems. The topics of these papers span from bioinspired locomotion architectures such as in micro-robots, to muscle-inspired actuation technologies, and to sensor designs motivated by the functionality of sensory organs of fish and marine mammals. Others offer designs for energy harvesting mechanisms based on the structure of hair bundles, damage monitoring systems that mimic the human nervous system, filtration systems that selectively capture and transport water pollutants and material surface properties akin to the superhydrophobic lotus leaf. It is our hope that the broad range of topics and applications under consideration reflect the diversity of nature and the myriad of technical approaches that can be derived by considering biological design inspiration. We hope our readers enjoy this collection. Finally, I would like to thank my wonderful Editorial Board for their great work in ensuring and constantly improving the quality of SMS. The Board serves not only to advise the Editor-in-Chief but actively participates in the paper review process as Associate Editors, overseeing and reviewing articles as well. We welcome Professor Yanju Liu (Harbin Institute of Technology, China) and Professor Daihua Wang (Chongqing University, China) who have recently joined the Board. We also acknowledge the hard work and dedicated service of Professor Derek Abbott, Professor Alison Flatau, Professor Jinsong Leng and Professor Yuji Matsuzaki who have retired from the Board. Professor Matsuzaki worked on the journal for almost two decades. Associate Editors Professor G Akhras, Royal Military College of Canada, Ontario, Canada Professor C Boller, University of Saarland, Saarbrücken, Germany; Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren, Dresden, Germany Professor Cagnol, École Centrale Paris, France Professor G Carman, University of California-Los Angeles, USA Professor S-B Choi, Inha University, Incheon, Korea Professor S H Choi, NASA Langley Research Center, Hampton, VA, USA Professor A Del Grosso, Università degli Studi di Genova, Italy Professor D Erickson, Cornell University, Ithaca, NY, USA Professor U Gabbert, Universität Magdeburg, Germany Professor A Güemes, Universidad Politecnica de Madrid, Spain Professor S Gopalakrishnan, Indian Institute of Science, Bangalore, India Professor J Kim, Inha University, Incheon, Korea Professor K J Kim, University of Nevada, Reno, USA Professor S J Kim, Seoul National University, Korea Professor D Lagoudas, Texas A&M University, College Station, USA Professor R Lammering, Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg, Hamburg, Germany Professor C K Lee, National Taiwan University, Taiwan Professor W Li, University of Wollongong, Australia Professor W H Liao, Chinese University of Hong Kong, China Professor Y Liu, Harbin Institute of Technology, China Professor C S Lynch, University of California-Los Angeles, USA Professor S Masri, University of Southern California, Los Angeles, USA Professor W M Ostachowicz, Polish Academy of Sciences, Gdansk, Poland Professor K Peters, North Carolina State University, Raleigh, USA Professor M Shahinpoor, University of New Mexico, Albuquerque, USA Professor H Sodano, Arizona State University, Tempe, USA Professor G Song, University of Houston, TX, USA Professor W J Staszewski, AGH University of Science and Technology, Kraków, Poland Professor N Takeda, University of Tokyo, Japan Professor D-H Wang, Chongqing University, China Professor Q Wang, University of Manitoba, Canada Professor N M Wereley, University of Maryland, College Park, USA Professor W J Wu, National Taiwan University, Taiwan We will continue to engage our community of researchers and encourage the development of new smart materials and structural systems and devices that rely on new and exciting, controllable electro-active elements.

Bioresponsive materials

NASA Astrophysics Data System (ADS)

Lu, Yue; Aimetti, Alex A.; Langer, Robert; Gu, Zhen

2017-01-01

'Smart' bioresponsive materials that are sensitive to biological signals or to pathological abnormalities, and interact with or are actuated by them, are appealing therapeutic platforms for the development of next-generation precision medications. Armed with a better understanding of various biologically responsive mechanisms, researchers have made innovations in the areas of materials chemistry, biomolecular engineering, pharmaceutical science, and micro- and nanofabrication to develop bioresponsive materials for a range of applications, including controlled drug delivery, diagnostics, tissue engineering and biomedical devices. This Review highlights recent advances in the design of smart materials capable of responding to the physiological environment, to biomarkers and to biological particulates. Key design principles, challenges and future directions, including clinical translation, of bioresponsive materials are also discussed.

Chromogenic switchable glazing: Towards the development of the smart window

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lampert, C.M.

1995-06-01

The science and technology of chromogenic materials for switchable glazings in building applications is discussed. These glazings can be used for dynamic control of solar and visible energy. Currently many researchers and engineers are involved with the development of products in this field. A summary of activities in Japan, Europe, Australia, USA and Canada is made. The activities of the International Energy Agency are included. Both non-electrically activated and electrically activated glazings are discussed. Technologies covered in the first category are photochromics, and thermochromics and thermotropics. A discussion of electrically activated chromogenic glazings includes dispersed liquid crystals, dispersed particles andmore » electrochromics. A selection of device structures and performance characteristics are compared. A discussion of transparent conductors is presented. Technical issues concerning large-area development of smart windows are discussed.« less

Polarization holograms in a bifunctional amorphous polymer exhibiting equal values of photoinduced linear and circular birefringences.

PubMed

Provenzano, Clementina; Pagliusi, Pasquale; Cipparrone, Gabriella; Royes, Jorge; Piñol, Milagros; Oriol, Luis

2014-10-09

Light-controlled molecular alignment is a flexible and useful strategy introducing novelty in the fields of mechanics, self-organized structuring, mass transport, optics, and photonics and addressing the development of smart optical devices. Azobenzene-containing polymers are well-known photocontrollable materials with large and reversible photoinduced optical anisotropies. The vectorial holography applied to these materials enables peculiar optical devices whose properties strongly depend on the relative values of the photoinduced birefringences. Here is reported a polarization holographic recording based on the interference of two waves with orthogonal linear polarization on a bifunctional amorphous polymer that, exceptionally, exhibits equal values of linear and circular birefringence. The peculiar photoresponse of the material coupled with the holographic technique demonstrates an optical device capable of decomposing the light into a set of orthogonally polarized linear components. The holographic structures are theoretically described by the Jones matrices method and experimentally investigated.

Poling of PVDF matrix composites for integrated structural load sensing

NASA Astrophysics Data System (ADS)

Haghiashtiani, Ghazaleh; Greminger, Michael A.; Zhao, Ping

2014-03-01

The purpose of this study is to create and evaluate a smart composite structure that can be used for integrated load sensing and structural health monitoring. In this structure, PVDF films are used as the matrix material instead of epoxy resin or other thermoplastics. The reinforcements are two layers of carbon fiber with one layer of Kevlar separating them. Due to the electrical conductivity properties of carbon fiber and the dielectric effect of Kevlar, the structure acts as a capacitor. Furthermore, the piezoelectric properties of the PVDF matrix can be used to monitor the response of the structure under applied loads. In order to exploit the piezoelectric properties of PVDF, the PVDF material must be polarized to align the dipole moments of its crystalline structure. The optimal condition for poling the structure was found by performing a 23 factorial design of experiment (DoE). The factors that were studied in DoE were temperature, voltage, and duration of poling. Finally, the response of the poled structure was monitored by exposing the samples to an applied load.

SMART Structures User's Guide - Version 3.0

NASA Technical Reports Server (NTRS)

Spangler, Jan L.

1996-01-01

Version 3.0 of the Solid Modeling Aerospace Research Tool (SMART Structures) is used to generate structural models for conceptual and preliminary-level aerospace designs. Features include the generation of structural elements for wings and fuselages, the integration of wing and fuselage structural assemblies, and the integration of fuselage and tail structural assemblies. The highly interactive nature of this software allows the structural engineer to move quickly from a geometry that defines a vehicle's external shape to one that has both external components and internal components which may include ribs, spars, longerons, variable depth ringframes, a floor, a keel, and fuel tanks. The geometry that is output is consistent with FEA requirements and includes integrated wing and empennage carry-through and frame attachments. This report provides a comprehensive description of SMART Structures and how to use it.

A twice-as-smart synthetic G-quartet: PyroTASQ is both a smart quadruplex ligand and a smart fluorescent probe.

PubMed

Laguerre, Aurélien; Stefan, Loic; Larrouy, Manuel; Genest, David; Novotna, Jana; Pirrotta, Marc; Monchaud, David

2014-09-03

Recent and unambiguous evidences of the formation of DNA and RNA G-quadruplexes in cells has provided solid support for these structures to be considered as valuable targets in oncology. Beyond this, they have lent further credence to the anticancer strategies relying on small molecules that selectively target these higher-order DNA/RNA architectures, referred to as G-quadruplex ligands. They have also shed bright light on the necessity of designing multitasking ligands, displaying not only enticing quadruplex interacting properties (affinity, structural selectivity) but also additional features that make them usable for detecting quadruplexes in living cells, notably for determining whether, when, and where these structures fold and unfold during the cell cycle and also for better assessing the consequences of their stabilization by external agents. Herein, we report a brand new design of such multitasking ligands, whose structure experiences a quadruplex-promoted conformational switch that triggers not only its quadruplex affinity (i.e., smart ligands, which display high affinity and selectivity for DNA/RNA quadruplexes) but also its fluorescence (i.e., smart probes, which behave as selective light-up fluorescent reporters on the basis of a fluorogenic electron redistribution). The first prototype of such multifunctional ligands, termed PyroTASQ, represents a brand new generation of quadruplex ligands that can be referred to as "twice-as-smart" quadruplex ligands.

A periodic piezoelectric smart structure with the integrated passive/active vibration-reduction performances

NASA Astrophysics Data System (ADS)

Wang, Yuxi; Niu, Shengkai; Hu, Yuantai

2017-06-01

The paper proposes a new piezoelectric smart structure with the integrated passive/active vibration-reduction performances, which is made of a series of periodic structural units. Every structural unit is made of two layers, one is an array of piezoelectric bimorphs (PBs) and one is an array of metal beams (MBs), both are connected as a whole by a metal plate. Analyses show that such a periodic smart structure possesses two aspects of vibration-reduction performance: one comes from its phonon crystal characteristics which can isolate those vibrations with the driving frequency inside the band gap(s). The other one comes from the electromechanical conversion of bent PBs, which is actively aimed at those vibrations with the driving frequency outside the band gap(s). By adjusting external inductance, the equivalent circuit of the proposed structure can be forced into parallel resonance such that most of the vibration energy is converted into electrical energy for dissipation by a resistance. Thus, an external circuit under the parallel resonance state is equivalent to a strong damping to the interrelated vibrating structure, which is just the action mechanism of the active vibration reduction performance of the proposed smart structure.

New Materials for Structural Composites and Protective Coatings

NASA Technical Reports Server (NTRS)

2008-01-01

The objective of this Phase I project was to create novel conductive materials that are lightweight and strong enough for multiple ground support equipment and Exploration applications. The long-term goal is to combine these materials within specially designed devices to create composites or coatings with diagnostic capabilities, increased strength, and tunable properties such as transparency, electroluminescence, and fire resistance. One such technology application is a smart windows system. In such a system, the transmission of light through a window is controlled by electrical power. In the future, these materials may also be able to absorb sunlight and convert it into electrical energy to produce light, thereby creating a self-sufficient lighting system. This experiment, conducted in collaboration with the Georgia Institute of Technology, demonstrated enhancements in fabricating fiber materials from carbon nanotubes (CNT). These nanotubes were grown as forests in an ultra-high-purity chemical vapor deposition (CVD) furnace and then drawn, using novel processing techniques, into fibers and yarns that would be turned into filaments. This work was submitted to the Journal of Advanced Functional Materials. The CNT fibers were initially tested as filament materials at atmospheric pressure; however, even under high current loads, the filaments produced only random sparking. The CNT fibers were also converted into transparent, hydrophobic, and conductive sheets. Filament testing at low vacuum pressures is in progress, and the technology will be enhanced in 2008. As initial proof of the smart-windows application concept, the use of CNT sheets as composites/ protective coatings was demonstrated in collaboration with Nanocomp Technologies of Concord, New Hampshire.

Molecular Motions in Functional Self-Assembled Nanostructures

PubMed Central

Dhotel, Alexandre; Chen, Ziguang; Delbreilh, Laurent; Youssef, Boulos; Saiter, Jean-Marc; Tan, Li

2013-01-01

The construction of “smart” materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces and smart nanomaterials. Structural flexibility of these materials is known to be conferred by weak intermolecular forces involved in self-assembly strategies. However, some fundamental mechanisms responsible for conformational lability remain unexplored. Furthermore, the role played by stronger bonds, such as coordination, ionic and covalent bonding, is sometimes neglected while they can be employed readily to produce mechanically robust but also chemically reversible structures. In this review, recent applications of structural flexibility and molecular motions in self-assembled nanostructures are discussed. Special focus is given to advanced materials exhibiting significant performance changes after an external stimulus is applied, such as light exposure, pH variation, heat treatment or electromagnetic field. The crucial role played by strong intra- and weak intermolecular interactions on structural lability and responsiveness is highlighted. PMID:23348927

Topological mechanics: from metamaterials to active matter

NASA Astrophysics Data System (ADS)

Vitelli, Vincenzo

2015-03-01

Mechanical metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable acoustic response, which originate in the geometry of their unit cell. At the heart of such unusual behavior is often a mechanism: a motion that does not significantly stretch or compress the links between constituent elements. When activated by motors or external fields, these soft motions become the building blocks of robots and smart materials. In this talk, we discuss topological mechanisms that possess two key properties: (i) their existence cannot be traced to a local imbalance between degrees of freedom and constraints (ii) they are robust against a wide range of structural deformations or changes in material parameters. The continuum elasticity of these mechanical structures is captured by non-linear field theories with a topological boundary term similar to topological insulators and quantum Hall systems. We present several applications of these concepts to the design and experimental realization of 2D and 3D topological structures based on linkages, origami, buckling meta-materials and lastly active media that break time-reversal symmetry.

Determination of Optimal Heat-Storage Thickness of Layer for “Smart Wall” by Methods of Nonlinear Heat Conduction Equations for Phase-transition Materials

NASA Astrophysics Data System (ADS)

Pospelova, I.

2017-11-01

The article suggests an original way of keeping heat load and its compensation for a microclimate system by proposing the “Smart Wall”. The construction consists of specially combined composite materials including phase-transition materials. The method for determination of the layer thickness is proposed for a certain accumulation time. Varying the thickness and composition of the layer it is possible to achieve a low amount of the thermal conductivity coefficient and to obtain various functional characteristics of fences.

"Chemical transformers" from nanoparticle ensembles operated with logic.

PubMed

Motornov, Mikhail; Zhou, Jian; Pita, Marcos; Gopishetty, Venkateshwarlu; Tokarev, Ihor; Katz, Evgeny; Minko, Sergiy

2008-09-01

The pH-responsive nanoparticles were coupled with information-processing enzyme-based systems to yield "smart" signal-responsive hybrid systems with built-in Boolean logic. The enzyme systems performed AND/OR logic operations, transducing biochemical input signals into reversible structural changes (signal-directed self-assembly) of the nanoparticle assemblies, thus resulting in the processing and amplification of the biochemical signals. The hybrid system mimics biological systems in effective processing of complex biochemical information, resulting in reversible changes of the self-assembled structures of the nanoparticles. The bioinspired approach to the nanostructured morphing materials could be used in future self-assembled molecular robotic systems.

Dynamic characterization, monitoring and control of rotating flexible beam-mass structures via piezo-embedded techniques

NASA Technical Reports Server (NTRS)

Lai, Steven H.-Y.

1992-01-01

A variational principle and a finite element discretization technique were used to derive the dynamic equations for a high speed rotating flexible beam-mass system embedded with piezo-electric materials. The dynamic equation thus obtained allows the development of finite element models which accommodate both the original structural element and the piezoelectric element. The solutions of finite element models provide system dynamics needed to design a sensing system. The characterization of gyroscopic effect and damping capacity of smart rotating devices are addressed. Several simulation examples are presented to validate the analytical solution.

Aeroelastic analysis of an adaptive trailing edge with a smart elastic skin

NASA Astrophysics Data System (ADS)

Arena, Maurizio; Pecora, Rosario; Amoroso, Francesco; Noviello, Maria Chiara; Rea, Francesco; Concilio, Antonio

2017-09-01

Nowadays, the design choices of the new generation aircraft are moving towards the research and development of innovative technologies, aimed at improving performance as well as to minimize the environmental impact. In the current "greening" context, the morphing structures represent a very attractive answer to such requirements: both aerodynamic and structural advantages are ensured in several flight conditions, safeguarding the fuel consumption at the same time. An aeronautical intelligent system is therefore the outcome of combining complex smart materials and structures, assuring the best functionality level in the flight envelope. The Adaptive Trailing Edge Device (ATED) is a sub-project inside SARISTU (Smart Intelligent Aircraft Structures), an L2 level project of the 7th EU Framework programme coordinated by Airbus, aimed at developing technologies for realizing a morphing wing extremity addressed to improve the general aircraft performance and to reduce the fuel burning up to 5%. This specific study, divided into design, manufacturing and testing phases, involved universities, research centers and leading industries of the European consortium. The paper deals with the aeroelastic impact assessment of a full-scale morphing wing trailing edge on a Large Aeroplanes category aircraft. The FE (Finite Element) model of the technology demonstrator, located in the aileron region and manufactured within the project, was referenced to for the extrapolation of the structural properties of the whole adaptive trailing edge device placed in its actual location in the outer wing. The input FE models were processed within MSC-Nastran® environment to estimate stiffness and inertial distributions suitable to construct the aeroelastic stick-beam mock-up of the reference structure. Afterwards, a flutter analysis in simulated operative condition, have been carried out by means of Sandy®, an in-house code, according to meet the safety requirements imposed by the applicable aviation regulations (paragraph 25.629, parts (a) and (b)-(1)).

Functional Polymer Opals and Porous Materials by Shear-Induced Assembly of Tailor-Made Particles.

PubMed

Gallei, Markus

2018-02-01

Photonic band-gap materials attract enormous attention as potential candidates for a steadily increasing variety of applications. Based on the preparation of easily scalable monodisperse colloids, such optically attractive photonic materials can be prepared by an inexpensive and convenient bottom-up process. Artificial polymer opals can be prepared by shear-induced assembly of core/shell particles, yielding reversibly stretch-tunable materials with intriguing structural colors. This feature article highlights recent developments of core/shell particle design and shear-induced opal formation with focus on the combination of hard and soft materials as well as crosslinking strategies. Structure formation of opal materials relies on both the tailored core/shell architecture and the parameters for polymer processing. The emphasis of this feature article is on elucidating the particle design and incorporation of addressable moieties, i.e., stimuli-responsive polymers as well as elaborated crosslinking strategies for the preparation of smart (inverse) opal films, inorganic/organic opals, and ceramic precursors by shear-induced ordering. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Experimental Study on Static and Dynamic Strain Sensitivity of Embeddable Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures.

PubMed

Meoni, Andrea; D'Alessandro, Antonella; Downey, Austin; García-Macías, Enrique; Rallini, Marco; Materazzi, A Luigi; Torre, Luigi; Laflamme, Simon; Castro-Triguero, Rafael; Ubertini, Filippo

2018-03-09

The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix mterials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNT contents. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both quasi-static and sine-sweep dynamic uni-axial compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications.

Structural health monitoring using smart optical fiber sensors

NASA Astrophysics Data System (ADS)

Davies, Heddwyn; Everall, Lorna A.; Gallon, Andrew M.

2001-04-01

This paper describes the potential of a smart monitoring system, incorporating optical fiber sensing techniques, to provide important structural information to designers and users alike. This technology has application in all areas including aerospace, civil, maritime and automotive engineering. In order to demonstrate the capability of the sensing system it has been installed in a 35 m free-standing carbon fiber yacht mast, where a complete optical network of strain and temperature sensors were embedded into a composite mast and boom during lay-up. The system was able to monitor the behavior of the composite rig through a range of handling conditions and the resulting strain information could be used by engineers to improve the structural design process. The optical strain sensor system comprises of three main components: the sensor network, the opto-electronic data acquisition unit (OFSSS) and the external PC which acts as a data log and display. Embedded fiber optic sensors have wide ranging application for structural load monitoring. Due to their small size, optical fiber sensors can be readily embedded into composite materials. Other advantages include their immediate multiplexing capability and immunity to electromagnetic interference. The capability of this system has been demonstrated within the maritime environment, but can be adapted for any application.

An Experimental Study on Static and Dynamic Strain Sensitivity of Embeddable Smart Concrete Sensors Doped with Carbon Nanotubes for SHM of Large Structures

PubMed Central

Meoni, Andrea; D’Alessandro, Antonella; García-Macías, Enrique; Rallini, Marco; Materazzi, A. Luigi; Torre, Luigi; Laflamme, Simon; Castro-Triguero, Rafael

2018-01-01

The availability of new self-sensing cement-based strain sensors allows the development of dense sensor networks for Structural Health Monitoring (SHM) of reinforced concrete structures. These sensors are fabricated by doping cement-matrix mterials with conductive fillers, such as Multi Walled Carbon Nanotubes (MWCNTs), and can be embedded into structural elements made of reinforced concrete prior to casting. The strain sensing principle is based on the multifunctional composites outputting a measurable change in their electrical properties when subjected to a deformation. Previous work by the authors was devoted to material fabrication, modeling and applications in SHM. In this paper, we investigate the behavior of several sensors fabricated with and without aggregates and with different MWCNT contents. The strain sensitivity of the sensors, in terms of fractional change in electrical resistivity for unit strain, as well as their linearity are investigated through experimental testing under both quasi-static and sine-sweep dynamic uni-axial compressive loadings. Moreover, the responses of the sensors when subjected to destructive compressive tests are evaluated. Overall, the presented results contribute to improving the scientific knowledge on the behavior of smart concrete sensors and to furthering their understanding for SHM applications. PMID:29522498

Numerical simulation of actuation behavior of active fiber composites in helicopter rotor blade application

NASA Astrophysics Data System (ADS)

Paik, Seung Hoon; Kim, Ji Yeon; Shin, Sang Joon; Kim, Seung Jo

2004-07-01

Smart structures incorporating active materials have been designed and analyzed to improve aerospace vehicle performance and its vibration/noise characteristics. Helicopter integral blade actuation is one example of those efforts using embedded anisotropic piezoelectric actuators. To design and analyze such integrally-actuated blades, beam approach based on homogenization methodology has been traditionally used. Using this approach, the global behavior of the structures is predicted in an averaged sense. However, this approach has intrinsic limitations in describing the local behaviors in the level of the constituents. For example, the failure analysis of the individual active fibers requires the knowledge of the local behaviors. Microscopic approach for the analysis of integrally-actuated structures is established in this paper. Piezoelectric fibers and matrices are modeled individually and finite element method using three-dimensional solid elements is adopted. Due to huge size of the resulting finite element meshes, high performance computing technology is required in its solution process. The present methodology is quoted as Direct Numerical Simulation (DNS) of the smart structure. As an initial validation effort, present analytical results are correlated with the experiments from a small-scaled integrally-actuated blade, Active Twist Rotor (ATR). Through DNS, local stress distribution around the interface of fiber and matrix can be analyzed.

Fiber Bragg Grating Sensors toward Structural Health Monitoring in Composite Materials: Challenges and Solutions

PubMed Central

Kinet, Damien; Mégret, Patrice; Goossen, Keith W.; Qiu, Liang; Heider, Dirk; Caucheteur, Christophe

2014-01-01

Nowadays, smart composite materials embed miniaturized sensors for structural health monitoring (SHM) in order to mitigate the risk of failure due to an overload or to unwanted inhomogeneity resulting from the fabrication process. Optical fiber sensors, and more particularly fiber Bragg grating (FBG) sensors, outperform traditional sensor technologies, as they are lightweight, small in size and offer convenient multiplexing capabilities with remote operation. They have thus been extensively associated to composite materials to study their behavior for further SHM purposes. This paper reviews the main challenges arising from the use of FBGs in composite materials. The focus will be made on issues related to temperature-strain discrimination, demodulation of the amplitude spectrum during and after the curing process as well as connection between the embedded optical fibers and the surroundings. The main strategies developed in each of these three topics will be summarized and compared, demonstrating the large progress that has been made in this field in the past few years. PMID:24763215

Piezoceramic devices and artificial intelligence time varying concepts in smart structures

NASA Technical Reports Server (NTRS)

Hanagud, S.; Calise, A. J.; Glass, B. J.

1990-01-01

The problem of development of smart structures and their vibration control by the use of piezoceramic sensors and actuators have been discussed. In particular, these structures are assumed to have time varying model form and parameters. The model form may change significantly and suddenly. Combined identification of the model from parameters of these structures and model adaptive control of these structures are discussed in this paper.

Multiple Routes to Smart Nanostructured Materials from Diatom Microalgae: A Chemical Perspective.

PubMed

Ragni, Roberta; Cicco, Stefania R; Vona, Danilo; Farinola, Gianluca M

2018-05-01

Diatoms are unicellular photosynthetic microalgae, ubiquitously diffused in both marine and freshwater environments, which exist worldwide with more than 100 000 species, each with different morphologies and dimensions, but typically ranging from 10 to 200 µm. A special feature of diatoms is their production of siliceous micro- to nanoporous cell walls, the frustules, whose hierarchical organization of silica layers produces extraordinarily intricate pore patterns. Due to the high surface area, mechanical resistance, unique optical features, and biocompatibility, a number of applications of diatom frustules have been investigated in photonics, sensing, optoelectronics, biomedicine, and energy conversion and storage. Current progress in diatom-based nanotechnology relies primarily on the availability of various strategies to isolate frustules, retaining their morphological features, and modify their chemical composition for applications that are not restricted to those of the bare biosilica produced by diatoms. Chemical or biological methods that decorate, integrate, convert, or mimic diatoms' biosilica shells while preserving their structural features represent powerful tools in developing scalable, low-cost routes to a wide variety of nanostructured smart materials. Here, the different approaches to chemical modification as the basis for the description of applications relating to the different materials thus obtained are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methodology and technological aspects of the flexible substrate preparation for ink-jet printing technology

NASA Astrophysics Data System (ADS)

Tarapata, Grzegorz; Marzecki, Michał

2013-10-01

The ink-jet printing technology becomes especially promising for wide volume of production of cheap sensors, consumable electronics and other dedicated applications of everyday life like smart packaging, smart textiles, smart labels, etc. To achieve this goal new materials compatible with ink-jet printing should be developed. Currently on the market there is a growing number of inks with different properties, but their use requires many tests related to its printability and their interaction with other materials. The paper presents technological problems that are encountered by people associated with fabrication of various devices with using of inkjet printing techniques. Results presented in the paper show the influence of surface preparation techniques on the quality of achieved shapes, the impact of other materials already deposited and the impact of another external factors. During carried out experiments the printer Dimatix DMP 2831 and several inks base on nanosilver or dielectric UV curable was used.

Engineering Amorphous Systems, Using Global-to-Local Compilation

NASA Astrophysics Data System (ADS)

Nagpal, Radhika

Emerging technologies are making it possible to assemble systems that incorporate myriad of information-processing units at almost no cost: smart materials, selfassembling structures, vast sensor networks, pervasive computing. How does one engineer robust and prespecified global behavior from the local interactions of immense numbers of unreliable parts? We discuss organizing principles and programming methodologies that have emerged from Amorphous Computing research, that allow us to compile a specification of global behavior into a robust program for local behavior.

Experimental characterization of a bi-dimensional array of negative capacitance piezo-patches for vibroacoustic control

NASA Astrophysics Data System (ADS)

Tateo, F.; Collet, M.; Ouisse, M.; Ichchou, M. N.; Cunefare, K. A.

2013-04-01

A recent technological revolution in the fields of integrated MEMS has finally rendered possible the mechanical integration of active smart materials, electronics and power supply systems for the next generation of smart composite structures. Using a bi-dimensional array of electromechanical transducers, composed by piezo-patches connected to a synthetic negative capacitance, it is possible to modify the dynamics of the underlying structure. In this study, we present an application of the Floquet-Bloch theorem for vibroacoustic power flow optimization, by means of distributed shunted piezoelectric material. In the context of periodically distributed damped 2D mechanical systems, this numerical approach allows one to compute the multi-modal waves dispersion curves into the entire first Brillouin zone. This approach also permits optimization of the piezoelectric shunting electrical impedance, which controls energy diffusion into the proposed semi-active distributed set of cells. Furthermore, we present experimental evidence that proves the effectiveness of the proposed control method. The experiment requires a rectangular metallic plate equipped with seventy-five piezo-patches, controlled independently by electronic circuits. More specifically, the out-of-plane displacements and the averaged kinetic energy of the controlled plate are compared in two different cases (open-circuit and controlled circuit). The resulting data clearly show how this proposed technique is able to damp and selectively reflect the incident waves.

Study on the fabricating process monitoring of thermoplastic based materials packaged OFBG and their sensing properties

NASA Astrophysics Data System (ADS)

Wang, Chuan; Zhou, Zhi; Zhang, Zhichun; Ou, Jinping

2007-04-01

As common materials or engineering materials, thermoplastic resin based materials can be used not only directly fabricating products but also FRTP(fiber reinforced thermoplastic polymer) materials for other uses. As one kind of FRTP material, GFRPP(glass fiber reinforced polypropylene) has lots of merits, such as: light weight, high strength, high tenacity, high elongation percentage, good durability, reshaping character and no environmental pollution characters. And they also can be conveniently formed hoop rebar in civil engineering. While a new kind of GFRPP-OFBG smart rod which combined GFRPP and OFBG together can be used as not only structure materials but also sensing materials. Meanwhile, PP packaged OFBG strain sensor can be expected for its low modulus, good sensitivity and good durability. Furthermore, it can be used for large strain measuring. In this paper, we have successfully fabricated a new kind of GFRPP-OFBG(Glass Fiber Reinforced Polypropylene-Optic Fiber Bragg Grating) rod by our own thermoplastic pultrusion production line and a new kind of PP packaged OFBG strain sensor by extruding techniques. And we monitored the inner strain and temperature changes with tow OFBG simultaneously of the fabricating process. The results show that: OFBG can truly reflect the strain and temperature changes in both the GFRPP rod and the PP packaged OFBG, these are very useful to modify our processing parameters. And we also find that because of the shrinkage of PP, this new kind of PP packaged OFBG have -13000μɛ storage, and the strain sensing performance is still very well, so which can be used for large strain measuring. Besides these, GFRPP-OFBG smart rod has good sensing performance in strain sensing just like that of FRSP-OFBG rod, the strain sensitivity coefficient is about1.19pm/μɛ. Besides these, the surface of GFRPP-OFBG rods can be handled just as steel bars and also can be bended and reshaped. These are all very useful and very important for the use of FRP materials in civil engineering structures.

Literature Review and Assessment of Nanotechnology for Sensing of Timber Transportation Structures Final Report

Treesearch

Terry Wipf; Brent M. Phares; Micheal Ritter

2012-01-01

Recently efforts have been put toward the development of civil structures that have embedded sensors and on-board data processing capabilities, typically termed “smart structures.” The fusion of these smart technologies into infrastructures is intended to give bridge owners/managers better and more timely information on how structures are behaving and when they need...

Smart surgical tool

NASA Astrophysics Data System (ADS)

Huang, Huan; Yang, Lih-Mei; Bai, Shuang; Liu, Jian

2015-02-01

A laser-induced breakdown spectroscopy (LIBS) guided smart surgical tool using a femtosecond fiber laser is developed. This system provides real-time material identification by processing and analyzing the peak intensity and ratio of atomic emissions of LIBS signals. Algorithms to identify emissions of different tissues and metals are developed and implemented into the real-time control system. This system provides a powerful smart surgical tool for precise robotic microsurgery applications with real-time feedback and control.

Deformation behavior of carbon-fiber reinforced shape-memory-polymer composites used for deployable structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lan, Xin; Liu, Liwu; Li, Fengfeng; Pan, Chengtong; Liu, Yanju; Leng, Jinsong

2017-04-01

Shape memory polymers (SMPs) are a new type of smart material, they perform large reversible deformation with a certain external stimulus (e.g., heat and electricity). The properties (e.g., stiffness, strength and other mechanically static or quasi-static load-bearing capacity) are primarily considered for conventional resin-based composite materials which are mainly used for structural materials. By contrast, the mechanical actuating performance with finite deformation is considered for the shape memory polymers and their composites which can be used for both structural materials and functional materials. For shape memory polymers and their composites, the performance of active deformation is expected to further promote the development in smart active deformation structures, such as deployable space structures and morphing wing aircraft. The shape memory polymer composites (SMPCs) are also one type of High Strain Composite (HSC). The space deployable structures based on carbon fiber reinforced shape memory polymer composites (SMPCs) show great prospects. Considering the problems that SMPCs are difficult to meet the practical applications in space deployable structures in the recent ten years, this paper aims to research the mechanics of deformation, actuation and failure of SMPCs. In the overall view of the shape memory polymer material's nonlinearity (nonlinearity and stress softening in the process of pre-deformation and recovery, relaxation in storage process, irreversible deformation), by the multiple verifications among theory, finite element and experiments, one obtains the deformation and actuation mechanism for the process of "pre-deformation, energy storage and actuation" and its non-fracture constraint domain. Then, the parameters of SMPCs will be optimized. Theoretical analysis is realized by the strain energy function, additionally considering the interaction strain energy between the fiber and the matrix. For the common resin-based or soft-material-based composites under pure bending deformation, we expect to uniformly explain the whole process of buckling occurrence, evolution and finally failure, especially for the early evolution characteristics of fiber microbuckling inside the microstructures. The research results are meaningful for the practical applications for SMPC deployable structures in space. Considering the deformation mechanisms of SMPCs, the local post-microbuckling is required for the unidirectional fiber reinforced composite materials, at the conditions of its large geometrical deflection. The cross section of SMPC is divided into three areas: non-buckling stretching area, non-buckling compressive area, and buckling compressive area. Three variables are considered: critical buckling position, and neutral plane, the fiber buckling half-wavelength. Considering the condition of the small strain and large displacement, the strain energy expression of the SMP/fiber system was derived, which contains two types, e.g., strain energy of SMP and fiber. According to the minimum energy principle, the expression for all key parameters were derived, including the critical buckling curvature, neutral plane position, the buckling half-wavelength, fiber buckling amplitude, and strain.

Smart phones: platform enabling modular, chemical, biological, and explosives sensing

NASA Astrophysics Data System (ADS)

Finch, Amethist S.; Coppock, Matthew; Bickford, Justin R.; Conn, Marvin A.; Proctor, Thomas J.; Stratis-Cullum, Dimitra N.

2013-05-01

Reliable, robust, and portable technologies are needed for the rapid identification and detection of chemical, biological, and explosive (CBE) materials. A key to addressing the persistent threat to U.S. troops in the current war on terror is the rapid detection and identification of the precursor materials used in development of improvised explosive devices, homemade explosives, and bio-warfare agents. However, a universal methodology for detection and prevention of CBE materials in the use of these devices has proven difficult. Herein, we discuss our efforts towards the development of a modular, robust, inexpensive, pervasive, archival, and compact platform (android based smart phone) enabling the rapid detection of these materials.

MRI-visual order-disorder micellar nanostructures for smart cancer theranostics.

PubMed

Patra, Hirak K; Ul Khaliq, Nisar; Romu, Thobias; Wiechec, Emilia; Borga, Magnus; Turner, Anthony P F; Tiwari, Ashutosh

2014-04-01

The development of MRI-visual order-disorder structures for cancer nanomedicine explores a pH-triggered mechanism for theragnosis of tumor hallmark functions. Superparamagnetic iron oxide nanoparticles (SPIONs) stabilized with amphiphilic poly(styrene)-b-poly(acrylic acid)-doxorubicin with folic acid (FA) surfacing are employed as a multi-functional approach to specifically target, diagnose, and deliver drugs via a single nanoscopic platform for cancer therapy. The functional aspects of the micellar nanocomposite is investigated in vitro using human breast SkBr3 and colon cancer HCT116 cell lines for the delivery, release, localization, and anticancer activity of the drug. For the first time, concentration-dependent T2 -weighted MRI contrast for a monolayer of clustered cancer cells is shown. The pH tunable order-disorder transition of the core-shell structure induces the relative changes in MRI contrast. The outcomes elucidate the potential of this material for smart cancer theranostics by delivering non-invasive real-time diagnosis, targeted therapy, and monitoring the course and response of the action before, during, and after the treatment regimen. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent Progress on Flexible Triboelectric Nanogenerators for SelfPowered Electronics.

PubMed

Hinchet, Ronan; Seung, Wanchul; Kim, Sang-Woo

2015-07-20

Recently, smart systems have met with large success. At the origin of the internet of things, they are a key driving force for the development of wireless, sustainable, and independent autonomous smart systems. In this context, autonomy is critical, and despite all the progress that has been made in low-power electronics and batteries, energy harvesters are becoming increasingly important. Thus, harvesting mechanical energy is essential, as it is widespread and abundant in our daily life environment. Among harvesters, flexible triboelectric nanogenerators (TENGs) exhibit good performance, and they are easy to integrate, which makes them perfect candidates for many applications and, therefore, crucial to develop. In this review paper, we first introduce the fundamentals of TENGs, including their four basic operation modes. Then, we discuss the different improvement parameters. We review some progress made in terms of performance and integration that have been possible through the understanding of each operation mode and the development of innovative structures. Finally, we present the latest trends, structures, and materials in view of future improvements and applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanostructure characteristics of ferroics and bio-ferroics in relation to the design consideration of nano-sensing elements

NASA Astrophysics Data System (ADS)

Pal, Madhuparna

The shift of the epicenter in the field of science and technology to the nano-world has become evident over the past couple of decades with the emergence of areas likes nanoscience, nanotechnology, nano-biotechnology, etc. Though the size of the devices has decreased, the capability of devices has increased rendering it as 'multifunctional/smart' devices. However the design of smart devices using a single phase material has reached to its limit, hence to make further progress "smart materials" are required. Sensors/actuators are mostly fabricated with popular ferroic materials (ferroelectric/ ferromagnetic/ ferroelastic) or multiferroics (having more than one ferroic property). Multifunctionality can be the outcome of heterogeneous systems with cross-coupled properties, intrinsic as well as extrinsic, and hence modeling of smart materials with high figure of merit is also needed. Most ideas in smart sensing and actuation have been borrowed from the biological systems thus a step further is indeed to combine the engineering with the fundamental biological activities. Not only can we use multiferroic materials in artificial transplants, but we should also investigate ferroic activities in the biological samples. These fundamental issues, their possible solutions and their wide impact underlie the motivation of the current work in this thesis report. To achieve the ultimate goal, the steps outlined were followed: i. understanding the properties of sensing elements of inorganic and biomaterials at nanoscale level, ii. investigation of the multiferroicity, iii. modeling engineered material with better sensing capabilities iv. Finally exploiting the new concepts for device and biomedical applications. The findings of this thesis reports multiferroic behavior in a selected class of single crystals, thin films and bulk materials. Human nails and hair samples have been investigated for ferroelectricity and a comprehensive study concludes the presence of bio-ferroelectricity. Bio-ceramic for potential bone replacement has been characterized for its electrical properties and evidence has been given for its suitability. Initiation of modeling of material with high figure of merit for pyroelectric applications has been done which provides a platform to tailor its boundary conditions, interplay of interfaces to obtain meta-property. A broader impact of this thesis was to come forth with ideas to medical diagnostics and health monitoring combining and enhancing the understanding of multiferroics at macro to nano level, modeling of efficient heterogeneous material system, science of bio-materials and applications of bio-ceramics.

Nanomaterials for LightManagement in Electro-Optical Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Truong, Vo-Van; Singh, Jai; Tanemura, Sakae

2012-01-01

In the past decade, nanostructured materials and nanoparticles have emerged as the necessary ingredients for electrooptical applications and enhancement of device performance, in particular by making use of the light management aspects of the nanomaterials. The application areas that are being transformed profoundly include smart coating devices (e.g., electrochromic, photochromic, and thermochromic devices), solar energy, and sensing. Despite the large volume of work in the past on smart coating devices, and in particular on electrochromic devices and thermochromic fenestrations, for optical transmission or reflection control, applications remain limited because of slow response time and nonuniformity in the case of largemore » surfaces. Recent works in the field indicate that nanostructured electrochromic coatings would be an integral part of the solution to the above problem. One aspect that can thus be focused on would be the fabrication and characterization of the nanostructured smart coating materials and their compatibility with other layers in the overall smart coating device. In the area of solar photovoltaics, nanomaterials have been used in designing light-trapping schemes for inorganic as well as organic solar cells. One particular category of solar cells that has attracted much interest is the plasmonic solar cells in which metallic nanoparticles are incorporated, helping in enhancing their energy conversion efficiency. Nanostructured solar cells would eventually develop into a 'game changing' technology for making solar cells that are affordable and highly efficient, providing a sizeable alternative energy source for our ever-increasing energy needs. Sensors based on the optical properties of constituting nanostructures and nanoparticles also form a most interesting class of bio- and electrochemical sensing devices. The possibility of synthetizing nanoparticles and structures of specifically desired sizes and shapes has indeed opened a whole new range of sensing applications. In parallel to the experimental development of nanomaterials for light management in devices, theoretical modeling and analysis have also accomplished much progress, and different methods for simulating the optical properties of nanoparticles and structures have been proposed. This special issue of the Journal of Nanomaterials is thus dedicated to articles dealing with nanostructured materials that can be used for light management purpose in different applications. Silicon-rich oxide (SRO) is a dielectric material that contains Si nanoparticles and exhibits interesting physical characteristics for applications in optoelectronic devices. The work by Aceves-Mijares et al. examine, in detail the electro-, cathode- and photoluminescence properties of SRO and discuss the origin of light emission in this type of materials. SRO films, of high and medium silicon excess density, obtained by low-pressure chemical vapor deposition and annealed at 1,100 C have been studied. Results obtained by the authors have led to conclude that SRO emission properties are due to oxidation state nanoagglomerates rather than to nanocrystals, and the emission mechanism is similar to that in the donor-acceptor decay in semiconductors with a specific wide emission spectrum. Two papers are devoted to nanostructured electrochromic thin films, a category of materials most suitable for controlling light transmission or absorption in electrooptical devices, including smart window coatings. Dinh et al. have shown that by mixing nanostructured Ti and W oxides films, one can obtain devices with considerable enhancement of electrochromic efficiency and electrochemical stability as compared to the conventional nonnanostructured films. As large-area mixed Ti and W oxides can be prepared by the simple doctor blade technique followed by an electrochemical process, this type of nanostructured electrochromic films can be considered a good candidate for smart window applications. Djaoued et al. have presented their studies on the synthesis, characterization, and electrochromic applications of porous WO{sub 3} thin films with different nanocrystalline phases. Asymmetric type electrochromic devices have been constructed using hexagonal, monoclinic, and orthorhombic porous WO{sub 3} thin porous films, and their enhanced electrochromic functionality has been well demonstrated. The paper on smart materials by Chen et al. presents the synthesis of thermochromic W-doped VO{sub 2} (monoclinic/rutile) nanopowders using a novel and simple solution-based process as opposed to other conventional techniques such as excimer laser-assisted metal organic deposition and magnetron sputtering. This simple process is based on the reaction of ammonium metavanadate (NH{sub 4}VO{sub 3}) and oxalic acid dihydrate (C{sub 2}H{sub 2}O{sub 4} {center_dot} 2H{sub 2}O) followed by addition of appropriate ammonium tungstate (N{sub 5}H{sub 37}W{sub 6}O{sub 24} {center_dot} H{sub 2}O).« less

Estimation of Prestress Force Distribution in Multi-Strand System of Prestressed Concrete Structures Using Field Data Measured by Electromagnetic Sensor

PubMed Central

Cho, Keunhee; Cho, Jeong-Rae; Kim, Sung Tae; Park, Sung Yong; Kim, Young-Jin; Park, Young-Hwan

2016-01-01

The recently developed smart strand can be used to measure the prestress force in the prestressed concrete (PSC) structure from the construction stage to the in-service stage. The higher cost of the smart strand compared to the conventional strand renders it unaffordable to replace all the strands by smart strands, and results in the application of only a limited number of smart strands in the PSC structure. However, the prestress forces developed in the strands of the multi-strand system frequently adopted in PSC structures differ from each other, which means that the prestress force in the multi-strand system cannot be obtained by simple proportional scaling using the measurement of the smart strand. Therefore, this study examines the prestress force distribution in the multi-strand system to find the correlation between the prestress force measured by the smart strand and the prestress force distribution in the multi-strand system. To that goal, the prestress force distribution was measured using electromagnetic sensors for various factors of the multi-strand system adopted on site in the fabrication of actual PSC girders. The results verified the possibility to assume normal distribution for the prestress force distribution per anchor head, and a method computing the mean and standard deviation defining the normal distribution is proposed. This paper presents a meaningful finding by proposing an estimation method of the prestress force based upon field-measured data of the prestress force distribution in the multi-strand system of actual PSC structures. PMID:27548172

Multi-channel measurement for hetero-core optical fiber sensor by using CMOS camera

NASA Astrophysics Data System (ADS)

Koyama, Yuya; Nishiyama, Michiko; Watanabe, Kazuhiro

2015-07-01

Fiber optic smart structures have been developed over several decades by the recent fiber optic sensor technology. Optical intensity-based sensors, which use LD or LEDs, can be suitable for the monitor system to be simple and cost effective. In this paper, a novel fiber optic smart structure with human-like perception has been demonstrated by using intensity-based hetero-core optical fiber sensors system with the CMOS detector. The optical intensity from the hetero-core optical fiber bend sensor is obtained as luminance spots indicated by the optical power distributions. A number of optical intensity spots are simultaneously readout by taking a picture of luminance pattern. To recognize the state of fiber optic smart structure with the hetero-core optical fibers, the template matching process is employed with Sum of Absolute Differences (SAD). A fiber optic smart glove having five optic fiber nerves have been employed to monitor hand postures. Three kinds of hand postures have been recognized by means of the template matching process. A body posture monitoring has also been developed by placing the wearable hetero-core optical fiber bend sensors on the body segments. In order for the CMOS system to be a human brain-like, the luminescent spots in the obtained picture were arranged to make the pattern corresponding to the position of body segments. As a result, it was successfully demonstrated that the proposed fiber optic smart structure could recognize eight kinds of body postures. The developed system will give a capability of human brain-like processing to the existing fiber optic smart structures.

Carbon Smackdown: Smart Windows (LBNL Summer Lecture Series)

ScienceCinema

Milliron, Delia; Selkowitz, Stephen

2017-12-09

August 3, 2010 Berkeley Lab talk: In the fourth of five Carbon Smackdown matches, Berkeley Lab researchers Delia Milliron of the Materials Sciences Division and Stephen Selkowitz of the Environmental Energy Technologies Division talk about their work on energy-saving smart windows.

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Ardani, Kristen; Cutler, Dylan

Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domesticmore » water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.« less

Solar Plus: A Holistic Approach to Distributed Solar PV

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J.; Ardani, Kristen B.; Cutler, Dylan S.

Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domesticmore » water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.« less

Autonomous smart sensor network for full-scale structural health monitoring

NASA Astrophysics Data System (ADS)

Rice, Jennifer A.; Mechitov, Kirill A.; Spencer, B. F., Jr.; Agha, Gul A.

2010-04-01

The demands of aging infrastructure require effective methods for structural monitoring and maintenance. Wireless smart sensor networks offer the ability to enhance structural health monitoring (SHM) practices through the utilization of onboard computation to achieve distributed data management. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While smart sensor technology is not new, the number of full-scale SHM applications has been limited. This slow progress is due, in part, to the complex network management issues that arise when moving from a laboratory setting to a full-scale monitoring implementation. This paper presents flexible network management software that enables continuous and autonomous operation of wireless smart sensor networks for full-scale SHM applications. The software components combine sleep/wake cycling for enhanced power management with threshold detection for triggering network wide tasks, such as synchronized sensing or decentralized modal analysis, during periods of critical structural response.

Biomimetic actuators using electroactive polymers (EAP) as artificial muscles

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2006-01-01

Evolution has resolved many of nature's challenges leading to lasting solutions with maximal performance and effective use of resources. Nature's inventions have always inspired human achievements leading to effective materials, structures, tools, mechanisms, processes, algorithms, methods, systems and many other benefits. The field of mimicking nature is known as Biomimetics and one of its topics includes electroactive polymers that gain the moniker artificial muscles. Integrating EAP with embedded sensors, self-repair and many other capabilities that are used in composite materials can add greatly to the capability of smart biomimetic systems. Such development would enable fascinating possibilities potentially turning science fiction ideas into engineering reality.

Smart fabrics: integrating fiber optic sensors and information networks.

PubMed

El-Sherif, Mahmoud

2004-01-01

"Smart Fabrics" are defined as fabrics capable of monitoring their own "health", and sensing environmental conditions. They consist of special type of sensors, signal processing, and communication network embedded into textile substrate. Available conventional sensors and networking systems are not fully technologically mature for such applications. New classes of miniature sensors, signal processing and networking systems are urgently needed for such application. Also, the methodology for integration into textile structures has to be developed. In this paper, the development of smart fabrics with embedded fiber optic systems is presented for applications in health monitoring and diagnostics. Successful development of such smart fabrics with embedded sensors and networks is mainly dependent on the development of the proper miniature sensors technology, and on the integration of these sensors into textile structures. The developed smart fabrics will be discussed and samples of the results will be presented.

VO2 microcrystals as an advanced smart window material at semiconductor to metal transition

NASA Astrophysics Data System (ADS)

Basu, Raktima; Magudapathy, P.; Sardar, Manas; Pandian, Ramanathaswamy; Dhara, Sandip

2017-11-01

Textured VO2(0 1 1) microcrystals are grown in the monoclinic, M1 phase which undergoes a reversible first order semiconductor to metal transition (SMT) accompanied by a structural phase transition to rutile tetragonal, R phase. Around the phase transition, VO2 also experiences noticeable change in its optical and electrical properties. A change in color of the VO2 micro crystals from white to cyan around the transition temperature is observed, which is further understood by absorption of red light using temperature dependent ultraviolet-visible spectroscopic analysis and photoluminescence studies. The absorption of light in the red region is explained by the optical transition between Hubbard states, confirming the electronic correlation as the driving force for SMT in VO2. The thermochromism in VO2 has been studied for smart window applications so far in the IR region, which supports the opening of the band gap in semiconducting phase; whereas there is hardly any report in the management of visible light. The filtering of blue light along with reflection of infrared above the semiconductor to metal transition temperature make VO2 applicable as advanced smart windows for overall heat management of a closure.

Improved actuation strain of PDMS-based DEA materials chemically modified with softening agents

NASA Astrophysics Data System (ADS)

Biedermann, Miriam; Blümke, Martin; Wegener, Michael; Krüger, Hartmut

2015-04-01

Dielectric elastomer actuators (DEAs) are smart materials that gained much in interest particularly in recent years. One active field of research is the improvement of their properties by modification of their structural framework. The object of this work is to improve the actuation properties of polydimethylsiloxane (PDMS)-based DEAs by covalent incorporation of mono-vinyl-terminated low-molecular PDMS chains into the PDMS network. These low-molecular units act as a kind of softener within the PDMS network. The loose chain ends interfere with the network formation and lower the network's density. PDMS films with up to 50wt% of low-molecular PDMS additives were manufactured and the chemical, mechanical, electrical, and electromechanical properties of these novel materials were investigated.

Fiber optic sensor technology - An opportunity for smart aerospace structures

NASA Technical Reports Server (NTRS)

Heyman, J. S.; Rogowski, R. S.; Claus, R. O.

1988-01-01

Fiber optic sensors provide the opportunity for fabricating materials with internal sensors which can serve as lifetime health monitors, analogous to a central nervous system. The embedded fiber optic sensors can be interrogated by various techniques to measure internal strain, temperature, pressure, acoustic waves and other parameters indicative of structural integrity. Experiments have been conducted with composite samples with embedded sensors to measure strain using optical time domain reflectometry, modal interference and an optical phase locked loop. Fiber optic sensors have been developed to detect acoustic emission and impact damage and have been demonstrated for cure monitoring. These sensors have the potential for lifetime monitoring of structural properties, providing real time nondestructive evaluation.

Dissemination of go sun smart in outdoor recreation: effect of program exposure on sun protection of guests at high-altitude ski areas.

PubMed

Walkosz, Barbara J; Buller, David B; Andersen, Peter A; Scott, Michael D; Dignan, Mark B; Cutter, Gary R; Liu, Xia; Maloy, Julie A

2014-09-01

Go Sun Smart is a theory-based health communication program designed to influence sun-protection behaviors of employees and guests at high-altitude ski areas to reduce skin cancer risk. The effects of Go Sun Smart, in a Phase IV dissemination randomized posttest-only trial, on sun-protection behaviors of ski area guests are reported. Program use was assessed by on-site observation and guest message exposure, and sun protection was measured in intercept surveys at ski areas. Dissemination strategy-enhanced versus basic-was not significantly related to sun safety practices. Additional analyses examined the relation between message exposure and guests' sun safety practices. Ski areas displaying at least 6 Go Sun Smart materials in guest-only areas and 9 Go Sun Smart materials throughout the area increased guests' message exposure. Higher message exposure within the high-use ski areas was associated with improved sun protection by guests but not within the low-use ski areas. The authors underscore the importance of program implementation and message exposure on the success of evidence-based health communication efforts applied industrywide.

Thermoviscosifying Smart Polymers for Oil and Gas Production: State of the Art.

PubMed

Feng, Yujun; Su, Xin

2018-06-11

Water-soluble polymers have been extensively used in all sections of oil and gas upstream industry, but the inherent thermothinning behaviours limited their applications in harsh environment. To address this issue, thermoviscosifying (or "thermothickening") polymers (TVPs) whose aqueous solution viscosity automatically increase upon increasing temperature was introduced early 1990s. This review started with recalling the background for developing such smart materials, followed by demonstrating the mechanism of thermothickening. Next, three major TVPs including N-alkyl substituted acrylamide copolymers, grafted polyethers and cellulose derivatives were summarized with respect to their structure-property relationship, then their practical trials or potential uses in oil and gas drilling fluids, cementing slurries, hydraulic fracturing, steam flooding and enhanced oil recovery were discussed. Finally, the advantages and disadvantages of the current TVPs were commented, and the future prospects were outlooked to close this review. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Smart Superwetting Surface with Responsivity in Both Surface Chemistry and Microstructure.

PubMed

Zhang, Dongjie; Cheng, Zhongjun; Kang, Hongjun; Yu, Jianxin; Liu, Yuyan; Jiang, Lei

2018-03-26

Recently, smart surfaces with switchable wettability have aroused much attention. However, only single surface chemistry or the microstructure can be changed on these surfaces, which significantly limits their wetting performances, controllability, and applications. A new surface with both tunable surface microstructure and chemistry was prepared by grafting poly(N-isopropylacrylamide) onto the pillar-structured shape memory polymer on which multiple wetting states from superhydrophilicity to superhydrophobicity can be reversibly and precisely controlled by synergistically regulating the surface microstructure and chemistry. Meanwhile, based on the excellent controllability, we also showed the application of the surface as a rewritable platform, and various gradient wettings can be obtained. This work presents for the first time a surface with controllability in both surface chemistry and microstructure, which starts some new ideas for the design of novel superwetting materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phononic Crystal Tunable via Ferroelectric Phase Transition

NASA Astrophysics Data System (ADS)

Xu, Chaowei; Cai, Feiyan; Xie, Shuhong; Li, Fei; Sun, Rong; Fu, Xianzhu; Xiong, Rengen; Zhang, Yi; Zheng, Hairong; Li, Jiangyu

2015-09-01

Phononic crystals (PCs) consisting of periodic materials with different acoustic properties have potential applications in functional devices. To realize more smart functions, it is desirable to actively control the properties of PCs on demand, ideally within the same fabricated system. Here, we report a tunable PC made of Ba0.7Sr0.3Ti O3 (BST) ceramics, wherein a 20-K temperature change near room temperature results in a 20% frequency shift in the transmission spectra induced by a ferroelectric phase transition. The tunability phenomenon is attributed to the structure-induced resonant excitation of A0 and A1 Lamb modes that exist intrinsically in the uniform BST plate, while these Lamb modes are sensitive to the elastic properties of the plate and can be modulated by temperature in a BST plate around the Curie temperature. The study finds opportunities for creating tunable PCs and enables smart temperature-tuned devices such as the Lamb wave filter or sensor.

New oxidation-resistant tungsten alloys for use in the nuclear fusion reactors

NASA Astrophysics Data System (ADS)

Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch; Rasinski, M.; Kreter, A.; Tan, X.; Schmitz, J.; Coenen, J. W.; Mao, Y.; Gonzalez-Julian, J.; Bram, M.

2017-12-01

Smart tungsten-based alloys are under development as plasma-facing components for a future fusion power plant. Smart alloys are planned to adjust their properties depending on environmental conditions: acting as a sputter-resistant plasma-facing material during plasma operation and suppressing the sublimation of radioactive tungsten oxide in case of an accident on the power plant. New smart alloys containing yttrium are presently in the focus of research. Thin film smart alloys are featuring an remarkable 105-fold suppression of mass increase due to an oxidation as compared to that of pure tungsten at 1000 °C. Newly developed bulk smart tungsten alloys feature even better oxidation resistance compared to that of thin films. First plasma test of smart alloys under DEMO-relevant conditions revealed the same mass removal as for pure tungsten due to sputtering by plasma ions. Exposed smart alloy samples demonstrate the superior oxidation performance as compared to tungsten-chromium-titanium systems developed earlier.

Smart particles for noble drug delivery system.

PubMed

Park, Cheolyoung; Kim, Jihoon; Jang, Seunghyun; Woo, Hee-Gweon; Ko, Young Chun; Sohn, Honglae

2010-05-01

Optically encoded smart particles were prepared for noble drug delivery materials. Distributed Bragg reflector (DBR) porous silicon (PSi) was generated by applying a computer-generated pseudo-square wave current waveform. This DBR PSi film was lifted off from the Si substrate and thermally oxidized to convert PSi to porous silicon dioxide (PSD). DBR PSD film was derivatized with 20(S)-Camptothecin (CPT) and fractured by ultrasono-method to give smart particles. DBR PSD smart particles exhibited a sharp photonic band gap in the optical reflectivity spectrum. Optical characteristic of PSD smart particles retained DBR photonic property in aqueous buffer solution. The release of CPT and change of reflection wavelength were measured by UV-vis and reflectance spectrometer, respectively. The intensity of differential peak from reflection resonances of the smart particles was increased with a drug release. The blue shift of reflection peak resulted in the decrease of refractive index of PSD smart particles during the drug release. The concentration of released drug exhibited an linear relationship with a release time.

Fully Roll-to-Roll Gravure Printable Wireless (13.56 MHz) Sensor-Signage Tags for Smart Packaging

NASA Astrophysics Data System (ADS)

Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

2014-06-01

Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging.

Fully Roll-to-Roll Gravure Printable Wireless (13.56 MHz) Sensor-Signage Tags for Smart Packaging

PubMed Central

Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

2014-01-01

Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging. PMID:24953037

Fully roll-to-roll gravure printable wireless (13.56 MHz) sensor-signage tags for smart packaging.

PubMed

Kang, Hwiwon; Park, Hyejin; Park, Yongsu; Jung, Minhoon; Kim, Byung Chul; Wallace, Gordon; Cho, Gyoujin

2014-06-23

Integration of sensing capabilities with an interactive signage through wireless communication is enabling the development of smart packaging wherein wireless (13.56 MHz) power transmission is used to interlock the smart packaging with a wireless (13.56 MHz) reader or a smart phone. Assembly of the necessary componentry for smart packaging on plastic or paper foils is limited by the manufacturing costs involved with Si based technologies. Here, the issue of manufacturing cost for smart packaging has been obviated by materials that allow R2R (roll-to-roll) gravure in combination with R2R coating processes to be employed. R2R gravure was used to print the wireless power transmission device, called rectenna (antenna, diode and capacitor), and humidity sensor on poly(ethylene terephtalate) (PET) films while electrochromic signage units were fabricated by R2R coating. The signage units were laminated with the R2R gravure printed rectenna and sensor to complete the prototype smart packaging.

Postgraduate education on electro-active polymers at Southern Denmark University

NASA Astrophysics Data System (ADS)

Jones, Richard W.

2009-03-01

A recently introduced elective to the Master's of Science in Mechatronics program at Southern Denmark University, entitled 'Mechatronics: Design and Build' concentrates on some of the interdisciplinary aspects of Mechatronics Engineering. The 'Motion Control of Mechatronic Devices' is the main theme of this elective. Within this 'theme' the modelling, identification and compensation of nonlinear effects such as friction, stiction and hysteresis are considered. One of the most important components of the elective considers 'Smart Materials' and their use for actuation purposes. The theory, modelling and properties of piezoceramics. magneto- and electro- rheological fluids and dielectric electro active polymers (DEAP) are introduced in the 'Smart Materials' component. This paper initially reviews the laboratory experiments that have been developed for the dielectric electro active polymer section of the 'Mechatronics: Design and Build' elective. In lectures the students are introduced to the basic theory and fabrication of tubular actuators, that use DEAP material based on smart compliant electrode technology. In the laboratory the students to (a) carry out a series of experiments to characterise the tubular actuators, and (b) design a closed-loop position controller and test the performance of the controlled actuator for both step changes in desired position and periodic input reference signals. The last part of this contribution reviews some of the DEAP-based demonstration devices that been developed by Danfoss PolyPower A/S using their PolyPowerTM material which utilizes smart compliant electrode technology.

Smart fabric sensors and e-textile technologies: a review

NASA Astrophysics Data System (ADS)

Castano, Lina M.; Flatau, Alison B.

2014-05-01

This paper provides a review of recent developments in the rapidly changing and advancing field of smart fabric sensor and electronic textile technologies. It summarizes the basic principles and approaches employed when building fabric sensors as well as the most commonly used materials and techniques used in electronic textiles. This paper shows that sensing functionality can be created by intrinsic and extrinsic modifications to textile substrates depending on the level of integration into the fabric platform. The current work demonstrates that fabric sensors can be tailored to measure force, pressure, chemicals, humidity and temperature variations. Materials, connectors, fabric circuits, interconnects, encapsulation and fabrication methods associated with fabric technologies prove to be customizable and versatile but less robust than their conventional electronics counterparts. The findings of this survey suggest that a complete smart fabric system is possible through the integration of the different types of textile based functional elements. This work intends to be a starting point for standardization of smart fabric sensing techniques and e-textile fabrication methods.

How to be smart and energy efficient: A general discussion on thermochromic windows

PubMed Central

Long, Linshuang; Ye, Hong

2014-01-01

A window is a unique element in a building because of its simultaneous properties of being “opaque” to inclement weather yet transparent to the observer. However, these unique features make the window an element that can reduce the energy efficiency of buildings. A thermochromic window is a type of smart window whose solar radiation properties vary with temperature. It is thought that the solar radiation gain of a room can be intelligently regulated through the use of thermochromic windows, resulting in lower energy consumption than with standard windows. Materials scientists have made many efforts to improve the performance of thermochromic materials. Despite these efforts, fundamental problems continue to confront us. How should a “smart” window behave? Is a “smart” window really the best candidate for energy-efficient applications? What is the relationship between smartness and energy performance? To answer these questions, a general discussion of smartness and energy performance is provided. PMID:25233891

Consensus positive position feedback control for vibration attenuation of smart structures

NASA Astrophysics Data System (ADS)

Omidi, Ehsan; Nima Mahmoodi, S.

2015-04-01

This paper presents a new network-based approach for active vibration control in smart structures. In this approach, a network with known topology connects collocated actuator/sensor elements of the smart structure to one another. Each of these actuators/sensors, i.e., agent or node, is enhanced by a separate multi-mode positive position feedback (PPF) controller. The decentralized PPF controlled agents collaborate with each other in the designed network, under a certain consensus dynamics. The consensus constraint forces neighboring agents to cooperate with each other such that the disagreement between the time-domain actuation of the agents is driven to zero. The controller output of each agent is calculated using state-space variables; hence, optimal state estimators are designed first for the proposed observer-based consensus PPF control. The consensus controller is numerically investigated for a flexible smart structure, i.e., a thin aluminum beam that is clamped at its both ends. Results demonstrate that the consensus law successfully imposes synchronization between the independently controlled agents, as the disagreements between the decentralized PPF controller variables converge to zero in a short time. The new consensus PPF controller brings extra robustness to vibration suppression in smart structures, where malfunctions of an agent can be compensated for by referencing the neighboring agents’ performance. This is demonstrated in the results by comparing the new controller with former centralized PPF approach.

Statistical analysis of modal properties of a cable-stayed bridge through long-term structural health monitoring with wireless smart sensor networks

NASA Astrophysics Data System (ADS)

Asadollahi, Parisa; Li, Jian

2016-04-01

Understanding the dynamic behavior of complex structures such as long-span bridges requires dense deployment of sensors. Traditional wired sensor systems are generally expensive and time-consuming to install due to cabling. With wireless communication and on-board computation capabilities, wireless smart sensor networks have the advantages of being low cost, easy to deploy and maintain and therefore facilitate dense instrumentation for structural health monitoring. A long-term monitoring project was recently carried out for a cable-stayed bridge in South Korea with a dense array of 113 smart sensors, which feature the world's largest wireless smart sensor network for civil structural monitoring. This paper presents a comprehensive statistical analysis of the modal properties including natural frequencies, damping ratios and mode shapes of the monitored cable-stayed bridge. Data analyzed in this paper is composed of structural vibration signals monitored during a 12-month period under ambient excitations. The correlation between environmental temperature and the modal frequencies is also investigated. The results showed the long-term statistical structural behavior of the bridge, which serves as the basis for Bayesian statistical updating for the numerical model.

Long-term real-time structural health monitoring using wireless smart sensor

NASA Astrophysics Data System (ADS)

Jang, Shinae; Mensah-Bonsu, Priscilla O.; Li, Jingcheng; Dahal, Sushil

2013-04-01

Improving the safety and security of civil infrastructure has become a critical issue for decades since it plays a central role in the economics and politics of a modern society. Structural health monitoring of civil infrastructure using wireless smart sensor network has emerged as a promising solution recently to increase structural reliability, enhance inspection quality, and reduce maintenance costs. Though hardware and software framework are well prepared for wireless smart sensors, the long-term real-time health monitoring strategy are still not available due to the lack of systematic interface. In this paper, the Imote2 smart sensor platform is employed, and a graphical user interface for the long-term real-time structural health monitoring has been developed based on Matlab for the Imote2 platform. This computer-aided engineering platform enables the control, visualization of measured data as well as safety alarm feature based on modal property fluctuation. A new decision making strategy to check the safety is also developed and integrated in this software. Laboratory validation of the computer aided engineering platform for the Imote2 on a truss bridge and a building structure has shown the potential of the interface for long-term real-time structural health monitoring.

Integrated smart structures wingbox

NASA Astrophysics Data System (ADS)

Simon, Solomon H.

1993-09-01

One objective of smart structures development is to demonstrate the ability of a mechanical component to monitor its own structural integrity and health. Achievement of this objective requires the integration of different technologies, i.e.: (1) structures, (2) sensors, and (3) artificial intelligence. We coordinated a team of experts from these three fields. These experts used reliable knowledge towards the forefront of their technologies and combined the appropriate features into an integrated hardware/software smart structures wingbox (SSW) test article. A 1/4 in. hole was drilled into the SSW test article. Although the smart structure had never seen damage of this type, it correctly recognized and located the damage. Based on a knowledge-based simulation, quantification and assessment were also carried out. We have demonstrated that the SSW integrated hardware & software test article can perform six related functions: (1) identification of a defect; (2) location of the defect; (3) quantification of the amount of damage; (4) assessment of performance degradation; (5) continued monitoring in spite of damage; and (6) continuous recording of integrity data. We present the successful results of the integrated test article in this paper, along with plans for future development and deployment of the technology.

Smart wing wind tunnel model design

NASA Astrophysics Data System (ADS)

Martin, Christopher A.; Jasmin, Larry; Flanagan, John S.; Appa, Kari; Kudva, Jayanth N.

1997-05-01

To verify the predicted benefits of the smart wing concept, two 16% scale wind tunnel models, one conventional and the other incorporating smart wing design features, were designed, fabricated and tested. Meticulous design of the two models was essential to: (1) ensure the required factor of safety of four for operation in the NASA Langley TDT wind tunnel, (2) efficiently integrate the smart actuation systems, (3) quantify the performance improvements, and (4) facilitate eventual scale-up to operational aircraft. Significant challenges were encountered in designing the attachment of the shape memory alloy control surfaces to the wing box, integration of the SMA torque tube in the wing structure, and development of control mechanisms to protect the model and the tunnel in the event of failure of the smart systems. In this paper, detailed design of the two models are presented. First, dynamic scaling of the models based on the geometry and structural details of the full- scale aircraft is presented. Next, results of the stress, divergence and flutter analyses are summarized. Finally some of the challenges of integrating the smart actuators with the model are highlighted.

Modeling and Bayesian Parameter Estimation for Shape Memory Alloy Bending Actuators

DTIC Science & Technology

2012-02-01

prosthetic hand,” Technology and Health Care 10, 91–106 (2002). 4. Hartl , D., Lagoudas, D., Calkins, F., and Mabe , J., “Use of a ni60ti shape memory...alloy for active jet engine chevron application: I. thermomechanical characterization,” Smart Materials and Structures 19, 1–14 (2010). 5. Hartl , D...Lagoudas, D., Calkins, F., and Mabe , J., “Use of a ni60ti shape memory alloy for active jet engine chevron application: II. experimentally validated

Electrorheological fluids and methods

DOEpatents

Green, Peter F.; McIntyre, Ernest C.

2015-06-02

Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.

New Materials for Smart Structures: a US: Japan Global Initiative

DTIC Science & Technology

2004-03-01

realization of the MPB in the Gallate:Scandate system and in the modified bismuth lanthanum ferrate lead titanate systems. A major puzzle in BiFeO3 which has...magnetization. A new major clue as to the origin of the high switchable polarization is provided by our most recent work on the modified bismuth lanthanum ...ferrate: gallate solid solutions with MPBs. In suitable composition switchability is only possible with limited electrode in a larger disk, and the fully

U.S. Army Research Office Workshop on Smart Materials, Structures and Mathematical Issues Held in Blacksburg, Virginia on 15-16 September 1988

DTIC Science & Technology

1989-01-01

prestrained Nitinol (an alloy of nickel and titanium) wires are embedded in an off-axis position in the graphite fiber reinforced epoxy composite beam... Nitinol ) alloy. Shape memory alloys have been applied to a number of items including connectors and heat engines, but have usually found application in... nitinol wire; the design includes prevention from ancillary jams. Miwa (1985) discusses the use of SMA actuator to sequential robotic control of multiple

Materials for Adaptive Structural Acoustic Control. Volume 4

DTIC Science & Technology

1993-04-06

Ceramics: Pioeprues- [kvjcecs 1. R.E. Newnham and G. R. Ruschau, "Smart Electrocerarnics." 3A . and Aplication , ed. by L.M. Levinson, Marcel Dekker...TechniQue (Ph. D Thesis , The Pennsylvania State University, University Park, 1990). 8. J.K. Yamamoto and A.S. Bhalla, Mater. Lett., 1-0, 497 (1991). 9...explained flr Ceramic Capacitors". M S Thesi , Penn,,yl’ania State Uni.ersitw. L nie.by the Maxwell-Wagner model and experimental data fitted sily Park. PA

A Coupled Layerwise Analysis of the Thermopiezoelectric Response of Smart Composite Beams Beams

NASA Technical Reports Server (NTRS)

Lee, H.-J.; Saravanos, D. A.

1995-01-01

Thermal effects are incorporated into previously developed discrete layer mechanics for piezoelectric composite beam structures. The updated mechanics explicitly account for the complete coupled thermoelectromechanical response of smart composite beams. This unified representation leads to an inherent capability to model both the sensory and actuator responses of piezoelectric composite beams in a thermal environment. Finite element equations are developed and numerical results are presented to demonstrate the capability of the current formulation to represent the behavior of both sensory and active smart structures under thermal loadings.

[Spectral analysis of fiber bragg grating modulated by double long period grating and its application in smart structure monitoring].

PubMed

Lu, Ji-Yun; Liang, Da-Kai; Zhang, Xiao-Li; Zhu, Zhu

2009-12-01

Spectrum of fiber bragg grating (FBG) sensor modulated by double long period grating (LPFG) is proposed in the paper. Double LPFG consists of two LPFGS whose center wavelengths are the same and reflection spectrum of FBG sensor is located in linear range of double LPFG transmission spectrum. Based on spectral analysis of FBG and double LPFG, reflection spectrum of FBG modulated by double LPFG is obtained and studied by use of band-hider filter characteristics for double LPFG. An FBG sensor is attached on the surface of thin steel beam, which is strained by bending, and the center wavelength of FBG sensor will shift. The spectral peak of FBG sensor modulated by double LPFG is changed correspondingly, and the spectral change will lead to variation in exit light intensity from double LPFG. Experiment demonstrates that the relation of filtering light intensity from double LPFG monitored by optical power meter to center wavelength change of FBG sensor is linear and the minimum strain of material (steel beam) detected by the modulation and demodulation system is 1.05 microepsilon. This solution is used in impact monitoring of optical fibre smart structure, and FBG sensor is applied for impulse response signal monitoring induced by low-velocity impact, when impact pendulum is loaded to carbon fiber-reinforced plastics (CFP). The acquired impact response signal and fast Fourier transform of the signal detected by FBG sensor agree with the measurement results of eddy current displacement meter attached to the FBG sensor. From the results, the present method using FBG sensor is found to be effective for monitoring the impact. The research provides a practical reference in dynamic monitoring of optical fiber smart structure field.

Recent advancements in the cobalt oxides, manganese oxides and their composite as an electrode material for supercapacitor: a review

NASA Astrophysics Data System (ADS)

Uke, Santosh J.; Akhare, Vijay P.; Bambole, Devidas R.; Bodade, Anjali B.; Chaudhari, Gajanan N.

2017-08-01

In this smart edge, there is an intense demand of portable electronic devices such as mobile phones, laptops, smart watches etc. That demands the use of such components which has light weight, flexible, cheap and environmental friendly. So that needs an evolution in technology. Supercapacitors are energy storage devices emerging as one of the promising energy storage devices in the future energy technology. Electrode material is the important part of supercapacitor. There is much new advancement in types of electrode materials as for supercapacitor. In this review, we focused on the recent advancements in the cobalt oxides, manganese oxides and their composites as an electrodes material for supercapacitor.

Review on Variable Emissivity Materials and Devices Based on Smart Chromism

NASA Astrophysics Data System (ADS)

Lang, FengPei; Wang, Hao; Zhang, ShengJun; Liu, JingBing; Yan, Hui

2018-01-01

Variable emissivity material (VEM) can dynamically vary its emissivity and infrared radiation under certain conditions, which may find potential applications in infrared stealth/camouflage, solar thermal collector, spacecraft thermal control, and smart energy-saving windows. In this paper, the variable emissivity materials and devices based on electrochromism and thermochromism are introduced. The basic principle and present status of the research in these fields are overviewed. Four kinds of representative VEMs are extensively summarized, which are tungsten trioxides (WO3), conducting polymers (CPs), perovskite oxides (A_{1-{x}}B_{{x}}MO3), and vanadium dioxide (VO2). Finally, specific issues confronted with electrochromic and thermochromic materials and devices are prospected.

Autonomous self-powered structural health monitoring system

NASA Astrophysics Data System (ADS)

Qing, Xinlin P.; Anton, Steven R.; Zhang, David; Kumar, Amrita; Inman, Daniel J.; Ooi, Teng K.

2010-03-01

Structural health monitoring technology is perceived as a revolutionary method of determining the integrity of structures involving the use of multidisciplinary fields including sensors, materials, system integration, signal processing and interpretation. The core of the technology is the development of self-sufficient systems for the continuous monitoring, inspection and damage detection of structures with minimal labor involvement. A major drawback of the existing technology for real-time structural health monitoring is the requirement for external electrical power input. For some applications, such as missiles or combat vehicles in the field, this factor can drastically limit the use of the technology. Having an on-board electrical power source that is independent of the vehicle power system can greatly enhance the SHM system and make it a completely self-contained system. In this paper, using the SMART layer technology as a basis, an Autonomous Self-powered (ASP) Structural Health Monitoring (SHM) system has been developed to solve the major challenge facing the transition of SHM systems into field applications. The architecture of the self-powered SHM system was first designed. There are four major components included in the SHM system: SMART Layer with sensor network, low power consumption diagnostic hardware, rechargeable battery with energy harvesting device, and host computer with supporting software. A prototype of the integrated self-powered active SHM system was built for performance and functionality testing. Results from the evaluation tests demonstrated that a fully charged battery system is capable of powering the SHM system for active scanning up to 10 hours.

Smart nanosystems: Bio-inspired technologies that interact with the host environment.

PubMed

Kwon, Ester J; Lo, Justin H; Bhatia, Sangeeta N

2015-11-24

Nanoparticle technologies intended for human administration must be designed to interact with, and ideally leverage, a living host environment. Here, we describe smart nanosystems classified in two categories: (i) those that sense the host environment and respond and (ii) those that first prime the host environment to interact with engineered nanoparticles. Smart nanosystems have the potential to produce personalized diagnostic and therapeutic schema by using the local environment to drive material behavior and ultimately improve human health.

EcoSmart Fire as structure ignition model in wildland urban interface: predictions and validations

Treesearch

Mark A. Dietenberger; Charles R. Boardman

2016-01-01

EcoSmartFire is a Windows program that models heat damage and piloted ignition of structures from radiant exposure to discrete landscaped tree fires. It calculates the radiant heat transfer from cylindrical shaped fires to the walls and roof of the structure while accounting for radiation shadowing, attenuation, and ground reflections. Tests of litter burn, a 0.6 m...

Development of engineering components having dual functionality

NASA Astrophysics Data System (ADS)

Thompson, L. D.; Waldbusser, R.; Pratt, E.

2000-05-01

This paper describes the engineering research and development of a smart aircraft bolt designed for high-tension wing attachment applications on USAF C-130 cargo planes. The bolt is a load-carrying structural component as well as serving as a damage sensor. The bolt material choice is TRIP (Transformation Induced Plasticity) steel; high-strength, metastable austenitic steel that gradually and irreversibly transforms to martensite during deformation. The martensite is ferromagnetic whereas the parent austenite phase is paramagnetic, having no significant ferromagnetic response. The ferromagnetic signature of the bolt can be correlated to the peak deformation strain and further correlated with the peak damage state. Stress-assisted phase transformations occur within the elastic regime while strain-induced transformations occur in the post-yield regime. Both transformation variants produce easily detected signals that can be readily monitored. A review of the nature of TRIP steel materials, their properties and behavior, and the smart bolt design approach is presented with examples of the quantitative output obtained during simulated laboratory testing. A brief discussion of the detection electronics and interrogation system is provided to familiarize the audience with the technical issues encompassing this technology. Preliminary results from field testing and service experience are reviewed.

Utilizing adaptive wing technology in the control of a micro air vehicle

NASA Astrophysics Data System (ADS)

Null, William R.; Wagner, Matthew G.; Shkarayev, Sergey V.; Jouse, Wayne C.; Brock, Keith M.

2002-07-01

Evolution of the design of micro air vehicles (MAVs) towards miniaturization has been severely constrained by the size and mass of the electronic components needed to control the vehicles. Recent research, experimentation, and development in the area of smart materials have led to the possibility of embedding control actuators, fabricated from smart materials, in the wing of the vehicle, reducing both the size and mass of these components. Further advantages can be realized by developing adaptive wing structures. Small size and mass, and low airspeeds, can lead to considerable buffeting during flight, and may result in a loss of flight control. In order to counter these effects, we are developing a thin, variable-cambered airfoil design with actuators embedded within the wing. In addition to reducing the mass and size of the vehicle or, conversely, increasing its available payload, an important benefit from the adaptive wing concept is the possibility of in-flight modification of the flight envelope. Reduced airspeeds, which are crucial during loiter, can be realized by an in-flight increase in wing camber. Conversely, decreases in camber provide for an airframe best suited for rapid ingress/egress and extension of the mission range.

Intelligent Propulsion System Foundation Technology: Summary of Research

NASA Technical Reports Server (NTRS)

Williams, James C.

2004-01-01

The purpose of this cooperative agreement was to develop a foundation of intelligent propulsion technologies for NASA and industry that will have an impact on safety, noise, emissions and cost. These intelligent engine technologies included sensors, electronics, communications, control logic, actuators, and smart materials and structures. Furthermore this cooperative agreement helped prepare future graduates to develop the revolutionary intelligent propulsion technologies that will be needed to ensure pre-eminence of the U.S. aerospace industry. The program consisted of three primary research areas (and associated work elements at Ohio universities): 1.0 Turbine Engine Prognostics, 2.0 Active Controls for Emissions and Noise Reduction, and 3.0 Active Structural Controls.

High-Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement

NASA Technical Reports Server (NTRS)

Quackenbush, Todd R.; McKillip, Robert M., Jr.

2011-01-01

One of key NASA goals is to develop and integrate noise reduction technology to enable unrestricted air transportation service to all communities. One of the technical priorities of this activity has been to account for and reduce noise via propulsion/airframe interactions, identifying advanced concepts to be integrated with the airframe to mitigate these noise-producing mechanisms. An adaptive geometry chevron using embedded smart structures technology offers the possibility of maximizing engine performance while retaining and possibly enhancing the favorable noise characteristics of current designs. New high-temperature shape memory alloy (HTSMA) materials technology enables the devices to operate in both low-temperature (fan) and high-temperature (core) exhaust flows. Chevron-equipped engines have demonstrated reduced noise in testing and operational use. It is desirable to have the noise benefits of chevrons in takeoff/landing conditions, but have them deployed into a minimum drag position for cruise flight. The central feature of the innovation was building on rapidly maturing HTSMA technology to implement a next-generation aircraft noise mitigation system centered on adaptive chevron flow control surfaces. In general, SMA-actuated devices have the potential to enhance the demonstrated noise reduction effectiveness of chevron systems while eliminating the associated performance penalty. The use of structurally integrated smart devices will minimize the mechanical and subsystem complexity of this implementation. The central innovations of the effort entail the modification of prior chevron designs to include a small cut that relaxes structural stiffness without compromising the desired flow characteristics over the surface; the reorientation of SMA actuation devices to apply forces to deflect the chevron tip, exploiting this relaxed stiffness; and the use of high-temperature SMA (HTSMA) materials to enable operation in the demanding core chevron environment. The overall conclusion of these design studies was that the cut chevron concept is a critical enabling step in bringing the variable geometry core chevron within reach. The presence of the cut may be aerodynamically undesirable in some respects, but it is present only when the chevron is not immersed in the core jet exhaust. When deployed, the gap closes as the chevron tip enters the high-speed, high-temperature core stream. Aeroacoustic testing and flow visualization support the contention that this cut is inconsequential to chevron performance.

Smart Rocks for Bridge Scour Monitoring: Design and Localization Using Electromagnetic Techniques and Embedded Orientation Sensors

NASA Astrophysics Data System (ADS)

Radchenko, Andro

River bridge scour is an erosion process in which flowing water removes sediment materials (such as sand, rocks) from a bridge foundation, river beds and banks. As a result, the level of the river bed near a bridge pier is lowering such that the bridge foundation stability can be compromised, and the bridge can collapse. The scour is a dynamic process, which can accelerate rapidly during a flood event. Thus, regular monitoring of the scour progress is necessary to be performed at most river bridges. Present techniques are usually expensive, require large man/hour efforts, and often lack the real-time monitoring capabilities. In this dissertation a new method--'Smart Rocks Network for bridge scour monitoring' is introduced. The method is based on distributed wireless sensors embedded in ground underwater nearby the bridge pillars. The sensor nodes are unconstrained in movement, are equipped with years-lasting batteries and intelligent custom designed electronics, which minimizes power consumption during operation and communication. The electronic part consists of a microcontroller, communication interfaces, orientation and environment sensors (such as are accelerometer, magnetometer, temperature and pressure sensors), supporting power supplies and circuitries. Embedded in the soil nearby a bridge pillar the Smart Rocks can move/drift together with the sediments, and act as the free agent probes transmitting the unique signature signals to the base-station monitors. Individual movement of a Smart Rock can be remotely detected processing the orientation sensors reading. This can give an indication of the on-going scour progress, and set a flag for the on-site inspection. The map of the deployed Smart Rocks Network can be obtained utilizing the custom developed in-network communication protocol with signals intensity (RSSI) analysis. Particle Swarm Optimization (PSO) is applied for map reconstruction. Analysis of the map can provide detailed insight into the scour progress and topology. Smart Rocks Network wireless communication is based on the magnetoinductive (MI) link, at low (125 KHz) frequency, allowing for signal to penetrate through the water, rocks, and the bridge structure. The dissertation describes the Smart Rocks Network implementation, its electronic design and the electromagnetic/computational intelligence techniques used for the network mapping.

Distance Learning and Assistance Using Smart Glasses

ERIC Educational Resources Information Center

Spitzer, Michael; Nanic, Ibrahim; Ebner, Martin

2018-01-01

With the everyday growth of technology, new possibilities arise to support activities of everyday life. In education and training, more and more digital learning materials are emerging, but there is still room for improvement. This research study describes the implementation of a smart glasses app and infrastructure to support distance learning…

3D Printing with Nucleic Acid Adhesives

PubMed Central

2015-01-01

By relying on specific DNA:DNA interactions as a “smart glue”, we have assembled microparticles into a colloidal gel that can hold its shape. This gel can be extruded with a 3D printer to generate centimeter size objects. We show four aspects of this material: (1) The colloidal gel material holds its shape after extrusion. (2) The connectivity among the particles is controlled by the binding behavior between the surface DNA and this mediates some control over the microscale structure. (3) The use of DNA-coated microparticles dramatically reduces the cost of DNA-mediated assembly relative to conventional DNA nanotechnologies and makes this material accessible for macroscale applications. (4) This material can be assembled under biofriendly conditions and can host growing cells within its matrix. The DNA-based control over organization should provide a new means of engineering bioprinted tissues. PMID:25984570

3D Printing with Nucleic Acid Adhesives.

PubMed

Allen, Peter B; Khaing, Zin; Schmidt, Christine E; Ellington, Andrew D

2015-01-12

By relying on specific DNA:DNA interactions as a "smart glue", we have assembled microparticles into a colloidal gel that can hold its shape. This gel can be extruded with a 3D printer to generate centimeter size objects. We show four aspects of this material: (1) The colloidal gel material holds its shape after extrusion. (2) The connectivity among the particles is controlled by the binding behavior between the surface DNA and this mediates some control over the microscale structure. (3) The use of DNA-coated microparticles dramatically reduces the cost of DNA-mediated assembly relative to conventional DNA nanotechnologies and makes this material accessible for macroscale applications. (4) This material can be assembled under biofriendly conditions and can host growing cells within its matrix. The DNA-based control over organization should provide a new means of engineering bioprinted tissues.

Physics and Process Modeling (PPM) and Other Propulsion R and T. Volume 1; Materials Processing, Characterization, and Modeling; Lifting Models

NASA Technical Reports Server (NTRS)

1997-01-01

This CP contains the extended abstracts and presentation figures of 36 papers presented at the PPM and Other Propulsion R&T Conference. The focus of the research described in these presentations is on materials and structures technologies that are parts of the various projects within the NASA Aeronautics Propulsion Systems Research and Technology Base Program. These projects include Physics and Process Modeling; Smart, Green Engine; Fast, Quiet Engine; High Temperature Engine Materials Program; and Hybrid Hyperspeed Propulsion. Also presented were research results from the Rotorcraft Systems Program and work supported by the NASA Lewis Director's Discretionary Fund. Authors from NASA Lewis Research Center, industry, and universities conducted research in the following areas: material processing, material characterization, modeling, life, applied life models, design techniques, vibration control, mechanical components, and tribology. Key issues, research accomplishments, and future directions are summarized in this publication.

Smart multifunctional drug delivery towards anticancer therapy harmonized in mesoporous nanoparticles.

PubMed

Baek, Seonmi; Singh, Rajendra K; Khanal, Dipesh; Patel, Kapil D; Lee, Eun-Jung; Leong, Kam W; Chrzanowski, Wojciech; Kim, Hae-Won

2015-09-14

Nanomedicine seeks to apply nanoscale materials for the therapy and diagnosis of diseased and damaged tissues. Recent advances in nanotechnology have made a major contribution to the development of multifunctional nanomaterials, which represents a paradigm shift from single purpose to multipurpose materials. Multifunctional nanomaterials have been proposed to enable simultaneous target imaging and on-demand delivery of therapeutic agents only to the specific site. Most advanced systems are also responsive to internal or external stimuli. This approach is particularly important for highly potent drugs (e.g. chemotherapeutics), which should be delivered in a discreet manner and interact with cells/tissues only locally. Both advances in imaging and precisely controlled and localized delivery are critically important in cancer treatment, and the use of such systems - theranostics - holds great promise to minimise side effects and boost therapeutic effectiveness of the treatment. Among others, mesoporous silica nanoparticles (MSNPs) are considered one of the most promising nanomaterials for drug delivery. Due to their unique intrinsic features, including tunable porosity and size, large surface area, structural diversity, easily modifiable chemistry and suitability for functionalization, and biocompatibility, MSNPs have been extensively utilized as multifunctional nanocarrier systems. The combination or hybridization with biomolecules, drugs, and other nanoparticles potentiated the ability of MSNPs towards multifunctionality, and even smart actions stimulated by specified signals, including pH, optical signal, redox reaction, electricity and magnetism. This paper provides a comprehensive review of the state-of-the-art of multifunctional, smart drug delivery systems centered on advanced MSNPs, with special emphasis on cancer related applications.

Smart multifunctional drug delivery towards anticancer therapy harmonized in mesoporous nanoparticles

NASA Astrophysics Data System (ADS)

Baek, Seonmi; Singh, Rajendra K.; Khanal, Dipesh; Patel, Kapil D.; Lee, Eun-Jung; Leong, Kam W.; Chrzanowski, Wojciech; Kim, Hae-Won

2015-08-01

Nanomedicine seeks to apply nanoscale materials for the therapy and diagnosis of diseased and damaged tissues. Recent advances in nanotechnology have made a major contribution to the development of multifunctional nanomaterials, which represents a paradigm shift from single purpose to multipurpose materials. Multifunctional nanomaterials have been proposed to enable simultaneous target imaging and on-demand delivery of therapeutic agents only to the specific site. Most advanced systems are also responsive to internal or external stimuli. This approach is particularly important for highly potent drugs (e.g. chemotherapeutics), which should be delivered in a discreet manner and interact with cells/tissues only locally. Both advances in imaging and precisely controlled and localized delivery are critically important in cancer treatment, and the use of such systems - theranostics - holds great promise to minimise side effects and boost therapeutic effectiveness of the treatment. Among others, mesoporous silica nanoparticles (MSNPs) are considered one of the most promising nanomaterials for drug delivery. Due to their unique intrinsic features, including tunable porosity and size, large surface area, structural diversity, easily modifiable chemistry and suitability for functionalization, and biocompatibility, MSNPs have been extensively utilized as multifunctional nanocarrier systems. The combination or hybridization with biomolecules, drugs, and other nanoparticles potentiated the ability of MSNPs towards multifunctionality, and even smart actions stimulated by specified signals, including pH, optical signal, redox reaction, electricity and magnetism. This paper provides a comprehensive review of the state-of-the-art of multifunctional, smart drug delivery systems centered on advanced MSNPs, with special emphasis on cancer related applications.

Combining Sense and Intelligence for Smart Structures

NASA Technical Reports Server (NTRS)

2002-01-01

IFOS developed the I*Sense technology with assistance from a NASA Langley Research Center SBIR contract. NASA and IFOS collaborated to create sensing network designs that have high sensitivity, low power consumption, and significant potential for mass production. The joint- research effort led to the development of a module that is rugged, compact and light-weight, and immune to electromagnetic interference. These features make the I*Sense multisensor arrays favorable for smart structure applications, including smart buildings, bridges, highways, dams, power plants, ships, and oil tankers, as well as space vehicles, space stations, and other space structures. For instance, the system can be used as an early warning and detection device, with alarms being set to monitor the maximum allowable strain and stress values at various points of a given structure.

Numerical modeling and model updating for smart laminated structures with viscoelastic damping

NASA Astrophysics Data System (ADS)

Lu, Jun; Zhan, Zhenfei; Liu, Xu; Wang, Pan

2018-07-01

This paper presents a numerical modeling method combined with model updating techniques for the analysis of smart laminated structures with viscoelastic damping. Starting with finite element formulation, the dynamics model with piezoelectric actuators is derived based on the constitutive law of the multilayer plate structure. The frequency-dependent characteristics of the viscoelastic core are represented utilizing the anelastic displacement fields (ADF) parametric model in the time domain. The analytical model is validated experimentally and used to analyze the influencing factors of kinetic parameters under parametric variations. Emphasis is placed upon model updating for smart laminated structures to improve the accuracy of the numerical model. Key design variables are selected through the smoothing spline ANOVA statistical technique to mitigate the computational cost. This updating strategy not only corrects the natural frequencies but also improves the accuracy of damping prediction. The effectiveness of the approach is examined through an application problem of a smart laminated plate. It is shown that a good consistency can be achieved between updated results and measurements. The proposed method is computationally efficient.

Full-Scale Prestress Loss Monitoring of Damaged RC Structures Using Distributed Optical Fiber Sensing Technology

PubMed Central

Lan, Chunguang; Zhou, Zhi; Ou, Jinping

2012-01-01

For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA) sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC) beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams. PMID:22778590

Full-scale prestress loss monitoring of damaged RC structures using distributed optical fiber sensing technology.

PubMed

Lan, Chunguang; Zhou, Zhi; Ou, Jinping

2012-01-01

For the safety of prestressed structures, prestress loss is a critical issue that will increase with structural damage, so it is necessary to investigate prestress loss of prestressed structures under different damage scenarios. Unfortunately, to date, no qualified techniques are available due to difficulty for sensors to survive in harsh construction environments of long service life and large span. In this paper, a novel smart steel strand based on the Brillouin optical time domain analysis (BOTDA) sensing technique was designed and manufactured, and then series of tests were used to characterize properties of the smart steel strands. Based on prestress loss principle analysis of damaged structures, laboratory tests of two similar beams with different damages were used to verify the concept of full-scale prestress loss monitoring of damaged reinforced concrete (RC) beams by using the smart steel strands. The prestress losses obtained from the Brillouin sensors are compared with that from conventional sensors, which provided the evolution law of prestress losses of damaged RC beams. The monitoring results from the proposed smart strand can reveal both spatial distribution and time history of prestress losses of damaged RC beams.

A Cs(x)WO3/ZnO nanocomposite as a smart coating for photocatalytic environmental cleanup and heat insulation.

PubMed

Wu, Xiaoyong; Yin, Shu; Xue, Dongfeng; Komarneni, Sridhar; Sato, Tsugio

2015-10-28

A novel CsxWO3/ZnO smart coating was proposed to achieve multiple functions, such as heat insulation, photodecomposition of toxic NO gas, blocking of harmful UV light, etc. In this composite coating, CsxWO3 nanorods were used as a NIR and UV light shielding material while ZnO nanoparticles were utilized as a photocatalyst and a material to enhance visible light transmittance and block UV light. When the mass ratio of CsxWO3/ZnO was 1, the composite coating possessed a very good visible light transmittance of over 80% and an excellent UV-shielding ability. This novel coating showed heat insulation that is superior to the ITO coating and photocatalytic decontamination of NO gas that is superior to the standard TiO2 (P25). The proposed CsxWO3/ZnO smart coating is a promising material not only for energy saving but also for environmental cleanup.

Launch vehicle flight control augmentation using smart materials and advanced composites (CDDF Project 93-05)

NASA Technical Reports Server (NTRS)

Barret, C.

1995-01-01

The Marshall Space Flight Center has a rich heritage of launch vehicles that have used aerodynamic surfaces for flight stability such as the Saturn vehicles and flight control such as on the Redstone. Recently, due to aft center-of-gravity locations on launch vehicles currently being studied, the need has arisen for the vehicle control augmentation that is provided by these flight controls. Aerodynamic flight control can also reduce engine gimbaling requirements, provide actuator failure protection, enhance crew safety, and increase vehicle reliability, and payload capability. In the Saturn era, NASA went to the Moon with 300 sq ft of aerodynamic surfaces on the Saturn V. Since those days, the wealth of smart materials and advanced composites that have been developed allow for the design of very lightweight, strong, and innovative launch vehicle flight control surfaces. This paper presents an overview of the advanced composites and smart materials that are directly applicable to launch vehicle control surfaces.

Multiscale modeling of PVDF matrix carbon fiber composites

NASA Astrophysics Data System (ADS)

Greminger, Michael; Haghiashtiani, Ghazaleh

2017-06-01

Self-sensing carbon fiber reinforced composites have the potential to enable structural health monitoring that is inherent to the composite material rather than requiring external or embedded sensors. It has been demonstrated that a self-sensing carbon fiber reinforced polymer composite can be created by using the piezoelectric polymer polyvinylidene difluoride (PVDF) as the matrix material and using a Kevlar layer to separate two carbon fiber layers. In this configuration, the electrically conductive carbon fiber layers act as electrodes and the Kevlar layer acts as a dielectric to prevent the electrical shorting of the carbon fiber layers. This composite material has been characterized experimentally for its effective d 33 and d 31 piezoelectric coefficients. However, for design purposes, it is desirable to obtain a predictive model of the effective piezoelectric coefficients for the final smart composite material. Also, the inverse problem can be solved to determine the degree of polarization obtained in the PVDF material during polarization by comparing the effective d 33 and d 31 values obtained in experiment to those predicted by the finite element model. In this study, a multiscale micromechanics and coupled piezoelectric-mechanical finite element modeling approach is introduced to predict the mechanical and piezoelectric performance of a plain weave carbon fiber reinforced PVDF composite. The modeling results show good agreement with the experimental results for the mechanical and electrical properties of the composite. In addition, the degree of polarization of the PVDF component of the composite is predicted using this multiscale modeling approach and shows that there is opportunity to drastically improve the smart composite’s performance by improving the polarization procedure.

Hadoop Oriented Smart Cities Architecture.

PubMed

Diaconita, Vlad; Bologa, Ana-Ramona; Bologa, Razvan

2018-04-12

A smart city implies a consistent use of technology for the benefit of the community. As the city develops over time, components and subsystems such as smart grids, smart water management, smart traffic and transportation systems, smart waste management systems, smart security systems, or e-governance are added. These components ingest and generate a multitude of structured, semi-structured or unstructured data that may be processed using a variety of algorithms in batches, micro batches or in real-time. The ICT architecture must be able to handle the increased storage and processing needs. When vertical scaling is no longer a viable solution, Hadoop can offer efficient linear horizontal scaling, solving storage, processing, and data analyses problems in many ways. This enables architects and developers to choose a stack according to their needs and skill-levels. In this paper, we propose a Hadoop-based architectural stack that can provide the ICT backbone for efficiently managing a smart city. On the one hand, Hadoop, together with Spark and the plethora of NoSQL databases and accompanying Apache projects, is a mature ecosystem. This is one of the reasons why it is an attractive option for a Smart City architecture. On the other hand, it is also very dynamic; things can change very quickly, and many new frameworks, products and options continue to emerge as others decline. To construct an optimized, modern architecture, we discuss and compare various products and engines based on a process that takes into consideration how the products perform and scale, as well as the reusability of the code, innovations, features, and support and interest in online communities.

Hadoop Oriented Smart Cities Architecture

PubMed Central

Bologa, Ana-Ramona; Bologa, Razvan

2018-01-01

A smart city implies a consistent use of technology for the benefit of the community. As the city develops over time, components and subsystems such as smart grids, smart water management, smart traffic and transportation systems, smart waste management systems, smart security systems, or e-governance are added. These components ingest and generate a multitude of structured, semi-structured or unstructured data that may be processed using a variety of algorithms in batches, micro batches or in real-time. The ICT architecture must be able to handle the increased storage and processing needs. When vertical scaling is no longer a viable solution, Hadoop can offer efficient linear horizontal scaling, solving storage, processing, and data analyses problems in many ways. This enables architects and developers to choose a stack according to their needs and skill-levels. In this paper, we propose a Hadoop-based architectural stack that can provide the ICT backbone for efficiently managing a smart city. On the one hand, Hadoop, together with Spark and the plethora of NoSQL databases and accompanying Apache projects, is a mature ecosystem. This is one of the reasons why it is an attractive option for a Smart City architecture. On the other hand, it is also very dynamic; things can change very quickly, and many new frameworks, products and options continue to emerge as others decline. To construct an optimized, modern architecture, we discuss and compare various products and engines based on a process that takes into consideration how the products perform and scale, as well as the reusability of the code, innovations, features, and support and interest in online communities. PMID:29649172

4D Origami by Smart Embroidery.

PubMed

Stoychev, Georgi; Razavi, Mir Jalil; Wang, Xianqiao; Ionov, Leonid

2017-09-01

There exist many methods for processing of materials: extrusion, injection molding, fibers spinning, 3D printing, to name a few. In most cases, materials with a static, fixed shape are produced. However, numerous advanced applications require customized elements with reconfigurable shape. The few available techniques capable of overcoming this problem are expensive and/or time-consuming. Here, the use of one of the most ancient technologies for structuring, embroidering, is proposed to generate sophisticated patterns of active materials, and, in this way, to achieve complex actuation. By combining experiments and computational modeling, the fundamental rules that can predict the folding behavior of sheets with a variety of stitch-patterns are elucidated. It is demonstrated that theoretical mechanics analysis is only suitable to predict the behavior of the simplest experimental setups, whereas computer modeling gives better predictions for more complex cases. Finally, the applicability of the rules by designing basic origami structures and wrinkling substrates with controlled thermal insulation properties is shown. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-field coupled sensing network for health monitoring of composite bolted joint

NASA Astrophysics Data System (ADS)

Wang, Yishou; Qing, Xinlin; Dong, Liang; Banerjee, Sourav

2016-04-01

Advanced fiber reinforced composite materials are becoming the main structural materials of next generation of aircraft because of their high strength and stiffness to weight ratios, and excellent designability. As key components of large composite structures, joints play important roles to ensure the integrity of the composite structures. However, it is very difficult to analyze the strength and failure modes of composite joints due to their complex nonlinear coupling factors. Therefore, there is a need to monitor, diagnose, evaluate and predict the structure state of composite joints. This paper proposes a multi-field coupled sensing network for health monitoring of composite bolted joints. Major work of this paper includes: 1) The concept of multifunctional sensor layer integrated with eddy current sensors, Rogowski coil and arrayed piezoelectric sensors; 2) Development of the process for integrating the eddy current sensor foil, Rogowski coil and piezoelectric sensor array in multifunctional sensor layer; 3) A new concept of smart composite joint with multifunctional sensing capability. The challenges for building such a structural state sensing system and some solutions to address the challenges are also discussed in the study.

Bending continuous structures with SMAs: a novel robotic fish design.

PubMed

Rossi, C; Colorado, J; Coral, W; Barrientos, A

2011-12-01

In this paper, we describe our research on bio-inspired locomotion systems using deformable structures and smart materials, concretely shape memory alloys (SMAs). These types of materials allow us to explore the possibility of building motor-less and gear-less robots. A swimming underwater fish-like robot has been developed whose movements are generated using SMAs. These actuators are suitable for bending the continuous backbone of the fish, which in turn causes a change in the curvature of the body. This type of structural arrangement is inspired by fish red muscles, which are mainly recruited during steady swimming for the bending of a flexible but nearly incompressible structure such as the fishbone. This paper reviews the design process of these bio-inspired structures, from the motivations and physiological inspiration to the mechatronics design, control and simulations, leading to actual experimental trials and results. The focus of this work is to present the mechanisms by which standard swimming patterns can be reproduced with the proposed design. Moreover, the performance of the SMA-based actuators' control in terms of actuation speed and position accuracy is also addressed.

Potential Applications of Smart Multifunctional Wearable Materials to Gerontology.

PubMed

Armstrong, David G; Najafi, Bijan; Shahinpoor, Mohsen

2017-01-01

Smart multifunctional materials can play a constructive role in addressing some very important aging-related issues. Aging affects the ability of older adults to continue to live safely and economically in their own residences for as long as possible. Thus, there will be a greater need for preventive, acute, rehabilitative, and long-term health care services for older adults as well as a need for tools to enable them to function independently during daily activities. The objective of this paper is, thus, to present a comprehensive review of some potential smart materials and their areas of applications to gerontology. Thus, brief descriptions of various currently available multifunctional smart materials and their possible applications to aging-related problems are presented. It is concluded that some of the most important applications to geriatrics may be in various sensing scenarios to collect health-related feedback or information and provide personalized care. Further described are the applications of wearable technologies to aging-related needs, including devices for home rehabilitation, remote monitoring, social well-being, frailty monitoring, monitoring of diabetes and wound healing and fall detection or prediction. It is also concluded that wearable technologies, when combined with an appropriate application and with appropriate feedback, may help improve activities and functions of older patients with chronic diseases. Finally, it is noted that methods developed to measure what one collectively manages in this population may provide a foundation to establish new definitions of quality of life. © 2017 S. Karger AG, Basel.

ScienceCast 125: Genius Materials on the ISS

NASA Image and Video Library

2013-11-25

Researchers working with magnetic fluids on the International Space Station are taking "smart materials" to the next level. With proper coaxing, molecules can assemble themselves into "genius materials" with surprising properties.

Smart guidewires for smooth navigation in neurovascular intervention

NASA Astrophysics Data System (ADS)

Chen, Yanfei; Barry, Matthew M.; Shayan, Mahdis; Jankowitz, Brian T.; Duan, Xinjie; Robertson, Anne M.; Chyu, Minking K.; Chun, Youngjae

2015-04-01

A smart guidewire using nitinol materials was designed, manufactured and evaluated the device functionality, such as bending performance, trackability, thermal effects, and thrombogenic response. Two types of nitinol material were partially used to enhance the guidewire trackability. A proposed smart guidewire system uses either one- or two-way shape-memory alloy nitinol (1W-SMA, 2W-SMA) wires (0.015, 381µm nitinol wire). Bending stiffness was measured using in vitro test system, which contains the NI USB-9162 data logger and LabView Signal Express 2010. Temperature distribution and displacement were evaluated via recording a 60Hz movie using a SC325 camera. Hemocompatibility was evaluated by scanning electron microscopy after one heating cycle of nitinol under the Na-citrate porcine whole blood circulation. A smart guidewire showed 30 degrees bending after applying or disconnecting electrical current. While the temperature of the nitinol wires increased more than 70 °C, the surrounding temperature with the commercially available catheter coverings showed below human body temperature showing 30 ̴ 33 °C. There was no significant platelet attachment or blood coagulation when the guidewire operates. Novel smart guidewires have been developed using shape memory alloy nitinol, which may represent a novel alternative to typical commercially available guidewires for interventional procedures.

Buckling analysis of SMA bonded sandwich structure – using FEM

NASA Astrophysics Data System (ADS)

Katariya, Pankaj V.; Das, Arijit; Panda, Subrata K.

2018-03-01

Thermal buckling strength of smart sandwich composite structure (bonded with shape memory alloy; SMA) examined numerically via a higher-order finite element model in association with marching technique. The excess geometrical distortion of the structure under the elevated environment modeled through Green’s strain function whereas the material nonlinearity counted with the help of marching method. The system responses are computed numerically by solving the generalized eigenvalue equations via a customized MATLAB code. The comprehensive behaviour of the current finite element solutions (minimum buckling load parameter) is established by solving the adequate number of numerical examples including the given input parameter. The current numerical model is extended further to check the influence of various structural parameter of the sandwich panel on the buckling temperature including the SMA effect and reported in details.

Processing of Ni30Pt20Ti50 High-Temperature Shape-Memory Alloy Into Thin Rod Demonstrated

NASA Technical Reports Server (NTRS)

Noebe, Ronald D.; Draper, Susan L.; Biles, Tiffany A.; Leonhardt, Todd

2005-01-01

High-temperature shape-memory alloys (HTSMAs) based on nickel-titanium (NiTi) with significant ternary additions of palladium (Pd), platinum (Pt), gold (Au), or hafnium (Hf) have been identified as potential high-temperature actuator materials for use up to 500 C. These materials provide an enabling technology for the development of "smart structures" used to control the noise, emissions, or efficiency of gas turbine engines. The demand for these high-temperature versions of conventional shape-memory alloys also has been growing in the automotive, process control, and energy industries. However these materials, including the NiPtTi alloys being developed at the NASA Glenn Research Center, will never find widespread acceptance unless they can be readily processed into useable forms.

Active Blade Vibration Control Being Developed and Tested

NASA Technical Reports Server (NTRS)

Johnson, Dexter

2003-01-01

Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

Smart Point Cloud: Definition and Remaining Challenges

NASA Astrophysics Data System (ADS)

Poux, F.; Hallot, P.; Neuville, R.; Billen, R.

2016-10-01

Dealing with coloured point cloud acquired from terrestrial laser scanner, this paper identifies remaining challenges for a new data structure: the smart point cloud. This concept arises with the statement that massive and discretized spatial information from active remote sensing technology is often underused due to data mining limitations. The generalisation of point cloud data associated with the heterogeneity and temporality of such datasets is the main issue regarding structure, segmentation, classification, and interaction for an immediate understanding. We propose to use both point cloud properties and human knowledge through machine learning to rapidly extract pertinent information, using user-centered information (smart data) rather than raw data. A review of feature detection, machine learning frameworks and database systems indexed both for mining queries and data visualisation is studied. Based on existing approaches, we propose a new 3-block flexible framework around device expertise, analytic expertise and domain base reflexion. This contribution serves as the first step for the realisation of a comprehensive smart point cloud data structure.

Coupling carbon nanomaterials with photochromic molecules for the generation of optically responsive materials

PubMed Central

Zhang, Xiaoyan; Hou, Lili; Samorì, Paolo

2016-01-01

Multifunctional carbon-based nanomaterials offer routes towards the realization of smart and high-performing (opto)electronic (nano)devices, sensors and logic gates. Meanwhile photochromic molecules exhibit reversible transformation between two forms, induced by the absorption of electromagnetic radiation. By combining carbon-based nanomaterials with photochromic molecules, one can achieve reversible changes in geometrical structure, electronic properties and nanoscale mechanics triggering by light. This thus enables a reversible modulation of numerous physical and chemical properties of the carbon-based nanomaterials towards the fabrication of cognitive devices. This review examines the state of the art with respect to these responsive materials, and seeks to identify future directions for investigation. PMID:27067387

Green piezoelectric for autonomous smart textile

NASA Astrophysics Data System (ADS)

Lemaire, E.; Borsa, C. J.; Briand, D.

2015-12-01

In this work, the fabrication of Rochelle salt based piezoelectric textiles are shown. Structures composed of fibers and Rochelle salt are easily produced using green processes. Both manufacturing and the material itself are really efficient in terms of environmental impact, considering the fabrication processes and the material resources involved. Additionally Rochelle salt is biocompatible. In this green paradigm, active sensing or actuating textiles are developed. Thus processing method and piezoelectric properties have been studied: (1) pure crystals are used as acoustic actuator, (2) fabrication of the textile-based composite is detailed, (3) converse effective d33 is evaluated and compared to lead zirconate titanate ceramic. The utility of textile-based piezoelectric merits its use in a wide array of applications.

An Active Smart Material Control System for F/A-18 Buffet Alleviation

NASA Technical Reports Server (NTRS)

Sheta, Essam F.; Moses, Robert W.; Huttsell, Lawrence J.; Harrand, Vincent J.

2003-01-01

The vertical tail buffet problem of fighter aircraft occurs at high angles of attack when the vortical flow breaks down ahead of the vertical tails resulting in unsteady and unbalanced pressure loads on the vertical tails. The buffet loads imposed upon the vertical tails resulted in a premature fatigue failure of the tails, and consequently limits the performance and super maneuverability of twin-tail fighter aircraft. An active smart material control system using distributed piezoelectric actuators has been developed for buffet alleviation and is presented. The inboard and outboard surfaces of the vertical tail are equipped with piezoelectric actuators to control the buffet responses in the first bending and torsion modes. The electrodynamics of the piezoelectric actuators are expressed with a three-dimensional finite-element model. A single-input-single-output controller is designed to drive the active piezoelectric actuators. High-fidelity multidisciplinary analysis modules for the fluid dynamics, structure dynamics, electrodynamics of the piezoelectric actuators, control law, fluid structure interfacing, and grid motion are integrated into a multidisciplinary computing environment that controls the temporal synchronization of the analysis modules. At 30 degree angle of attack, RMS values of tip acceleration are reduced by as much as 12%. The peak values of the power spectral density of tail-tip acceleration are reduced by as much as 22% in the first bending mode and by as much as 82% in the first torsion mode. The actively controlled piezoelectric actuators were also effective in adding damping at wide range of angles of attack.

Embedding of Superelastic SMA Wires into Composite Structures: Evaluation of Impact Properties

NASA Astrophysics Data System (ADS)

Pappadà, Silvio; Rametta, Rocco; Toia, Luca; Coda, Alberto; Fumagalli, Luca; Maffezzoli, Alfonso

2009-08-01

Shape memory alloy (SMA) represents the most versatile way to realize smart materials with sensing, controlling, and actuating functions. Due to their unique mechanical and thermodynamic properties and to the possibility to obtain SMA wires with very small diameters, they are used as smart components embedded into the conventional resins or composites, obtaining active abilities, tunable properties, self-healing properties, and damping capacity. Moreover, superelastic SMAs are used to increase the impact resistance properties of composite materials. In this study, the influence of the integration of thin superelastic wires to suppress propagating damage of composite structures has been investigated. Superelastic SMAs have very high strain to failure and recoverable elastic strain, due to a stress-induced martensitic phase transition creating a plateau region in the stress-strain curve. NiTi superelastic wires ( A f = -15 °C fully annealed) of 0.10 mm in diameter have been produced and characterized by SAES Getters. The straight annealed wire shows the typical flag stress-strain behavior. The measured loading plateau is about 450 MPa at ambient temperature with a recoverable elastic strain of more than 6%. For these reasons superelastic SMA fibers can absorb much more strain energy than other fibers before their failure, partly with a constant stress level. In this paper, the improvement of composite laminates impact properties by embedding SMA wires is evaluated and indications for design and manufacturing of SMA composites with high-impact properties are also given.

Workshop report: US-China workshop on smart structures and smart systems

NASA Astrophysics Data System (ADS)

Tomizuka, Masayoshi

2006-03-01

A Joint U.S.-China workshop on the topic of Integrated Sensing Systems, Mechatronics and Smart Structures Technologies was held in Jinan, China in October 2005 to evaluate the current status of research and education in the topic areas in the United States and China, to identify critical and strategic research and educational issues of mutual interest, and to identify joint research projects and potential research teams for collaborative research activities. The workshop included a series of presentations by leading researchers and educators from the United States and China and group discussions on the workshop objectives.

Magnetic field angle dependent hysteresis of a magnetorheological suspension

NASA Astrophysics Data System (ADS)

Dohmen, Eike; Borin, Dmitry; Zubarev, Andrey

2017-12-01

Magnetorheological (MR) materials are of growing interest for a development and realisation of adaptive components and damping devices. The influence of the magnetic field orientation on the rheological properties of smart materials like MR fluids or magnetic hybrid composites is a key aspect which still is not fully understood, but occurs in almost every real life MR application. To cope with the practical needs and efficiently utilise these smart materials while taking into account their material phenomena experimentally validated practice-oriented models are needed. The authors use a coupled phenomenological approach to adjust and discuss a developed theoretical model based on experimentally obtained data. In addition the data helps to get a better understanding of internal processes and interrelations in MR suspensions.

"Fool Me Once, Shame on You; Fool Me Twice, Shame on Me": African American Students' Reclamation of Smartness as Resistance

ERIC Educational Resources Information Center

Twyman Hoff, Pamela

2016-01-01

In African American culture competing value systems shape the definition and value of smartness. This article will explore African American "sayins" as a tool to transmit the counter-hegemonic cultural value of smartness. "Sayins," a facet of the African American oral tradition, are drawn from the deep structures of African…

Engineered Living Materials: Prospects and Challenges for Using Biological Systems to Direct the Assembly of Smart Materials.

PubMed

Nguyen, Peter Q; Courchesne, Noémie-Manuelle Dorval; Duraj-Thatte, Anna; Praveschotinunt, Pichet; Joshi, Neel S

2018-05-01

Vast potential exists for the development of novel, engineered platforms that manipulate biology for the production of programmed advanced materials. Such systems would possess the autonomous, adaptive, and self-healing characteristics of living organisms, but would be engineered with the goal of assembling bulk materials with designer physicochemical or mechanical properties, across multiple length scales. Early efforts toward such engineered living materials (ELMs) are reviewed here, with an emphasis on engineered bacterial systems, living composite materials which integrate inorganic components, successful examples of large-scale implementation, and production methods. In addition, a conceptual exploration of the fundamental criteria of ELM technology and its future challenges is presented. Cradled within the rich intersection of synthetic biology and self-assembling materials, the development of ELM technologies allows the power of biology to be leveraged to grow complex structures and objects using a palette of bio-nanomaterials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-voltage tunable color in full visible region using ferroelectric liquid-crystal-doped cholesteric liquid-crystal smart materials

NASA Astrophysics Data System (ADS)

Lin, Jia-De; Lin, Jyun-Wei; Lee, Chia-Rong

2018-02-01

Electrical tuning of photonic bandgap (PBG) of cholesteric liquid crystal (CLC) without deformation within the entire visible region at low voltages is not easy to achieve. This study demonstrates low-voltage-tunable PBG in full visible region with less deformation of the PBG based on smart materials of ferroelectric liquid crystal doped CLC (FLC-CLC) integrating with electrothermal film heaters. Experimental results show that the reflective color of the FLC-CLC can be low-voltage-tuned through entire visible region. The induced temperature change is induced by electrically heating the electrothermal film heaters at low voltages at near the smectic-CLC transition temperature. Coaxial electrospinning can be used to develop smart fibrous devices with FLC/CLC-core and polymer-shell which color is tunable in full visible region at low voltages.

Smart glove: hand master using magnetorheological fluid actuators

NASA Astrophysics Data System (ADS)

Nam, Y. J.; Park, M. K.; Yamane, R.

2007-12-01

In this study, a hand master using five miniature magneto-rheological (MR) actuators, which is called 'the smart glove', is introduced. This hand master is intended to display haptic feedback to the fingertip of the human user interacting with any virtual objects in virtual environment. For the smart glove, two effective approaches are proposed: (i) by using the MR actuator which can be considered as a passive actuator, the smart glove is made simple in structure, high in power, low in inertia, safe in interface and stable in haptic feedback, and (ii) with a novel flexible link mechanism designed for the position-force transmission between the fingertips and the actuators, the number of the actuator and the weight of the smart glove can be reduced. These features lead to the improvement in the manipulability and portability of the smart glove. The feasibility of the constructed smart glove is verified through basic performance evaluation.

Parametric analysis and temperature effect of deployable hinged shells using shape memory polymers

NASA Astrophysics Data System (ADS)

Tao, Ran; Yang, Qing-Sheng; He, Xiao-Qiao; Liew, Kim-Meow

2016-11-01

Shape memory polymers (SMPs) are a class of intelligent materials, which are defined by their capacity to store a temporary shape and recover an original shape. In this work, the shape memory effect of SMP deployable hinged shell is simulated by using compiled user defined material subroutine (UMAT) subroutine of ABAQUS. Variations of bending moment and strain energy of the hinged shells with different temperatures and structural parameters in the loading process are given. The effects of the parameters and temperature on the nonlinear deformation process are emphasized. The entire thermodynamic cycle of SMP deployable hinged shell includes loading at high temperature, load carrying with cooling, unloading at low temperature and recovering the original shape with heating. The results show that the complicated thermo-mechanical deformation and shape memory effect of SMP deployable hinge are influenced by the structural parameters and temperature. The design ability of SMP smart hinged structures in practical application is prospected.

Development of a low-cost x-ray mask for high-aspect-ratio MEM smart structures

NASA Astrophysics Data System (ADS)

Ajmera, Pratul K.; Stadler, Stefan; Abdollahi, Neda

1998-07-01

A cost-effective process with short fabrication time for making x-ray masks for research and development purposes is described here for fabricating high-aspect ratio microelectromechanical structures using synchrotron based x- ray lithography. Microscope cover glass slides as membrane material is described. Slides with an initial thickness of 175 micrometers are etched to a thickness in the range of 10 - 25 micrometers using a diluted HF and buffered hydrofluoric acid solutions. The thinned slides are glued on supportive mask frames and sputtered with a chromium/silver sandwich layer which acts as a plating base layer for the deposition of the gold absorber. The judicial choice of glue and mask frame material are significant parameters in a successful fabrication process. Gold absorber structures are electroplated on the membrane. Calculations are done for contrast and dose ratio obtained in the photoresist after synchrotron radiation as a function of the mask design parameters. Exposure experiments are performed to prove the applicability of the fabricated x-ray mask.

Smart Structures for Vibration Control on Long-Term Space Exploration and Habitation Missions

NASA Technical Reports Server (NTRS)

Gattis, Christy B.; Shepard, W. Steve, Jr.

2004-01-01

The current vision for space exploration focuses on human missions to the Moon, Mars, and beyond. To support these goals, it is certain that new vehicles and intermediate bases will be developed, whether that means simply re-direction of the ISS as a "mission research facility" or construction of a lunar base. Since these facilities are expected to be constructed from inherently light-weight materials, this work examines some of the potential sources of vibration and noise as well as means for controlling these vibrations. Many of the operating components within these facilities, such as pumps, fans, and motors, will produce vibrations during operation. These vibrations become structure in which they are housed. Resonances can impact acoustic noise levels and noise quality within the environment, possibly affecting crew health and productivity. For long-term missions in particular, it is expected that crew members will spend significant portions of their time restrained in the structure, such as in seats. As a result, the general health and well-being of the crew can be improved by limiting the harmful effects of human exposure to long-term audible and tactile vibration input. Besides the human factor, this work also examines some operational considerations in which vibrations play an important role. Vibrations can impact the environment for science and in-situ manufacturing research within these vehicles. Since a benign vibratory environment is beneficial for most types of science experiments, there is a need for various forms of vibration control. Because the operational characteristics of a vehicle can change during a long-term mission, it is further expected that the characteristics of many of the vibratory excitations will change with time. Consequently, the form of vibration control needed to improve overall habitability and usefulness of the vehicle or element for exploration missions will rely to some degree on the vibration control system's ability to adapt. To address these needs, this work also examines the development and use of smart materials to tune the dynamic characteristics of the structure in a passive sense. One prime example is the use of an adaptive electrical shunt connected to a piezoelectric patch in order to provide tuned passive vibration damping. The work also examines the use of active vibration control, such as by applying power to that same piezoelectric patch. The overall goal is to examine the use of smart structures that can react to the environment thereby improving the overall living, working, and learning environment for these long-term missions.

Study of interface influence on bending performance of CFRP with embedded optical fibers

NASA Astrophysics Data System (ADS)

Liu, Rong-mei; Liang, Da-kai

2008-11-01

Studies showed that the bending strength of composite would be affected by embedded optical fibers. Interface strength between the embedded optical fiber and the matrix was studied in this paper. Based on the single fiber pull out tests, the interfacial shear strength between the coating and the clad is the weakest. The shear strength of the optical fiber used in this study is near to 0.8MPa. In order to study the interfacial effect on bending property of generic smart structure, a quasi-isotropic composite laminates were produced from Toray T300C/ epoxy prepreg. Optical fibers were embedded within different orientation plies of the plates, with the optical fibers embedded in the same direction. Accordingly, five different types of plates were produced. Impact tests were carried out on the 5 different plate types. It is shown that when the fiber was embedded at the upper layer, the bending strength drops mostly. The bending normal stress on material arrives at the maximum. So does the normal stress applied on the optical fiber at the surface. Therefore, destructions could originate at the interface between the coating and the clad foremost. The ultimate strength of the smart structure will be affected furthest.

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning.

PubMed

Sivakumaran, Daryl; Bakaic, Emilia; Campbell, Scott B; Xu, Fei; Mueller, Eva; Hoare, Todd

2018-04-16

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veedu, Vinod; Hadmack, Michael; Pollock, Jacob

Nanite™ is a cementitious material that contains a proprietary formulation of functionalized nanomaterial additive to transform conventional cement into a smart material responsive to pressure (or stress), temperature, and any intrinsic changes in composition. This project has identified optimal sensing modalities of smart well cement and demonstrated how real-time sensing of Nanite™ can improve long-term wellbore integrity and zonal isolation in shale gas and applicable oil and gas operations. Oceanit has explored Nanite’s electrical sensing properties in depth and has advanced the technology from laboratory proof-of-concept to sub-scale testing in preparation for field trials.

Non-Target Screening of Veterinary Drugs Using Tandem Mass Spectrometry on SmartMass

NASA Astrophysics Data System (ADS)

Xia, Bing; Liu, Xin; Gu, Yu-Cheng; Zhang, Zhao-Hui; Wang, Hai-Yan; Ding, Li-Sheng; Zhou, Yan

2013-05-01

Non-target screening of veterinary drugs using tandem mass spectrometric data was performed on the SmartMass platform. This newly developed software uses the characteristic fragmentation patterns (CFP) to identify chemicals, especially those containing particular substructures. A mixture of 17 sulfonamides was separated by ultra performance liquid chromatography (UPLC), and SmartMass was used to process the tandem mass spectrometry (MS/MS) data acquired on an Orbitrap mass spectrometer. The data were automatically extracted, and each sulfonamide was recognized and analyzed with a prebuilt analysis rule. By using this software, over 98 % of the false candidate structures were eliminated, and all the correct structures were found within the top 10 of the ranking lists. Furthermore, SmartMass could also be used to identify slightly modified contraband drugs and metabolites with simple prebuilt rules. [Figure not available: see fulltext.

Distributed ice accretion sensor for smart aircraft structures

NASA Technical Reports Server (NTRS)

Gerardi, J. J.; Hickman, G. A.

1989-01-01

A distributed ice accretion sensor is presented, based on the concept of smart structures. Ice accretion is determined using spectral techniques to process signals from piezoelectric sensors integral to the airfoil skin. Frequency shifts in the leading edge structural skin modes are correlated to ice thickness. It is suggested that this method may be used to detect ice over large areas with minimal hardware. Results are presented from preliminary tests to measure simulated ice growth.

Flexible Lithium-Ion Batteries with High Areal Capacity Enabled by Smart Conductive Textiles.

PubMed

Ha, Sung Hoon; Shin, Kyu Hang; Park, Hae Won; Lee, Yun Jung

2018-02-05

Increasing demand for flexible devices in various applications, such as smart watches, healthcare, and military applications, requires the development of flexible energy-storage devices, such as lithium-ion batteries (LIBs) with high flexibility and capacity. However, it is difficult to ensure high capacity and high flexibility simultaneously through conventional electrode preparation processes. Herein, smart conductive textiles are employed as current collectors for flexible LIBs owing to their inherent flexibility, fibrous network, rough surface for better adhesion, and electrical conductivity. Conductivity and flexibility are further enhanced by nanosizing lithium titanate oxide (LTO) and lithium iron phosphate (LFP) active materials, and hybridizing them with a flexible 2D graphene template. The resulting LTO/LFP full cells demonstrate high areal capacity and flexibility with tolerance to mechanical fatigue. The battery achieves a capacity of 1.2 mA h cm -2 while showing excellent flexibility. The cells demonstrate stable open circuit voltage retention under repeated flexing for 1000 times at a bending radius of 10 mm. The discharge capacity of the unflexed battery is retained in cells subjected to bending for 100 times at bending radii of 30, 20, and 10 mm, respectively, confirming that the suggested electrode configuration successfully prevents structural damage (delamination or cracking) upon repeated deformation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Constructing Repairable Meta-Structures of Ultra-Broad-Band Electromagnetic Absorption from Three-Dimensional Printed Patterned Shells.

PubMed

Song, Wei-Li; Zhou, Zhili; Wang, Li-Chen; Cheng, Xiao-Dong; Chen, Mingji; He, Rujie; Chen, Haosen; Yang, Yazheng; Fang, Daining

2017-12-13

Ultra-broad-band electromagnetic absorption materials and structures are increasingly attractive for their critical role in competing with the advanced broad-band electromagnetic detection systems. Mechanically soft and weak wax-based materials composites are known to be insufficient to serve in practical electromagnetic absorption applications. To break through such barriers, here we developed an innovative strategy to enable the wax-based composites to be robust and repairable meta-structures by employing a three-dimensional (3D) printed polymeric patterned shell. Because of the integrated merits from both the dielectric loss wax-based composites and mechanically robust 3D printed shells, the as-fabricated meta-structures enable bear mechanical collision and compression, coupled with ultra-broad-band absorption (7-40 and 75-110 GHz, reflection loss  smaller than -10 dB) approaching state-of-the-art electromagnetic absorption materials. With the assistance of experiment and simulation methods, the design advantages and mechanism of employing such 3D printed shells for substantially promoting the electromagnetic absorption performance have been demonstrated. Therefore, such universal strategy that could be widely extended to other categories of wax-based composites highlights a smart stage on which high-performance practical multifunction meta-structures with ultra-broad-band electromagnetic absorption could be envisaged.

Magnetic Field Triggered Multicycle Damage Sensing and Self Healing.

PubMed

Ahmed, Anansa S; Ramanujan, R V

2015-09-08

Multifunctional materials inspired by biological structures have attracted great interest, e.g. for wearable/ flexible "skin" and smart coatings. A current challenge in this area is to develop an artificial material which mimics biological skin by simultaneously displaying color change on damage as well as self healing of the damaged region. Here we report, for the first time, the development of a damage sensing and self healing magnet-polymer composite (Magpol), which actively responds to an external magnetic field. We incorporated reversible sensing using mechanochromic molecules in a shape memory thermoplastic matrix. Exposure to an alternating magnetic field (AMF) triggers shape recovery and facilitates damage repair. Magpol exhibited a linear strain response upto 150% strain and complete recovery after healing. We have demonstrated the use of this concept in a reusable biomedical device i.e., coated guidewires. Our findings offer a new synergistic method to bestow multifunctionality for applications ranging from medical device coatings to adaptive wing structures.

New structure of diamine curing agent for epoxy resins with self-restoration ability: Synthesis and spectroscopy characterization

NASA Astrophysics Data System (ADS)

Raimondo, Marialuigia; Guadagno, Liberata; Naddeo, Carlo; Longo, Pasquale; Mariconda, Annaluisa; Agovino, Anna

2017-02-01

The development of smart materials in aeronautical structures consisting of compounds based on epoxy resins having self-repair capability has been hampered by some criticalities. One of the main critical points is related to the impossibility to use primary amines (e.g.: 4,4‧-diaminodiphenyl sulfone, DDS) as hardeners, because they can poison the catalyst responsible for the healing mechanisms. In this paper, the synthesis, characterization and some tests of applicability of a new hardener, the tetramethylated diaminodiphenyl sulfone (tm-DDS), are shown. The tm-DDS is able to rapidly react with epoxy resin, giving a composite material having some characteristics significantly better than composites hardened with different tertiary amines. The new hardener is able to increase the glass transition temperature (Tg) of about 90 °C with respect to the more common hardener, ancamine K54, already used in self-healing epoxy formulations.

Synthesis of science and art: creating a new domestic world of sensual products

NASA Astrophysics Data System (ADS)

Thorpe, Chris; Friend, Clifford M.

1996-04-01

The creation of intelligent objects with sensual capabilities and caring personalities; objects which will share our domestic environments and our public spaces, is a vision at once both unnerving and inviting. As research into smart materials, intelligent material systems and the whole spectrum of related areas such as biomimetics, nano-technology and neural systems converge, we are now in a situation where in ten years intelligent objects could realize this lucid projection. The problem comes when we begin to look at the implications of such future object-environments. Our eagerness to solve the complex technical problems associated with the processing and manufacture of smart materials must be placed in the broader context of human considerations. If we are to realize their potential, and optimize the benefits which smart materials and intelligent material systems could bring to our quality of life, we must develop a new approach that is both technologically advanced and sympathetic towards human needs. An approach that is a synthesis of the objective reality sought through science and the irrational, emotional subjectivity embraced in the arts. This paper looks at the design of intelligent objects for the home, examining the role of design, the product interface and the relationship between objects and ourselves within the home environment.

Complex IoT Systems as Enablers for Smart Homes in a Smart City Vision.

PubMed

Lynggaard, Per; Skouby, Knud Erik

2016-11-02

The world is entering a new era, where Internet-of-Things (IoT), smart homes, and smart cities will play an important role in meeting the so-called big challenges. In the near future, it is foreseen that the majority of the world's population will live their lives in smart homes and in smart cities. To deal with these challenges, to support a sustainable urban development, and to improve the quality of life for citizens, a multi-disciplinary approach is needed. It seems evident, however, that a new, advanced Information and Communications Technology ICT infrastructure is a key feature to realize the "smart" vision. This paper proposes a specific solution in the form of a hierarchical layered ICT based infrastructure that handles ICT issues related to the "big challenges" and seamlessly integrates IoT, smart homes, and smart city structures into one coherent unit. To exemplify benefits of this infrastructure, a complex IoT system has been deployed, simulated and elaborated. This simulation deals with wastewater energy harvesting from smart buildings located in a smart city context. From the simulations, it has been found that the proposed infrastructure is able to harvest between 50% and 75% of the wastewater energy in a smart residential building. By letting the smart city infrastructure coordinate and control the harvest time and duration, it is possible to achieve considerable energy savings in the smart homes, and it is possible to reduce the peak-load for district heating plants.

Analysis of Distance Learning in Smart Schools in Iran: A Case Study of Tehran's Smart Schools

ERIC Educational Resources Information Center

Motamedi, Vahid; Piri, Roghayeh

2014-01-01

In the paradigm of information society the structure and facts have become flexible and subjective. In the recent social-economic order, IT and communication have taken over the leading role. Distance learning in smart schools is one of the flexible realities in the education field that has crossed the format of the hard and inflexible traditional…

A new type of magnetism-controllable Mn-based single-molecule magnet

NASA Astrophysics Data System (ADS)

Cui, Yan; Zhu, Huiping; Wang, Lei; Li, Bo; Han, Zhengsheng; Luo, Jiajun

2018-07-01

The flexibility and diversity of organic chemistry have yielded many materials in which magnetism can be varied. However, most methods used for changing magnetism are inefficient or destructive to the magnetic material. Here we report high-performance magnetic control of a gas-responsive single-molecule magnet (SMM). The results exhibit that the magnetic properties of the SMM can be significantly changed according to the gas environment it is in and some of the magnetic states can be reversibly transformed or coexistent in the SMM through artificial control. More importantly, the single crystalline structure of the SMM is almost the same during the transformation process except for slight change of the lattice constant. Thus, this work opens up new insights into the stimuli-responsive magnetic materials which have great prospects for application in artificial design magnetic network and also highlight their potential as smart materials.

Teaching Beer's Law and Absorption Spectrophotometry with a Smart Phone: A Substantially Simplified Protocol

ERIC Educational Resources Information Center

Kuntzleman, Thomas S.; Jacobson, Erik C.

2016-01-01

A very simple protocol for teaching Beer's Law and absorption spectrophotometry using a smart phone is described. Materials commonly found in high school chemistry laboratories or even around the house may be used. Data collection and analysis is quick and easy. Despite the simple nature of the experiment, excellent results can be achieved.

Smart Growth for a Sustainable Urban Environment - Concepts and Practice in US and China (CLASS PRESENTATION)

EPA Science Inventory

This is an invited seminar to a class of undergraduate and graduate students at DAAP of the University of Cincinnati. It provides students the concepts and trends in smart growth and sustainable urban development in U.S. and China. The materials are drawn from my research and m...

Data-driven Techniques to Estimate Parameters in the Homogenized Energy Model for Shape Memory Alloys

DTIC Science & Technology

2011-11-01

sensor. volume 79781K. Proceedings of the SPIE 7978, 2011. [9] D.J. Hartl , D.C. Lagoudas, F.T. Calkins, and J.H. Mabe . Use of a ni60ti shape memory...alloy for active jet engine chevron application: I. thermomechanical characterization. Smart Materials and Structures, 19:1–14, 2010. [10] D.J. Hartl ...D.C. Lagoudas, F.T. Calkins, and J.H. Mabe . Use of a ni60ti shape memory alloy for active jet engine chevron application: II. experimentally validated

Effect of Heat-Treatment on the Phases of Ni-Mn-Ga Magnetic Shape Memory Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huq, Ashfia; Ari-Gur, Pnina; Kimmel, Giora

2009-01-01

The Heusler alloys Ni50Mn25+xGa25-x display magnetic shape memory effect (MSM) with very fast and large reversible strain under magnetic fields. This large strain and the speed of reaction make MSM alloys attractive as smart materials. Our crystallographic investigation of these alloys, focused on non-stoichiometric composition with excess of manganese. Using neutron diffraction, we revealed the necessary processing parameters to achieve and preserve the homogeneous metastable one-phase martensitic structure that is needed for an MSM effect at room temperature.

Smart Materials for Army Structures

DTIC Science & Technology

1992-04-01

86. . 3 0.0 IMIA8 0 --’O IM S. B .88 . -I 30.0- 10.0 0 .0XI Fig. X4 Electrico o flte i ( eatv 2. andth It 0 / (A) 0-0 [90/0/90] 30.0 u...accomplished computationally, 137 i : D L (B) (C) --- Fig. X~III A demonstration of auto -rotation on a D-shaped blade of a Lancliester propellecr. 138 I...Conductive Polymers and Plastics, Chapman and Hall, 1989. Margolis, J.M., "Composites Challenge Metals for Aircraft/ Auto Panel Applications,’ Machine and

Optimization of Smart Structure for Improving Servo Performance of Hard Disk Drive

NASA Astrophysics Data System (ADS)

Kajiwara, Itsuro; Takahashi, Masafumi; Arisaka, Toshihiro

Head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, smart structure technology is introduced into the hard disk drive to suppress the vibration of the head actuator. It has been expected that the smart structure technology will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm. Vibration control effect with the proposed vibration control mechanisms has been evaluated by some simulations.

Future automotive materials: Evolution or revolution

NASA Technical Reports Server (NTRS)

Beardmore, P.

1990-01-01

An exciting era is evolving in the application of new materials technologies to automotive applications. The desire on the part of the automobile industry to completely satisfy the customers while concurrently meeting increasing demands and regulations for stringent emission control and fuel efficiency is opening a plethora of opportunities for new materials. In many cases, materials solutions are the only mechanisms for resolving some of the upcoming issues. The materials scientist and engineer will therefore have a primary role to play and will assume a position of significance hithertofore unseen in the automobile industry. The nature of the industry dictates that changes are primarily evolutionary with respect to chronology but nevertheless some of the future material changes will be revolutionary in nature. This presentation will treat three primary systems of the vehicle separately, based on the different materials approaches which will be adopted. These areas are: (1) skin panels, (2) structures, and (3) powertrains. The competition between a variety of new materials in these 3 systems will be discussed in detail with the various tradeoffs being outlined. Amongst the more prominent of the new breed of materials will be new steel technologies, structural plastics (FRP), aluminum alloys (conventional and rapidly solidified), titanium alloys, metal matrix composites and smart materials (electrorheological fluids, etc.). The pace of development and application is accelerating rapidly and the impetus is likely to increase.

Towards sensor array materials: can failure be delayed?

PubMed Central

Mekid, Samir; Saheb, Nouari; Khan, Shafique M A; Qureshi, Khurram K

2015-01-01

Further to prior development in enhancing structural health using smart materials, an innovative class of materials characterized by the ability to feel senses like humans, i.e. ‘nervous materials’, is discussed. Designed at all scales, these materials will enhance personnel and public safety, and secure greater reliability of products. Materials may fail suddenly, but any system wishes that failure is known in good time and delayed until safe conditions are reached. Nervous materials are expected to be the solution to this statement. This new class of materials is based on the novel concept of materials capable of feeling multiple structural and external stimuli, e.g. stress, force, pressure and temperature, while feeding information back to a controller for appropriate real-time action. The strain–stress state is developed in real time with the identified and characterized source of stimulus, with optimized time response to retrieve initial specified conditions, e.g. shape and strength. Sensors are volumetrically embedded and distributed, emulating the human nervous system. Immediate applications are in aircraft, cars, nuclear energy and robotics. Such materials will reduce maintenance costs, detect initial failures and delay them with self-healing. This article reviews the common aspects and challenges surrounding this new class of materials with types of sensors to be embedded seamlessly or inherently, including appropriate embedding manufacturing techniques with modeling and simulation methods. PMID:27877794

Towards sensor array materials: can failure be delayed?

NASA Astrophysics Data System (ADS)

Mekid, Samir; Saheb, Nouari; Khan, Shafique M. A.; Qureshi, Khurram K.

2015-06-01

Further to prior development in enhancing structural health using smart materials, an innovative class of materials characterized by the ability to feel senses like humans, i.e. ‘nervous materials’, is discussed. Designed at all scales, these materials will enhance personnel and public safety, and secure greater reliability of products. Materials may fail suddenly, but any system wishes that failure is known in good time and delayed until safe conditions are reached. Nervous materials are expected to be the solution to this statement. This new class of materials is based on the novel concept of materials capable of feeling multiple structural and external stimuli, e.g. stress, force, pressure and temperature, while feeding information back to a controller for appropriate real-time action. The strain-stress state is developed in real time with the identified and characterized source of stimulus, with optimized time response to retrieve initial specified conditions, e.g. shape and strength. Sensors are volumetrically embedded and distributed, emulating the human nervous system. Immediate applications are in aircraft, cars, nuclear energy and robotics. Such materials will reduce maintenance costs, detect initial failures and delay them with self-healing. This article reviews the common aspects and challenges surrounding this new class of materials with types of sensors to be embedded seamlessly or inherently, including appropriate embedding manufacturing techniques with modeling and simulation methods.

SMART GROUND Project: SMART data collection and inteGRation platform to enhance availability and accessibility of data and infOrmation in the EU territory on SecoNDary Raw Materials

NASA Astrophysics Data System (ADS)

Rossetti, Piergiorgio; Antonella Dino, Giovanna; de la Feld, Marco; Pizza, Antonietta; Coulon, Frederic; Wagland, Stuart; Gomes, Diogo

2016-04-01

The issue of resource security has come to the forefront of the debate over recent years, partly due to considerable concern over the security of supply of the so called 'critical' materials, with rare earths attracting the greatest attention in the press. Their supply is fundamental to maintain and develop EU economy and its industries relied on a steady supply of Raw Materials. Thus considering the increasing scarcity and raising prices of both, energy raw materials and other raw materials, such as metals and minerals, the recycling and recovery of these materials from anthropogenic deposits such as landfills is of increasing relevance. Europe has somewhere between 150,000 and 500,000 landfill sites, with an estimated 90% of them being "non-sanitary" pre-dating the EU Landfill Directive of 1999. Thus historical background makes the numerous old waste dumps as possible sources of critical and secondary raw materials (SRM and CRM). However, to date there is no inventory available of SRM and CRM present in EU landfills, and best management practices to recover SRM from landfill activities are inefficient. In this context, the EU SMART GROUND (SG) project (Grant Agreement No 641988) intends to foster resource recovery in landfills by improving both the availability and the accessibility of data and information on SRM in the EU and creating synergies among the different stakeholders involved in the SRM value chain. To do so, the project aims to collect and integrate in a single EU databank (SMART GROUND Data Bank) all the data from existing databases and new information retrieved during project activities. Such data will be collected from the different waste streams including municipal, industrial and mining wastes across EU landfills. It will improve data gathering on SRM from different types of waste, by defining new and integrated data acquisition methods and standards. At last, but not least, the project will also improve the SRM economic and employment potential, by i) providing training on the assessment of landfill sites material recovery to targeting end-users, ii) establishing a dedicated network of academic, industrial, regulators and other stakeholders committed to cost-effective research, technology transfer and training. The present contribution will provide an overview of the SMART GROUND project and highlights the results obtained during the first six months of project activity.

Active control of transmission loss with smart foams.

PubMed

Kundu, Abhishek; Berry, Alain

2011-02-01

Smart foams combine the complimentary advantages of passive foam material and spatially distributed piezoelectric actuator embedded in it for active noise control applications. In this paper, the problem of improving the transmission loss of smart foams using active control strategies has been investigated both numerically and experimentally inside a waveguide under the condition of plane wave propagation. The finite element simulation of a coupled noise control system has been undertaken with three different smart foam designs and their effectiveness in cancelling the transmitted wave downstream of the smart foam have been studied. The simulation results provide insight into the physical phenomenon of active noise cancellation and explain the impact of the smart foam designs on the optimal active control results. Experimental studies aimed at implementing the real-time control for transmission loss optimization have been performed using the classical single input/single output filtered-reference least mean squares algorithm. The active control results with broadband and single frequency primary source inputs demonstrate a good improvement in the transmission loss of the smart foams. The study gives a comparative description of the transmission and absorption control problems in light of the modification of the vibration response of the piezoelectric actuator under active control.

The role of advanced sensing in smart cities.

PubMed

Hancke, Gerhard P; Silva, Bruno de Carvalho E; Hancke, Gerhard P

2012-12-27

In a world where resources are scarce and urban areas consume the vast majority of these resources, it is vital to make cities greener and more sustainable. Advanced systems to improve and automate processes within a city will play a leading role in smart cities. From smart design of buildings, which capture rain water for later use, to intelligent control systems, which can monitor infrastructures autonomously, the possible improvements enabled by sensing technologies are immense. Ubiquitous sensing poses numerous challenges, which are of a technological or social nature. This paper presents an overview of the state of the art with regards to sensing in smart cities. Topics include sensing applications in smart cities, sensing platforms and technical challenges associated with these technologies. In an effort to provide a holistic view of how sensing technologies play a role in smart cities, a range of applications and technical challenges associated with these applications are discussed. As some of these applications and technologies belong to different disciplines, the material presented in this paper attempts to bridge these to provide a broad overview, which can be of help to researchers and developers in understanding how advanced sensing can play a role in smart cities.

The Role of Advanced Sensing in Smart Cities

PubMed Central

Hancke, Gerhard P.; de Carvalho e Silva, Bruno; Hancke, Gerhard P.

2013-01-01

In a world where resources are scarce and urban areas consume the vast majority of these resources, it is vital to make cities greener and more sustainable. Advanced systems to improve and automate processes within a city will play a leading role in smart cities. From smart design of buildings, which capture rain water for later use, to intelligent control systems, which can monitor infrastructures autonomously, the possible improvements enabled by sensing technologies are immense. Ubiquitous sensing poses numerous challenges, which are of a technological or social nature. This paper presents an overview of the state of the art with regards to sensing in smart cities. Topics include sensing applications in smart cities, sensing platforms and technical challenges associated with these technologies. In an effort to provide a holistic view of how sensing technologies play a role in smart cities, a range of applications and technical challenges associated with these applications are discussed. As some of these applications and technologies belong to different disciplines, the material presented in this paper attempts to bridge these to provide a broad overview, which can be of help to researchers and developers in understanding how advanced sensing can play a role in smart cities. PMID:23271603

Research of a smart cutting tool based on MEMS strain gauge

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zhao, Y. L.; Shao, YW; Hu, T. J.; Zhang, Q.; Ge, X. H.

2018-03-01

Cutting force is an important factor that affects machining accuracy, cutting vibration and tool wear. Machining condition monitoring by cutting force measurement is a key technology for intelligent manufacture. Current cutting force sensors exist problems of large volume, complex structure and poor compatibility in practical application, for these problems, a smart cutting tool is proposed in this paper for cutting force measurement. Commercial MEMS (Micro-Electro-Mechanical System) strain gauges with high sensitivity and small size are adopted as transducing element of the smart tool, and a structure optimized cutting tool is fabricated for MEMS strain gauge bonding. Static calibration results show that the developed smart cutting tool is able to measure cutting forces in both X and Y directions, and the cross-interference error is within 3%. Its general accuracy is 3.35% and 3.27% in X and Y directions, and sensitivity is 0.1 mV/N, which is very suitable for measuring small cutting forces in high speed and precision machining. The smart cutting tool is portable and reliable for practical application in CNC machine tool.

Smart Floor with Integrated Triboelectric Nanogenerator As Energy Harvester and Motion Sensor.

PubMed

He, Chuan; Zhu, Weijun; Chen, Baodong; Xu, Liang; Jiang, Tao; Han, Chang Bao; Gu, Guang Qin; Li, Dichen; Wang, Zhong Lin

2017-08-09

A smart floor is demonstrated by integrating a square-frame triboelectric nanogenerator (SF-TENG) into a standard wood floor. The smart floor has two working modes based on two pairs of triboelectric materials: one is purposely chosen polytetrafluoroethylene films and aluminum (Al) balls, and the other is the floor itself and the objects that can be triboelectrically charged, such as basketball, shoe soles, and Scotch tape, etc. Utilizing the Al balls enclosed inside shallow boxes, the smart floor is capable of harvesting vibrational energy and, hence, provides a nonintrusive way to detect sudden falls in elderly people. In addition, when the basketball is bounced repeatedly on the floor, the average output voltage and current are 364 ± 43 V and 9 ± 1 μA, respectively, and 87 serially connected light-emitting diodes can be lit up simultaneously. Furthermore, the friction between the triboelectrically chargeable objects and the floor can also induce an alternating current output in the external circuit without the vibration of the Al balls. Normal human footsteps on the floor produce a voltage of 238 ± 17 V and a current of 2.4 ± 0.3 μA. Therefore, this work presents a smart floor with built-in SF-TENG without compromising the flexibility and stability of the standard wood floor and also demonstrates a way to harvest ambient energy solely by using conventional triboelectric materials in our daily life.

Bioinspired Fabrication of one dimensional graphene fiber with collection of droplets application.

PubMed

Song, Yun-Yun; Liu, Yan; Jiang, Hao-Bo; Li, Shu-Yi; Kaya, Cigdem; Stegmaier, Thomas; Han, Zhi-Wu; Ren, Lu-Quan

2017-09-21

We designed a kind of smart bioinspired fiber with multi-gradient and multi-scale spindle knots by combining polydimethylsiloxane (PDMS) and graphene oxide (GO). Multilayered graphene structures can produce obvious wettability change after laser etching due to increased roughness. We demonstrate that the cooperation between curvature and the controllable wettability play an important role in water gathering, which regulate effectively the motion of tiny water droplets. In addition, due to the effective cooperation of multi-gradient and multi-scale hydrophilic spindle knots, the length of the three-phase contact line (TCL) can be longer, which makes a great contribution to the improvement of collecting efficiency and water-hanging ability. This study offers a novel insight into the design of smart materials that may control the transport of tiny drops reversibly in directions, which could potentially be extended to the realms of in microfluidics, fog harvesting filtration and condensers designs, and further increase water collection efficiency and hanging ability.

Pilot symbol-assisted beamforming algorithms in the WCDMA reverse link

NASA Astrophysics Data System (ADS)

Kong, Dongkeon; Lee, Jong H.; Chun, Joohwan; Woo, Yeon Sik; Soh, Ju Won

2001-08-01

We present a pilot symbol-assisted beamforming algorithm and a simulation tool of smart antennas for Wideband Code Division Multiple Access (WCDMA) in reverse link. In the 3GPP WCDMA system smart antenna technology has more room to play with than in the second generation wireless mobile systems such as IS-95 because the pilot symbol in Dedicated Physical Control Channel (DPCCH) can be utilized. First we show a smart antenna structure and adaptation algorithms, and then we explain a low-level smart antenna implementation using Simulink and MATLAB. In the design of our smart antenna system we pay special attention for the easiness of the interface to the baseband modem; Our ultimate goal is to implement a baseband smart antenna chip sets that can easily be added to to-be-existed baseband WCDMA modem units.

Complex IoT Systems as Enablers for Smart Homes in a Smart City Vision

PubMed Central

Lynggaard, Per; Skouby, Knud Erik

2016-01-01

The world is entering a new era, where Internet-of-Things (IoT), smart homes, and smart cities will play an important role in meeting the so-called big challenges. In the near future, it is foreseen that the majority of the world’s population will live their lives in smart homes and in smart cities. To deal with these challenges, to support a sustainable urban development, and to improve the quality of life for citizens, a multi-disciplinary approach is needed. It seems evident, however, that a new, advanced Information and Communications Technology ICT infrastructure is a key feature to realize the “smart” vision. This paper proposes a specific solution in the form of a hierarchical layered ICT based infrastructure that handles ICT issues related to the “big challenges” and seamlessly integrates IoT, smart homes, and smart city structures into one coherent unit. To exemplify benefits of this infrastructure, a complex IoT system has been deployed, simulated and elaborated. This simulation deals with wastewater energy harvesting from smart buildings located in a smart city context. From the simulations, it has been found that the proposed infrastructure is able to harvest between 50% and 75% of the wastewater energy in a smart residential building. By letting the smart city infrastructure coordinate and control the harvest time and duration, it is possible to achieve considerable energy savings in the smart homes, and it is possible to reduce the peak-load for district heating plants. PMID:27827851

Transformation of food packaging from passive to innovative via nanotechnology: concepts and critiques.

PubMed

Mlalila, Nichrous; Kadam, Dattatreya M; Swai, Hulda; Hilonga, Askwar

2016-09-01

In recent decades, there is a global advancement in manufacturing industry due to increased applications of nanotechnology. Food industry also has been tremendously changing from passive packaging to innovative packaging, to cope with global trends, technological advancements, and consumer preferences. Active research is taking place in food industry and other scientific fields to develop innovative packages including smart, intelligent and active food packaging for more effective and efficient packaging materials with balanced environmental issues. However, in food industry the features behind smart packaging are narrowly defined to be distinguished from intelligent packaging as in other scientific fields, where smart materials are under critical investigations. This review presents some scientific concepts and features pertaining innovative food packaging. The review opens new research window in innovative food packaging to cover the existing disparities for further precise research and development of food packaging industry.

A new type of smart basalt fiber-reinforced polymer bars as both reinforcements and sensors for civil engineering application

NASA Astrophysics Data System (ADS)

Tang, Yongsheng; Wu, Zhishen; Yang, Caiqian; Wu, Gang; Shen, Sheng

2010-11-01

In this paper, a new type of smart basalt fiber-reinforced polymer (BFRP) bar is developed and their sensing performance is investigated by using the Brillouin scattering-based distributed fiber optic sensing technique. The industrial manufacturing process is first addressed, followed by an experimental study on the strain, temperature and fundamental mechanical properties of the BFRP bars. The results confirm the superior sensing properties, in particular the measuring accuracy, repeatability and linearity through comparing with bare optical fibers. Results on the mechanical properties show stable elastic modulus and high ultimate strength. Therefore, the smart BFRP bar has potential applications for long-term structural health monitoring (SHM) as embedded sensors as well as strengthening and upgrading structures. Moreover the coefficient of thermal expansion for smart BFRP bars is similar to the value for concrete.

An Exploratory Study to Measure Excessive Involvement in Multitasking Interaction with Smart Devices.

PubMed

Zhang, Yubo; Rau, Pei-Luen Patrick

2016-06-01

This study developed a scale measuring excessive involvement in multitasking interaction with smart devices. An online questionnaire was designed and surveyed in a sample of 380 respondents. The sample was split into two groups for exploratory and confirmatory factor analysis, respectively. A four-factor structure was identified with an acceptable goodness of fit. The first two factors, "Obsession and neglect" and "Problematic control," described the obsessive feelings, neglect behaviors, and behavior control problems accompanied by excessive multitasking interaction with smart devices. The latter two factors, "Multitasking preference" and "Polychronic orientation," referred to multitaskers' preference of engaging in multiple media use or interaction tasks rather than a single task from the time orientation perspective. The four-factor structure indicates that excessive involvement in multitasking interaction with smart devices shares some similarities with other behavioral addiction types, but demonstrates uniqueness compared with excessive engagement in single media use.

Smart release of doxorubicin loaded on polyetheretherketone (PEEK) surface with 3D porous structure.

PubMed

Ouyang, Liping; Sun, Zhenjie; Wang, Donghui; Qiao, Yuqin; Zhu, Hongqin; Ma, Xiaohan; Liu, Xuanyong

2018-03-01

It is important to fabricate an implant possessing environment sensitive drug delivery. In this work, the construction of 3D porous structure on polyetheretherketone (PEEK) surface and pH sensitive polymer, chitosan, was introduced. The smart release of doxorubicin can be realized on the 3D porous surface of PEEK loading chitosan. We give a feasible explanation for the effect of chitosan on smart drug release according to Henderson-Hasselbalch equation. Furthermore, the intracellular drug content of the cell cultured on the samples with highest chitosan is significantly higher at pH 4.0, whereas lower at pH 7.4 than other samples. The smart release of doxorubicin via modification with chitosan onto 3D porous PEEK surface paves the way for the application of PEEK in drug loading platform for recovering bone defect caused by malignant bone tumor. Copyright © 2017 Elsevier B.V. All rights reserved.

Light-responsive expansion-contraction of spherical nanoparticle grafted with azopolymers

NASA Astrophysics Data System (ADS)

Fu, Jie; Zhang, Xinghua; Miao, Bing; Yan, Dadong

2017-04-01

Due to the very importance for both fundamental research and technological applications, smart materials with stimuli-responsive properties have been studied intensively. Theoretical investigation contributes to this endeavor through constructing and analyzing a model system which captures main features of the corresponding complex material, wherefrom useful insight can be provided to the trial-and-error experiments. We here report a theoretical study on the smart spherical nanoparticle grafted with light-responsive azobenzene-containing polymers. Utilizing the photoisomerization ability of the azobenzene group, nanoparticles can undergo a light-induced expansion-contraction transition. The wormlike chain based single chain in mean field theory, which has been developed by us recently, is used to investigate this transition in detail. Exploring a large parameter space, our results definitely determine the parameters, including the chain length and effective Kuhn length of grafted chain, nanoparticle radius, grafting density, and position of the azobenzene group along the chain contour, to admit optimum light-responsive behavior of the smart nanoparticle, which provides a guide for experimentalists to design this type of material in a rational manner.

Smooth adaptive sliding mode vibration control of a flexible parallel manipulator with multiple smart linkages in modal space

NASA Astrophysics Data System (ADS)

Zhang, Quan; Li, Chaodong; Zhang, Jiantao; Zhang, Jianhui

2017-12-01

This paper addresses the dynamic model and active vibration control of a rigid-flexible parallel manipulator with three smart links actuated by three linear ultrasonic motors. To suppress the vibration of three flexible intermediate links under high speed and acceleration, multiple Lead Zirconium Titanate (PZT) sensors and actuators are collocated mounted on each link, forming a smart structure which can achieve self-sensing and self-actuating. The dynamic characteristics and equations of the flexible link incorporated with the PZT sensors and actuator are analyzed and formulated. The smooth adaptive sliding mode based active vibration control is proposed to suppress the vibration of the smart links, and the first and second modes of the three links are targeted to be suppressed in modal space to avoid the spillover phenomenon. Simulations and experiments are implemented to validate the effectiveness of the smart structures and the proposed control laws. Experimental results show that the vibration of the first mode around 92 Hz and the second mode around 240 Hz of the three smart links are reduced respectively by 64.98%, 59.47%, 62.28%, and 45.80%, 36.79%, 33.33%, which further verify the multi-mode vibration control ability of the smooth adaptive sliding mode control law.

Electronics for Piezoelectric Smart Structures

NASA Technical Reports Server (NTRS)

Warkentin, D. J.; Tani, J.

1997-01-01

This paper briefly presents work addressing some of the basic considerations for the electronic components used in smart structures incorporating piezoelectric elements. After general remarks on the application of piezoelectric elements to the problem of structural vibration control, three main topics are described. Work to date on the development of techniques for embedding electronic components within structural parts is presented, followed by a description of the power flow and dissipation requirements of those components. Finally current work on the development of electronic circuits for use in an 'active wall' for acoustic noise is introduced.

Ab initio structure determination and quantitative disorder analysis on nanoparticles by electron diffraction tomography.

PubMed

Krysiak, Yaşar; Barton, Bastian; Marler, Bernd; Neder, Reinhard B; Kolb, Ute

2018-03-01

Nanoscaled porous materials such as zeolites have attracted substantial attention in industry due to their catalytic activity, and their performance in sorption and separation processes. In order to understand the properties of such materials, current research focuses increasingly on the determination of structural features beyond the averaged crystal structure. Small particle sizes, various types of disorder and intergrown structures render the description of structures at atomic level by standard crystallographic methods difficult. This paper reports the characterization of a strongly disordered zeolite structure, using a combination of electron exit-wave reconstruction, automated diffraction tomography (ADT), crystal disorder modelling and electron diffraction simulations. Zeolite beta was chosen for a proof-of-principle study of the techniques, because it consists of two different intergrown polymorphs that are built from identical layer types but with different stacking sequences. Imaging of the projected inner Coulomb potential of zeolite beta crystals shows the intergrowth of the polymorphs BEA and BEB. The structures of BEA as well as BEB could be extracted from one single ADT data set using direct methods. A ratio for BEA/BEB = 48:52 was determined by comparison of the reconstructed reciprocal space based on ADT data with simulated electron diffraction data for virtual nanocrystals, built with different ratios of BEA/BEB. In this way, it is demonstrated that this smart interplay of the above-mentioned techniques allows the elaboration of the real structures of functional materials in detail - even if they possess a severely disordered structure.

On the Use of Piezoelectric Sensors in Structural Mechanics: Some Novel Strategies

PubMed Central

Irschik, Hans; Krommer, Michael; Vetyukov, Yury

2010-01-01

In the present paper, a review on piezoelectric sensing of mechanical deformations and vibrations of so-called smart or intelligent structures is given. After a short introduction into piezoelectric sensing and actuation of such controlled structures, we pay special emphasis on the description of some own work, which has been performed at the Institute of Technical Mechanics of the Johannes Kepler University of Linz (JKU) in the last years. Among other aspects, this work has been motivated by the fact that collocated control of smart structures requires a sensor output that is work-conjugated to the input by the actuator. This fact in turn brings into the play the more general question of how to measure mechanically meaningful structural quantities, such as displacements, slopes, or other quantities, which form the work-conjugated quantities of the actuation, by means piezoelectric sensors. At least in the range of small strains, there is confidence that distributed piezoelectric sensors or sensor patches in smart structures do measure weighted integrals over their domain. Therefore, there is a need of distributing or shaping the sensor activity in order to be able to re-interpret the sensor signals in the desired mechanical sense. We sketch a general strategy that is based on a special application of work principles, more generally on displacement virials. We also review our work in the past on bringing this concept to application in smart structures, such as beams, rods and plates. PMID:22219679

On the use of piezoelectric sensors in structural mechanics: some novel strategies.

PubMed

Irschik, Hans; Krommer, Michael; Vetyukov, Yury

2010-01-01

In the present paper, a review on piezoelectric sensing of mechanical deformations and vibrations of so-called smart or intelligent structures is given. After a short introduction into piezoelectric sensing and actuation of such controlled structures, we pay special emphasis on the description of some own work, which has been performed at the Institute of Technical Mechanics of the Johannes Kepler University of Linz (JKU) in the last years. Among other aspects, this work has been motivated by the fact that collocated control of smart structures requires a sensor output that is work-conjugated to the input by the actuator. This fact in turn brings into the play the more general question of how to measure mechanically meaningful structural quantities, such as displacements, slopes, or other quantities, which form the work-conjugated quantities of the actuation, by means piezoelectric sensors. At least in the range of small strains, there is confidence that distributed piezoelectric sensors or sensor patches in smart structures do measure weighted integrals over their domain. Therefore, there is a need of distributing or shaping the sensor activity in order to be able to re-interpret the sensor signals in the desired mechanical sense. We sketch a general strategy that is based on a special application of work principles, more generally on displacement virials. We also review our work in the past on bringing this concept to application in smart structures, such as beams, rods and plates.

Tuning acoustic and mechanical properties of materials for ultrasound phantoms and smart substrates for cell cultures.

PubMed

Cafarelli, A; Verbeni, A; Poliziani, A; Dario, P; Menciassi, A; Ricotti, L

2017-02-01

Materials with tailored acoustic properties are of great interest for both the development of tissue-mimicking phantoms for ultrasound tests and smart scaffolds for ultrasound mediated tissue engineering and regenerative medicine. In this study, we assessed the acoustic properties (speed of sound, acoustic impedance and attenuation coefficient) of three different materials (agarose, polyacrylamide and polydimethylsiloxane) at different concentrations or cross-linking levels and doped with different concentrations of barium titanate ceramic nanoparticles. The selected materials, besides different mechanical features (stiffness from few kPa to 1.6MPa), showed a wide range of acoustic properties (speed of sound from 1022 to 1555m/s, acoustic impedance from 1.02 to 1.67MRayl and attenuation coefficient from 0.2 to 36.5dB/cm), corresponding to ranges in which natural soft tissues can fall. We demonstrated that this knowledge can be used to build tissue-mimicking phantoms for ultrasound-based medical procedures and that the mentioned measurements enable to stimulate cells with a highly controlled ultrasound dose, taking into account the attenuation due to the cell-supporting scaffold. Finally, we were able to correlate for the first time the bioeffect on human fibroblasts, triggered by piezoelectric barium titanate nanoparticles activated by low-intensity pulsed ultrasound, with a precise ultrasound dose delivered. These results may open new avenues for the development of both tissue-mimicking materials for ultrasound phantoms and smart triggerable scaffolds for tissue engineering and regenerative medicine. This study reports for the first time the results of a systematic acoustic characterization of agarose, polyacrylamide and polydimethylsiloxane at different concentrations and cross-linking extents and doped with different concentrations of barium titanate nanoparticles. These results can be used to build tissue-mimicking phantoms, useful for many ultrasound-based medical procedures, and to fabricate smart materials for stimulating cells with a highly controlled ultrasound dose. Thanks to this knowledge, we correlated for the first time a bioeffect (the proliferation increase) on human fibroblasts, triggered by piezoelectric nanoparticles, with a precise US dose delivered. These results may open new avenues for the development of both tissue-mimicking phantoms and smart triggerable scaffolds for tissue engineering and regenerative medicine. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.