Science.gov

Sample records for aerospace structural components

  1. Optimum Design of Aerospace Structural Components Using Neural Networks

    NASA Technical Reports Server (NTRS)

    Berke, L.; Patnaik, S. N.; Murthy, P. L. N.

    1993-01-01

    The application of artificial neural networks to capture structural design expertise is demonstrated. The principal advantage of a trained neural network is that it requires a trivial computational effort to produce an acceptable new design. For the class of problems addressed, the development of a conventional expert system would be extremely difficult. In the present effort, a structural optimization code with multiple nonlinear programming algorithms and an artificial neural network code NETS were used. A set of optimum designs for a ring and two aircraft wings for static and dynamic constraints were generated using the optimization codes. The optimum design data were processed to obtain input and output pairs, which were used to develop a trained artificial neural network using the code NETS. Optimum designs for new design conditions were predicted using the trained network. Neural net prediction of optimum designs was found to be satisfactory for the majority of the output design parameters. However, results from the present study indicate that caution must be exercised to ensure that all design variables are within selected error bounds.

  2. Analysis of fatigue, fatique-crack propagation, and fracture data. [design of metallic aerospace structural components

    NASA Technical Reports Server (NTRS)

    Jaske, C. E.; Feddersen, C. E.; Davies, K. B.; Rice, R. C.

    1973-01-01

    Analytical methods have been developed for consolidation of fatigue, fatigue-crack propagation, and fracture data for use in design of metallic aerospace structural components. To evaluate these methods, a comprehensive file of data on 2024 and 7075 aluminums, Ti-6A1-4V, and 300M and D6Ac steels was established. Data were obtained from both published literature and unpublished reports furnished by aerospace companies. Fatigue and fatigue-crack-propagation analyses were restricted to information obtained from constant-amplitude load or strain cycling of specimens in air at room temperature. Fracture toughness data were from tests of center-cracked tension panels, part-through crack specimens, and compact-tension specimens.

  3. Practical theories for service life prediction of critical aerospace structural components

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Monaghan, Richard C.; Jackson, Raymond H.

    1992-01-01

    A new second-order theory was developed for predicting the service lives of aerospace structural components. The predictions based on this new theory were compared with those based on the Ko first-order theory and the classical theory of service life predictions. The new theory gives very accurate service life predictions. An equivalent constant-amplitude stress cycle method was proposed for representing the random load spectrum for crack growth calculations. This method predicts the most conservative service life. The proposed use of minimum detectable crack size, instead of proof load established crack size as an initial crack size for crack growth calculations, could give a more realistic service life.

  4. Reducing Undue Conservatism in "Higher Frequency" Structural Design Loads in Aerospace Components

    NASA Technical Reports Server (NTRS)

    Knight, J. Brent

    2012-01-01

    This study is intended to investigate the frequency dependency of significant strain due to vibratory loads in aerospace vehicle components. The notion that "higher frequency" dynamic loads applied as static loads is inherently conservative is perceived as widely accepted. This effort is focused on demonstrating that principle and attempting to evolve methods to capitalize on it to mitigate undue conservatism. It has been suggested that observations of higher frequency modes that resulted in very low corresponding strain did so due to those modes not being significant. Two avionics boxes, one with its first significant mode at 341 Hz and the other at 857 Hz, were attached to a flat panel installed on a curved orthogrid panel which was driven acoustically in tests performed at NASA/MSFC. Strain and acceleration were measured at select locations on each of the boxes. When possible, strain gage rosettes and accelerometers were installed on either side of a given structural member so that measured strain and acceleration data would directly correspond to one another. Ultimately, a frequency above which vibratory loads can be disregarded for purposes of static structural analyses and sizing of typical robust aerospace components is sought.

  5. Trends in aerospace structures

    NASA Technical Reports Server (NTRS)

    Card, M. F.

    1978-01-01

    Recent developments indicate that there may soon be a revolution in aerospace structures. Increases in allowable operational stress levels, utilization of high-strength, high-toughness materials, and new structural concepts will highlight this advancement. Improved titanium and aluminum alloys and high-modulus, high-strength advanced composites, with higher specific properties than aluminum and high-strength nickel alloys, are expected to be the principal materials. Significant advances in computer technology will cause major changes in the preliminary design cycle and permit solutions of otherwise too-complex interactive structural problems and thus the development of vehicles and components of higher performance. The energy crisis will have an impact on material costs and choices and will spur the development of more weight-efficient structures. There will also be significant spinoffs of aerospace structures technology, particularly in composites and design/analysis software.

  6. AI aerospace components

    SciTech Connect

    Heindel, T.A.; Murphy, T.B.; Rasmussen, A.N.; Mcfarland, R.Z.; Montgomery, R.E.; Pohle, G.E.; Heard, A.E.; Atkinson, D.J.; Wedlake, W.E.; Anderson, J.M. Mitre Corp., Houston, TX Unisys Corp., Houston, TX Rockwell International Corp., El Segundo, CA NASA, Kennedy Space Center, Cocoa Beach, FL JPL, Pasadena, CA Lockheed Missiles and Space Co., Inc., Austin, TX McDonnell Douglas Electronic Systems Co., McLean, VA )

    1991-10-01

    An evaluation is made of the application of novel, AI-capabilities-related technologies to aerospace systems. Attention is given to expert-system shells for Space Shuttle Orbiter mission control, manpower and processing cost reductions at the NASA Kennedy Space Center's 'firing rooms' for liftoff monitoring, the automation of planetary exploration systems such as semiautonomous mobile robots, and AI for battlefield staff-related functions.

  7. X-ray simulation for structural integrity for aerospace components - A case study

    NASA Astrophysics Data System (ADS)

    Singh, Surendra; Gray, Joseph

    2016-02-01

    The use of Integrated Computational Materials Engineering (ICME) has rapidly evolved from an emerging technology to the industry standards in Materials, Manufacturing, Chemical, Civil, and Aerospace engineering. Despite this the recognition of the ICME merits has been somewhat lacking within NDE community. This is due in part to the makeup of NDE practitioners. They are a very diverse but regimented group. More than 80% of NDE experts are trained and certified as NDT Level 3's and auditors in order to perform their daily inspection jobs. These jobs involve detection of attribute of interest, which may be a defect or condition or both, in a material. These jobs are performed in strict compliance with procedures that have been developed over many years by trial-and-error with minimal understanding of the underlying physics and interplay between the NDE methods setup parameters. It is not in the nature of these trained Level 3's experts to look for alternate or out-of-the box, solutions. Instead, they follow the procedures for compliance as required by regulatory agencies. This approach is time-consuming, subjective, and is treated as a bottleneck in today's manufacturing environments. As such, there is a need for new NDE tools that provide rapid, high quality solutions for studying structural and dimensional integrity in parts at a reduced cost. NDE simulations offer such options by a shortening NDE technique development-time, attaining a new level in the scientific understanding of physics of interactions between interrogating energy and materials, and reducing costs. In this paper, we apply NDE simulation (XRSIM as an example) for simulating X-Ray techniques for studying aerospace components. These results show that NDE simulations help: 1) significantly shorten NDE technique development-time, 2) assist in training NDE experts, by facilitating the understanding of the underlying physics, and 3) improve both capability and reliability of NDE methods in terms of

  8. Additive Manufacturing of Aerospace Propulsion Components

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.; Grady, Joseph E.; Carter, Robert

    2015-01-01

    The presentation will provide an overview of ongoing activities on additive manufacturing of aerospace propulsion components, which included rocket propulsion and gas turbine engines. Future opportunities on additive manufacturing of hybrid electric propulsion components will be discussed.

  9. Aerospace structures supportability

    NASA Astrophysics Data System (ADS)

    Smith, Howard Wesley

    1989-04-01

    This paper is about supportability in its general sense, with emphasis on aerospace structures. Reliability and maintainability (R&M) are described and defined from the standpoint of both structural analysis. Accessability, inspectability, and replaceability are described as design attributes. Reliability and probability of failure are shown to be in the domain of the analysis. Availability and replaceability are traditional logistic responsibilities which are influenced by supportability engineers. The USAF R&M 2000 process is described, and the R&M 1988 Workshop at Wright-Patterson Air Force Base is also included in the description.

  10. Damage Assessment of Aerospace Structural Components by Impedance Based Health Monitoring

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, Andrew L.; Martin, Richard E.; Sawicki, Jerzy T.; Baaklini, George Y.

    2005-01-01

    This paper addresses recent efforts at the NASA Glenn Research Center at Lewis Field relating to the set-up and assessment of electro-mechanical (E/M) impedance based structural health monitoring. The overall aim is the application of the impedance based technique to aeronautic and space based structural components. As initial steps, a laboratory was created, software written, and experiments conducted on aluminum plates in undamaged and damaged states. A simulated crack, in the form of a narrow notch at various locations, was analyzed using piezoelectric-ceramic (PZT: lead, zirconate, titarate) patches as impedance measuring transducers. Descriptions of the impedance quantifying hardware and software are provided as well as experimental results. In summary, an impedance based health monitoring system was assembled and tested. The preliminary data showed that the impedance based technique was successful in recognizing the damage state of notched aluminum plates.

  11. Application of artificial neural networks to the design optimization of aerospace structural components

    NASA Technical Reports Server (NTRS)

    Berke, Laszlo; Patnaik, Surya N.; Murthy, Pappu L. N.

    1993-01-01

    The application of artificial neural networks to capture structural design expertise is demonstrated. The principal advantage of a trained neural network is that it requires trivial computational effort to produce an acceptable new design. For the class of problems addressed, the development of a conventional expert system would be extremely difficult. In the present effort, a structural optimization code with multiple nonlinear programming algorithms and an artificial neural network code NETS were used. A set of optimum designs for a ring and two aircraft wings for static and dynamic constraints were generated by using the optimization codes. The optimum design data were processed to obtain input and output pairs, which were used to develop a trained artificial neural network with the code NETS. Optimum designs for new design conditions were predicted by using the trained network. Neural net prediction of optimum designs was found to be satisfactory for most of the output design parameters. However, results from the present study indicate that caution must be exercised to ensure that all design variables are within selected error bounds.

  12. Lattice Structures For Aerospace Applications

    NASA Astrophysics Data System (ADS)

    Del Olmo, E.; Grande, E.; Samartin, C. R.; Bezdenejnykh, M.; Torres, J.; Blanco, N.; Frovel, M.; Canas, J.

    2012-07-01

    The way of mass reduction improving performances in the aerospace structures is a constant and relevant challenge in the space business. The designs, materials and manufacturing processes are permanently in evolution to explore and get mass optimization solutions at low cost. In the framework of ICARO project, EADS CASA ESPACIO (ECE) has designed, manufactured and tested a technology demonstrator which shows that lattice type of grid structures is a promising weight saving solution for replacing some traditional metallic and composite structures for space applications. A virtual testing methodology was used in order to support the design of a high modulus CFRP cylindrical lattice technology demonstrator. The manufacturing process, based on composite Automatic Fiber Placement (AFP) technology developed by ECE, allows obtaining high quality low weight lattice structures potentially applicable to a wide range of aerospace structures. Launcher payload adaptors, satellite platforms, antenna towers or instrument supports are some promising candidates.

  13. Optimization of aerospace structures

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Patnaik, Surya N.

    1994-01-01

    Research carried out is grouped under two topics: (1) Design Optimization, and (2) Integrated Force Method of Analysis. Design Optimization Research Topics are singularity alleviation enhances structural optimization methods, computer based design capability extended through substructure synthesis, and optimality criteria provides optimum design for a select class of structural problems. Integrated Force Method of Analysis Research Topics are boundary compatibility formulation improves stress analysis of shell structures. Brief descriptions of the four topics are appended.

  14. Computational composite mechanics for aerospace propulsion structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1986-01-01

    Specialty methods are presented for the computational simulation of specific composite behavior. These methods encompass all aspects of composite mechanics, impact, progressive fracture and component specific simulation. Some of these methods are structured to computationally simulate, in parallel, the composite behavior and history from the initial fabrication through several missions and even to fracture. Select methods and typical results obtained from such simulations are described in detail in order to demonstrate the effectiveness of computationally simulating (1) complex composite structural behavior in general and (2) specific aerospace propulsion structural components in particular.

  15. Computational composite mechanics for aerospace propulsion structures

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1987-01-01

    Specialty methods are presented for the computational simulation of specific composite behavior. These methods encompass all aspects of composite mechanics, impact, progressive fracture and component specific simulation. Some of these methods are structured to computationally simulate, in parallel, the composite behavior and history from the initial frabrication through several missions and even to fracture. Select methods and typical results obtained from such simulations are described in detail in order to demonstrate the effectiveness of computationally simulating: (1) complex composite structural behavior in general, and (2) specific aerospace propulsion structural components in particular.

  16. Internally Cooled Monolithic Silicon Nitride Aerospace Components

    NASA Technical Reports Server (NTRS)

    Best, Jonathan E.; Cawley, James D.; Bhatt, Ramakrishna T.; Fox, Dennis S.; Lang, Jerry (Technical Monitor)

    2000-01-01

    A set of rapid prototyping (RP) processes have been combined with gelcasting to make ceramic aerospace components that contain internal cooling geometry. A mold and core combination is made using a MM6Pro (Sanders Prototyping, Inc.) and SLA-250/40 (3Dsystems, Inc.). The MM6Pro produces cores from ProtoBuild (trademarked) wax that are dissolved in room temperature ethanol following gelcasting. The SLA-250/40 yields epoxy/acrylate reusable molds. Parts produced by this method include two types of specimens containing a high density of thin long cooling channels, thin-walled cylinders and plates, as well as a model hollow airfoil shape that can be used for burner rig evaluation of coatings. Both uncoated and mullite-coated hollow airfoils has been tested in a Mach 0.3 burner rig with cooling air demonstrating internal cooling and confirming the effectiveness of mullite coatings.

  17. Application of fracture mechanics and half-cycle theory to the prediction of fatigue life of aerospace structural components

    NASA Technical Reports Server (NTRS)

    Ko, William L.

    1989-01-01

    The service life of aircraft structural components undergoing random stress cycling was analyzed by the application of fracture mechanics. The initial crack sizes at the critical stress points for the fatigue crack growth analysis were established through proof load tests. The fatigue crack growth rates for random stress cycles were calculated using the half-cycle method. A new equation was developed for calculating the number of remaining flights for the structural components. The number of remaining flights predicted by the new equation is much lower than that predicted by the conventional equation. This report describes the application of fracture mechanics and the half-cycle method to calculate the number of remaining flights for aircraft structural components.

  18. Automated design of aerospace structures

    NASA Technical Reports Server (NTRS)

    Fulton, R. E.; Mccomb, H. G.

    1974-01-01

    The current state-of-the-art in structural analysis of aerospace vehicles is characterized, automated design technology is discussed, and an indication is given of the future direction of research in analysis and automated design. Representative computer programs for analysis typical of those in routine use in vehicle design activities are described, and results are shown for some selected analysis problems. Recent and planned advances in analysis capability are indicated. Techniques used to automate the more routine aspects of structural design are discussed, and some recently developed automated design computer programs are described. Finally, discussion is presented of early accomplishments in interdisciplinary automated design systems, and some indication of the future thrust of research in this field is given.

  19. Soft impacts on aerospace structures

    NASA Astrophysics Data System (ADS)

    Abrate, Serge

    2016-02-01

    This article provides an overview of the literature dealing with three types of soft impacts of concern for the aerospace applications, namely impacts of rain drops, hailstones and birds against aircraft. It describes the physics of the problem as it has become better understood through experiments, analyses, and numerical simulations. Some emphasis has been placed on the material models and the numerical approaches used in modeling these three types of projectiles.

  20. NASA-UVa light aerospace alloy and structures technology program

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Stoner, Glenn E.; Swanson, Robert E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

    1991-01-01

    The general objective of the NASA-UVa Light Aerospace Alloy and Structures Technology Program was to conduct research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures. The following research areas were actively investigated: (1) mechanical and environmental degradation mechanisms in advanced light metals and composites; (2) aerospace materials science; (3) mechanics of materials and composites for aerospace structures; and (4) thermal gradient structures.

  1. Alternative Solvents and Technologies for Precision Cleaning of Aerospace Components

    NASA Technical Reports Server (NTRS)

    Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Hintze, Paul

    2014-01-01

    Precision cleaning solvents for aerospace components and oxygen fuel systems, including currently used Vertrel-MCA, have a negative environmental legacy, high global warming potential, and have polluted cleaning sites. Thus, alternative solvents and technologies are being investigated with the aim of achieving precision contamination levels of less than 1 mg/sq ft. The technologies being evaluated are ultrasonic bath cleaning, plasma cleaning and supercritical carbon dioxide cleaning.

  2. Interdisciplinary optimum design. [of aerospace structures

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

    1986-01-01

    Problems related to interdisciplinary interactions in the design of a complex engineering systems are examined with reference to aerospace applications. The interdisciplinary optimization problems examined include those dealing with controls and structures, materials and structures, control and stability, structure and aerodynamics, and structure and thermodynamics. The discussion is illustrated by the following specific applications: integrated aerodynamic/structural optimization of glider wing; optimization of an antenna parabolic dish structure for minimum weight and prescribed emitted signal gain; and a multilevel optimization study of a transport aircraft.

  3. Structural Optimization of Conceptual Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Hrinda, Glenn Andrew

    2008-01-01

    Aerospace vehicle structures must be optimized for mass to maximize the mission payload. During the conceptual design phase, structures must be optimized to accurately predict the mass of the design. Analysis methods that are used in sizing members should allow for the selection of a variety of metallic and composite materials and user-defined geometry constraints. Rapid vehicle structural analysis is often necessary to improve the fidelity and the results that are obtained during the preliminary design. Recent experiences are highlighted that utilize the Collier Research Corporation's Hypersizer toolset to optimize structural concepts.

  4. Fiber optic smart structures for aerospace applications

    NASA Astrophysics Data System (ADS)

    Udd, Eric

    Fiber optic smart structures as applied to aerospace platforms are reviewed. Emphasis is placed on advantages of these structures which include weight saving for equivalent performance, immunity to electromagnetic interference, the ability to multiplex a number of fiber optic sensors along a single line, the inherent high bandwidth of fiber optic sensors and the data links supporting them, the ability to perform in extremely hostile environments at high temperatures, vibration, and shock loadings. It is concluded that fiber optic smart structures have a considerable potential to enhance the value of future aircraft and spacecraft through improved reliability, maintainability, and flight performance augmentation.

  5. Structural Health Management for Future Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Allison, S. G.; Woodard, S. E.; Wincheski, R. A.; Cooper, E. G.; Price, D. C.; Hedley, M.; Prokopenko, M.; Scott, D. A.; Tessler, A.

    2004-01-01

    Structural Health Management (SHM) will be of critical importance to provide the safety, reliability and affordability necessary for the future long duration space missions described in America's Vision for Space Exploration. Long duration missions to the Moon, Mars and beyond cannot be accomplished with the current paradigm of periodic, ground based structural integrity inspections. As evidenced by the Columbia tragedy, this approach is also inadequate for the current Shuttle fleet, thus leading to its initial implementation of on-board SHM sensing for impact detection as part of the return to flight effort. However, future space systems, to include both vehicles as well as structures such as habitation modules, will require an integrated array of onboard in-situ sensing systems. In addition, advanced data systems architectures will be necessary to communicate, store and process massive amounts of SHM data from large numbers of diverse sensors. Further, improved structural analysis and design algorithms will be necessary to incorporate SHM sensing into the design and construction of aerospace structures, as well as to fully utilize these sensing systems to provide both diagnosis and prognosis of structural integrity. Ultimately, structural integrity information will feed into an Integrated Vehicle Health Management (IVHM) system that will provide real-time knowledge of structural, propulsion, thermal protection and other critical systems for optimal vehicle management and mission control. This paper will provide an overview of NASA research and development in the area of SHM as well as to highlight areas of technology improvement necessary to meet these future mission requirements.

  6. Progress in patch repair of aerospace composite structures

    NASA Astrophysics Data System (ADS)

    Hou, Weiguo; Zhang, Weifang; Tang, Qingyun

    2011-11-01

    With the rapid application of the composite structure in the aerospace industry, more load-bearing structures and components are used with composites instead of conventional engineering materials. However, the composite structures are inevitably suffered damages in the complex environment, the composites structures repair become more important in the airplane maintenance. This paper describes the composites patch repair progress. Firstly, the flaws and damages concerned to composite structures are concluded, and also the repair principles are presented. Secondly, the advantages and disadvantages for different repair methods are analyzed, as well as the different bonded repair and their applicability to different structures is discussed. According the recent research in theory and experiment, the scarf repair effects under different parameters are analyzed. Finally, the failure mechanisms of repair structure are discussed, and some prospects are put forward.

  7. Progress in patch repair of aerospace composite structures

    NASA Astrophysics Data System (ADS)

    Hou, Weiguo; Zhang, Weifang; Tang, Qingyun

    2012-04-01

    With the rapid application of the composite structure in the aerospace industry, more load-bearing structures and components are used with composites instead of conventional engineering materials. However, the composite structures are inevitably suffered damages in the complex environment, the composites structures repair become more important in the airplane maintenance. This paper describes the composites patch repair progress. Firstly, the flaws and damages concerned to composite structures are concluded, and also the repair principles are presented. Secondly, the advantages and disadvantages for different repair methods are analyzed, as well as the different bonded repair and their applicability to different structures is discussed. According the recent research in theory and experiment, the scarf repair effects under different parameters are analyzed. Finally, the failure mechanisms of repair structure are discussed, and some prospects are put forward.

  8. Prediction of residual strength of impact damaged aerospace composite structures

    SciTech Connect

    Garg, A.C.

    1993-12-31

    The importance of composites for aerospace structures is well known and therefore its increased use is being made for such structural components. However, these structures may be damaged as a result of various causes. One of the important causes is the impact damage either during manufacture or service. The amount of damage by impact created in the structure depends on several parameters such as impactor mass and velocity (impact energy), the structure material and support conditions. Since the magnitude of damage depends on impact energy, the residual strength may be expressed as a function of impact energy. Using a three parametric approach, a model is proposed to predict the residual strength behavior of impact damaged structure. The predicted behavior is shown to compare favorably with the available test data.

  9. Information processing for aerospace structural health monitoring

    NASA Astrophysics Data System (ADS)

    Lichtenwalner, Peter F.; White, Edward V.; Baumann, Erwin W.

    1998-06-01

    Structural health monitoring (SHM) technology provides a means to significantly reduce life cycle of aerospace vehicles by eliminating unnecessary inspections, minimizing inspection complexity, and providing accurate diagnostics and prognostics to support vehicle life extension. In order to accomplish this, a comprehensive SHM system will need to acquire data from a wide variety of diverse sensors including strain gages, accelerometers, acoustic emission sensors, crack growth gages, corrosion sensors, and piezoelectric transducers. Significant amounts of computer processing will then be required to convert this raw sensor data into meaningful information which indicates both the diagnostics of the current structural integrity as well as the prognostics necessary for planning and managing the future health of the structure in a cost effective manner. This paper provides a description of the key types of information processing technologies required in an effective SHM system. These include artificial intelligence techniques such as neural networks, expert systems, and fuzzy logic for nonlinear modeling, pattern recognition, and complex decision making; signal processing techniques such as Fourier and wavelet transforms for spectral analysis and feature extraction; statistical algorithms for optimal detection, estimation, prediction, and fusion; and a wide variety of other algorithms for data analysis and visualization. The intent of this paper is to provide an overview of the role of information processing for SHM, discuss various technologies which can contribute to accomplishing this role, and present some example applications of information processing for SHM implemented at the Boeing Company.

  10. Smart electronics and MEMS for aerospace structures

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1995-09-01

    In this paper, smart electronics and MEMS are employed to sense and control the drag in aircraft structures. The sensors are fabricated with interdigital transducers printed on a piezoelectric polymer. They in turn are mounted onto an ultra thin Penn State's novel RF antenna (Patent field). The sensor are designed to measure both pressure and shear of the fluid flow on aerospace structures. The wave form measurements may be monitored at a remote location either at the cockpit or elsewhere via the antennas in the sensors and an outside antenna. The integrated MEMS actuators which comprise of cantilever-, diaphram- and microbridge-based MEMS with suitable smart electronics etched onto the structure are controlled by the built-in antennas through feedback and feedforward control architecture. The integration of such materials and smart electronics into the skin of airfoil is ideal for sensing and controlling drag. The basic idea of this concept involves detection of the point of transition from laminar to turbulent flow and transmitting acoustical energy into the boundary layer so that the low energy fluid particles accelerate in the transverse direction and mix with the high energy flow outside of the boundary layer. 3D microriblets can be fabricated using stereo lithography and UV curable conducting polymers. The control of drag using these active microriblets are outlined.

  11. Development of components for waste management systems using aerospace technology

    SciTech Connect

    Rousar, D.; Young, M.; Sieger, A.

    1995-09-01

    An aerospace fluid management technology called ``platelets`` has been applied to components that are critical to the economic operation of waste management systems. Platelet devices are made by diffusion bonding thin metal plates which have been etched with precise flow passage circuitry to control and meter fluid to desired locations. Supercritical water oxidation (SCWO) is a promising waste treatment technology for safe and environmentally acceptable destruction of hazardous wastes. Performance and economics of current SCWO systems are limited by severe salt deposition on and corrosion of the reactor walls. A platelet transpiring-wall reactor has been developed that provides a protective layer of water adjacent to the reactor walls which prevents salt deposition and corrosion. Plasma arc processing is being considered as a method for stabilizing mixed radioactive wastes. Plasma arc torch systems currently require frequent shutdown to replace failed electrodes and this increases operating costs. A platelet electrode design was developed that has more than 10 times the life of conventional electrodes. It has water cooling channels internal to the electrode wall and slots through the wall for injecting gas into the arc.

  12. Electronic Components for use in Extreme Temperature Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Electrical power management and control systems designed for use in planetary exploration missions and deep space probes require electronics that are capable of efficient and reliable operation under extreme temperature conditions. Space-based infra-red satellites, all-electric ships, jet engines, electromagnetic launchers, magnetic levitation transport systems, and power facilities are also typical examples where the electronics are expected to be exposed to harsh temperatures and to operate under severe thermal swings. Most commercial-off-the-shelf (COTS) devices are not designed to function under such extreme conditions and, therefore, new parts must be developed or the conventional devices need to be modified. For example, spacecraft operating in the cold environment of deep space carry a large number of radioisotope heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 C. At the other end, built-in radiators and coolers render the operation of electronics possible under hot conditions. These thermal measures lead to design complexity, affect development costs, and increase size and weight. Electronics capable of operation at extreme temperatures, thus, will not only tolerate the hostile operational environment, but also make the overall system efficient, more reliable, and less expensive. The Extreme Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electronics suitable for applications in the aerospace environment and deep space exploration missions. Research is being conducted on devices, including COTS parts, for potential use under extreme temperatures. These components include semiconductor switching devices, passive devices, DC/DC converters, operational amplifiers, and oscillators. An overview of the program will be presented along with some experimental findings.

  13. A review of multifunctional structure technology for aerospace applications

    NASA Astrophysics Data System (ADS)

    Sairajan, K. K.; Aglietti, G. S.; Mani, K. M.

    2016-03-01

    The emerging field of multifunctional structure (MFS) technologies enables the design of systems with reduced mass and volume, thereby improving their overall efficiency. It requires developments in different engineering disciplines and their integration into a single system without degrading their individual performances. MFS is particularly suitable for aerospace applications where mass and volume are critical to the cost of the mission. This article reviews the current state of the art of multifunctional structure technologies relevant to aerospace applications.

  14. Lessons learned from modal testing of aerospace structures

    NASA Astrophysics Data System (ADS)

    Hunt, David L.; Brillhart, Ralph D.

    1993-02-01

    The primary factors affecting the accuracy and the time required to perform modal tests on aerospace structures are discussed, and the lessons learned from modal tests performed over the past 15 yrs are examined. Case histories of modal testing on aerospace structures are reviewed, including the Galileo satellite and the Space Shuttle solid rocket motor and test stand. Currently recommended approaches to the modal testing are addressed.

  15. NASA-UVA light aerospace alloy and structures technology program

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Stoner, Glenn E.; Swanson, Robert E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1990-01-01

    The objective of the Light Aerospace Alloy and Structures Technology Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures. Individual technical objectives are established for each project. Efforts aim to produce basic understanding of material behavior, monolithic and composite alloys, processing methods, solid and mechanics analyses, measurement advances, and a pool of educated graduate students. Progress is reported for 11 areas of study.

  16. Automated metrology and NDE measurements for increased throughput in aerospace component manufacture

    NASA Astrophysics Data System (ADS)

    MacLeod, Charles N.; Pierce, S. Gareth; Morozov, Maxim; Summan, Rahul; Dobie, Gordon; McCubbin, Paul; McCubbin, Coreen; Dearie, Scott; Munro, Gavin

    2015-03-01

    Composite materials, particularly Carbon-Fibre-Reinforced Polymer (CFRP), find extensive use in construction of modern airframe structures. Quality and conformance checks can be a serious limitation on production throughput in aerospace manufacturing. Traditionally Non-Destructive Evaluation (NDE) and metrology measurements are undertaken at different stages of a product manufacture cycle using specific dedicated equipment and personnel. However, since both processes involve direct interaction with the component's surface, an opportunity exists to combine these to potentially reduce overall cycle time. In addition when considering moves towards automation of both inspection processes, it is clear that measured metrology data is an essential input parameter to the automated NDE workflow. The authors present the findings of a proof of concept combined sub-scale NDE and Metrology demonstrator cell for aerospace components. Permitting a maximum part area size of 3 × 1 m2, KUKA KR5 6 degree of freedom robotic manipulators were utilised to deploy two inspection payloads. Firstly automated non-contact photogrammetric metrology measurement was employed to inspect the structure for conformance of dimension in relation to reference designs (available from CAD). Secondly automated phased array technology was deployed to inspect and produce ultrasonic thickness mapping of components of nominal 20mm thickness. Parameters such as overall cycle time, part dimensional accuracy, robotic path accuracy and data registration are assessed in the paper to highlight both the current state of the art performance available and the future direction of required research focus.

  17. Challenges for Insertion of Structural Nanomaterials in Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Sochi, Emilie J.

    2012-01-01

    In the two decades since Iijima's report on carbon nanotubes (CNT), there has been great interest in realizing the benefits of mechanical properties observed at the nanoscale in large-scale structures. The weight savings possible due to dramatic improvements in mechanical properties relative to state-of-the-art material systems can be game changing for applications like aerospace vehicles. While there has been significant progress in commercial production of CNTs, major aerospace applications that take advantage of properties offered by this material have yet to be realized. This paper provides a perspective on the technical challenges and barriers for insertion of CNTs as an emerging material technology in aerospace applications and proposes approaches that may reduce the typical timeframe for technology maturation and insertion into aerospace structures.

  18. Advances in Computational Stability Analysis of Composite Aerospace Structures

    SciTech Connect

    Degenhardt, R.; Araujo, F. C. de

    2010-09-30

    European aircraft industry demands for reduced development and operating costs. Structural weight reduction by exploitation of structural reserves in composite aerospace structures contributes to this aim, however, it requires accurate and experimentally validated stability analysis of real structures under realistic loading conditions. This paper presents different advances from the area of computational stability analysis of composite aerospace structures which contribute to that field. For stringer stiffened panels main results of the finished EU project COCOMAT are given. It investigated the exploitation of reserves in primary fibre composite fuselage structures through an accurate and reliable simulation of postbuckling and collapse. For unstiffened cylindrical composite shells a proposal for a new design method is presented.

  19. Frequency Response Function Based Damage Identification for Aerospace Structures

    NASA Astrophysics Data System (ADS)

    Oliver, Joseph Acton

    Structural health monitoring technologies continue to be pursued for aerospace structures in the interests of increased safety and, when combined with health prognosis, efficiency in life-cycle management. The current dissertation develops and validates damage identification technology as a critical component for structural health monitoring of aerospace structures and, in particular, composite unmanned aerial vehicles. The primary innovation is a statistical least-squares damage identification algorithm based in concepts of parameter estimation and model update. The algorithm uses frequency response function based residual force vectors derived from distributed vibration measurements to update a structural finite element model through statistically weighted least-squares minimization producing location and quantification of the damage, estimation uncertainty, and an updated model. Advantages compared to other approaches include robust applicability to systems which are heavily damped, large, and noisy, with a relatively low number of distributed measurement points compared to the number of analytical degrees-of-freedom of an associated analytical structural model (e.g., modal finite element model). Motivation, research objectives, and a dissertation summary are discussed in Chapter 1 followed by a literature review in Chapter 2. Chapter 3 gives background theory and the damage identification algorithm derivation followed by a study of fundamental algorithm behavior on a two degree-of-freedom mass-spring system with generalized damping. Chapter 4 investigates the impact of noise then successfully proves the algorithm against competing methods using an analytical eight degree-of-freedom mass-spring system with non-proportional structural damping. Chapter 5 extends use of the algorithm to finite element models, including solutions for numerical issues, approaches for modeling damping approximately in reduced coordinates, and analytical validation using a composite

  20. Probabilistic evaluation of uncertainties and risks in aerospace components

    NASA Technical Reports Server (NTRS)

    Shah, A. R.; Shiao, M. C.; Nagpal, V. K.; Chamis, C. C.

    1992-01-01

    This paper summarizes a methodology developed at NASA Lewis Research Center which computationally simulates the structural, material, and load uncertainties associated with Space Shuttle Main Engine (SSME) components. The methodology was applied to evaluate the scatter in static, buckling, dynamic, fatigue, and damage behavior of the SSME turbo pump blade. Also calculated are the probability densities of typical critical blade responses, such as effective stress, natural frequency, damage initiation, most probable damage path, etc. Risk assessments were performed for different failure modes, and the effect of material degradation on the fatigue and damage behaviors of a blade were calculated using a multi-factor interaction equation. Failure probabilities for different fatigue cycles were computed and the uncertainties associated with damage initiation and damage propagation due to different load cycle were quantified. Evaluations on the effects of mistuned blades on a rotor were made; uncertainties in the excitation frequency were found to significantly amplify the blade responses of a mistuned rotor. The effects of the number of blades on a rotor were studied. The autocorrelation function of displacements and the probability density function of the first passage time for deterministic and random barriers for structures subjected to random processes also were computed. A brief discussion was included on the future direction of probabilistic structural analysis.

  1. Probabilistic evaluation of uncertainties and risks in aerospace components

    NASA Astrophysics Data System (ADS)

    Shah, A. R.; Shiao, M. C.; Nagpal, V. K.; Chamis, C. C.

    1992-03-01

    This paper summarizes a methodology developed at NASA Lewis Research Center which computationally simulates the structural, material, and load uncertainties associated with Space Shuttle Main Engine (SSME) components. The methodology was applied to evaluate the scatter in static, buckling, dynamic, fatigue, and damage behavior of the SSME turbo pump blade. Also calculated are the probability densities of typical critical blade responses, such as effective stress, natural frequency, damage initiation, most probable damage path, etc. Risk assessments were performed for different failure modes, and the effect of material degradation on the fatigue and damage behaviors of a blade were calculated using a multi-factor interaction equation. Failure probabilities for different fatigue cycles were computed and the uncertainties associated with damage initiation and damage propagation due to different load cycle were quantified. Evaluations on the effects of mistuned blades on a rotor were made; uncertainties in the excitation frequency were found to significantly amplify the blade responses of a mistuned rotor. The effects of the number of blades on a rotor were studied. The autocorrelation function of displacements and the probability density function of the first passage time for deterministic and random barriers for structures subjected to random processes also were computed. A brief discussion was included on the future direction of probabilistic structural analysis.

  2. Research and Development of Rapid Design Systems for Aerospace Structure

    NASA Technical Reports Server (NTRS)

    Schaeffer, Harry G.

    1999-01-01

    This report describes the results of research activities associated with the development of rapid design systems for aerospace structures in support of the Intelligent Synthesis Environment (ISE). The specific subsystems investigated were the interface between model assembly and analysis; and, the high performance NASA GPS equation solver software system in the Windows NT environment on low cost high-performance PCs.

  3. Recent advancement in optical fiber sensing for aerospace composite structures

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Takeda, Nobuo

    2013-12-01

    Optical fiber sensors have attracted considerable attention in health monitoring of aerospace composite structures. This paper briefly reviews our recent advancement mainly in Brillouin-based distributed sensing. Damage detection, life cycle monitoring and shape reconstruction systems applicable to large-scale composite structures are presented, and new technical concepts, "smart crack arrester" and "hierarchical sensing system", are described as well, highlighting the great potential of optical fiber sensors for the structural health monitoring (SHM) field.

  4. Approaches to hybrid SHM and NDE of composite aerospace structures

    NASA Astrophysics Data System (ADS)

    Michaels, Jennifer E.; Dawson, Alexander J.; Michaels, Thomas E.; Ruzzene, Massimo

    2014-03-01

    Periodic inspection of aerospace structures, while essential for ensuring their safety, incurs significant costs over a structure's life and also can result in significant loss of service. Structural health monitoring (SHM), which is also referred to as in situ nondestructive evaluation (NDE), offers the promise of more frequent assessments of structural integrity with little or no loss of service; however, such systems are not in common use. Here we consider a combined SHM and NDE approach to inspection of composite, plate-like components where the SHM system detects sites of possible damage and the follow-up NDE method utilizes the in situ SHM sensors to facilitate the inspection. The specific SHM approach considered is that of a sparse guided wave array using simple transducers that are spatially distributed on the structure. The NDE approach is non-contact guided wavefield imaging whereby one or more of the SHM transducers is used as a source and full wavefield data are recorded over the area of interest. This method has the advantage over conventional ultrasonic methods of being non-contact and requiring minimal surface preparation. Sparse array and wavefield data from a composite specimen with simulated sites of damage are presented here to illustrate the concept. Damage is simulated via glued-on steel plate pieces at multiple locations, and localization is performed using delay-and-sum imaging. A small, single site of simulated damage is well-localized, whereas larger and multiple sites of damage are not; however, their presence is readily detected. The follow-up wavefield imaging using a single sparse array transducer as a source is able to not only locate the sites of damage, but is able to provide a reasonable estimate of their sizes.

  5. The pultrusion process for structures on advanced aerospace transportation systems

    NASA Technical Reports Server (NTRS)

    Wilson, Maywood L.; Macconochie, Ian O.; Johnson, Gary S.

    1986-01-01

    The pultrusion process, which has the potential for use in the manufacture of structures for aerospace hardware, is described. In this process, reinforcing fibers are pulled continuously through a resin system for wetting and subsequently through a heated die for polymerization. By using this process, fabrication of very long lengths of high strength, lightweight structures with consistently high quality for aerospace applications is possible. The more conventional processes involve hand lay-up, vacuum bagging, autoclaving or oven curing techniques such that lengths of structural elements produced are limited by the lengths of autoclaves or curing ovens. Several types of developmental structural elements are described in which fiberglass, aramid, graphite, and hybrid fiber systems have been used as reinforcements in an epoxy matrix and their flexural properties compared. Reinforcement fibers having tailor-made orientations which achieve tailor-made strength in the pultrusions are described. The potential aerospace applications for the pultruded products are described with advantages cited over conventional hand lay-up methods.

  6. Validation of Commercial Fiber Optic Components for Aerospace Environments

    NASA Technical Reports Server (NTRS)

    Ott, Melanie N.

    2005-01-01

    Full qualification for commercial photonic parts as defined by the Military specification system in the past, is not feasible. Due to changes in the photonic components industry and the Military specification system that NASA had relied upon so heavily in the past, an approach to technology validation of commercial off the shelf parts had to be devised. This approach involves knowledge of system requirements, environmental requirements and failure modes of the particular components under consideration. Synthesizing the criteria together with the major known failure modes to formulate a test plan is an effective way of establishing knowledge based "qualification". Although this does not provide the type of reliability assurance that the Military specification system did in the past, it is an approach that allows for increased risk mitigation. The information presented will introduce the audience to the technology validation approach that is currently applied at NASA for the usage of commercial-off-the-shelf (COTS) fiber optic components for space flight environments. The focus will be on how to establish technology validation criteria for commercial fiber products such that continued reliable performance is assured under the harsh environmental conditions of typical missions. The goal of this presentation is to provide the audience with an approach to formulating a COTS qualification test plan for these devices. Examples from past NASA missions will be discussed.

  7. Stochastic Simulation Tool for Aerospace Structural Analysis

    NASA Technical Reports Server (NTRS)

    Knight, Norman F.; Moore, David F.

    2006-01-01

    Stochastic simulation refers to incorporating the effects of design tolerances and uncertainties into the design analysis model and then determining their influence on the design. A high-level evaluation of one such stochastic simulation tool, the MSC.Robust Design tool by MSC.Software Corporation, has been conducted. This stochastic simulation tool provides structural analysts with a tool to interrogate their structural design based on their mathematical description of the design problem using finite element analysis methods. This tool leverages the analyst's prior investment in finite element model development of a particular design. The original finite element model is treated as the baseline structural analysis model for the stochastic simulations that are to be performed. A Monte Carlo approach is used by MSC.Robust Design to determine the effects of scatter in design input variables on response output parameters. The tool was not designed to provide a probabilistic assessment, but to assist engineers in understanding cause and effect. It is driven by a graphical-user interface and retains the engineer-in-the-loop strategy for design evaluation and improvement. The application problem for the evaluation is chosen to be a two-dimensional shell finite element model of a Space Shuttle wing leading-edge panel under re-entry aerodynamic loading. MSC.Robust Design adds value to the analysis effort by rapidly being able to identify design input variables whose variability causes the most influence in response output parameters.

  8. Development of Structural Health Management Technology for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.

    2003-01-01

    As part of the overall goal of developing Integrated Vehicle Health Management (IVHM) systems for aerospace vehicles, NASA has focused considerable resources on the development of technologies for Structural Health Management (SHM). The motivations for these efforts are to increase the safety and reliability of aerospace structural systems, while at the same time decreasing operating and maintenance costs. Research and development of SHM technologies has been supported under a variety of programs for both aircraft and spacecraft including the Space Launch Initiative, X-33, Next Generation Launch Technology, and Aviation Safety Program. The major focus of much of the research to date has been on the development and testing of sensor technologies. A wide range of sensor technologies are under consideration including fiber-optic sensors, active and passive acoustic sensors, electromagnetic sensors, wireless sensing systems, MEMS, and nanosensors. Because of their numerous advantages for aerospace applications, most notably being extremely light weight, fiber-optic sensors are one of the leading candidates and have received considerable attention.

  9. Computational technology for high-temperature aerospace structures

    NASA Technical Reports Server (NTRS)

    Noor, A. K.; Card, M. F.

    1992-01-01

    The status and some recent developments of computational technology for high-temperature aerospace structures are summarized. Discussion focuses on a number of aspects including: goals of computational technology for high-temperature structures; computational material modeling; life prediction methodology; computational modeling of high-temperature composites; error estimation and adaptive improvement strategies; strategies for solution of fluid flow/thermal/structural problems; and probabilistic methods and stochastic modeling approaches, integrated analysis and design. Recent trends in high-performance computing environment are described and the research areas which have high potential for meeting future technological needs are identified.

  10. Capacitance-based damage detection sensing for aerospace structural composites

    NASA Astrophysics Data System (ADS)

    Bahrami, P.; Yamamoto, N.; Chen, Y.; Manohara, H.

    2014-04-01

    Damage detection technology needs improvement for aerospace engineering application because detection within complex composite structures is difficult yet critical to avoid catastrophic failure. Damage detection is challenging in aerospace structures because not all the damage detection technology can cover the various defect types (delamination, fiber fracture, matrix crack etc.), or conditions (visibility, crack length size, etc.). These defect states are expected to become even more complex with future introduction of novel composites including nano-/microparticle reinforcement. Currently, non-destructive evaluation (NDE) methods with X-ray, ultrasound, or eddy current have good resolutions (< 0.1 mm), but their detection capabilities is limited by defect locations and orientations and require massive inspection devices. System health monitoring (SHM) methods are often paired with NDE technologies to signal out sensed damage, but their data collection and analysis currently requires excessive wiring and complex signal analysis. Here, we present a capacitance sensor-based, structural defect detection technology with improved sensing capability. Thin dielectric polymer layer is integrated as part of the structure; the defect in the structure directly alters the sensing layer's capacitance, allowing full-coverage sensing capability independent of defect size, orientation or location. In this work, capacitance-based sensing capability was experimentally demonstrated with a 2D sensing layer consisting of a dielectric layer sandwiched by electrodes. These sensing layers were applied on substrate surfaces. Surface indentation damage (~1mm diameter) and its location were detected through measured capacitance changes: 1 to 250 % depending on the substrates. The damage detection sensors are light weight, and they can be conformably coated and can be part of the composite structure. Therefore it is suitable for aerospace structures such as cryogenic tanks and rocket

  11. Nonlinear analyses of composite aerospace structures in sonic fatigue

    NASA Technical Reports Server (NTRS)

    Mei, Chuh

    1992-01-01

    The primary research effort of this project is the development of analytical methods for the prediction of nonlinear random response of composite aerospace structures subjected to combined acoustic and thermal loads. The progress, accomplishments, and future plans of three random response research topics are discussed, namely acoustics-structure interactions using boundary/finite element methods, nonlinear vibrations of beams and composite plates under harmonic and random excitations, and numerical simulation of the nonlinear response of composite plates under combined thermal and acoustic loading.

  12. Structural health management of aerospace hotspots under fatigue loading

    NASA Astrophysics Data System (ADS)

    Soni, Sunilkumar

    Sustainability and life-cycle assessments of aerospace systems, such as aircraft structures and propulsion systems, represent growing challenges in engineering. Hence, there has been an increasing demand in using structural health monitoring (SHM) techniques for continuous monitoring of these systems in an effort to improve safety and reduce maintenance costs. The current research is part of an ongoing multidisciplinary effort to develop a robust SHM framework resulting in improved models for damage-state awareness and life prediction, and enhancing capability of future aircraft systems. Lug joints, a typical structural hotspot, were chosen as the test article for the current study. The thesis focuses on integrated SHM techniques for damage detection and characterization in lug joints. Piezoelectric wafer sensors (PZTs) are used to generate guided Lamb waves as they can be easily used for onboard applications. Sensor placement in certain regions of a structural component is not feasible due to the inaccessibility of the area to be monitored. Therefore, a virtual sensing concept is introduced to acquire sensor data from finite element (FE) models. A full three dimensional FE analysis of lug joints with piezoelectric transducers, accounting for piezoelectrical-mechanical coupling, was performed in Abaqus and the sensor signals were simulated. These modeled sensors are called virtual sensors. A combination of real data from PZTs and virtual sensing data from FE analysis is used to monitor and detect fatigue damage in aluminum lug joints. Experiments were conducted on lug joints under fatigue loads and sensor signals collected were used to validate the simulated sensor response. An optimal sensor placement methodology for lug joints is developed based on a detection theory framework to maximize the detection rate and minimize the false alarm rate. The placement technique is such that the sensor features can be directly correlated to damage. The technique accounts for a

  13. Nonlinear analyses of composite aerospace structures in sonic fatigue

    NASA Technical Reports Server (NTRS)

    Mei, Chuh

    1993-01-01

    This report summarizes the semiannual research progress, accomplishments, and future plans performed under the NASA Langley Research Center Grant No. NAG-1-1358. The primary research effort of this project is the development of analytical methods for the prediction of nonlinear random response of composite aerospace structures subjected to combined acoustic and thermal loads. The progress, accomplishments, and future plates on four sonic fatigue research topics are described. The sonic fatigue design and passive control of random response of shape memory alloy hybrid composites presented in section 4, which is suited especially for HSCT, is a new initiative.

  14. Some aspects of algorithm performance and modeling in transient thermal analysis of structures. [aerospace vehicle structures

    NASA Technical Reports Server (NTRS)

    Adelman, H. M.; Haftka, R. T.; Robinson, J. C.

    1982-01-01

    The status of an effort to increase the efficiency of calculating transient temperature fields in complex aerospace vehicle structures is described. The advantages and disadvantages of explicit and implicit algorithms are discussed. A promising set of implicit algorithms with variable time steps, known as the GEAR package is described. Four test problems, used for evaluating and comparing various algorithms, were selected and finite element models of the configurations are described. These problems include a space shuttle frame component, an insulated cylinder, a metallic panel for a thermal protection system, and a model of the space shuttle orbiter wing. Results generally indicate a preference for implicit oer explicit algorithms for solution of transient structural heat transfer problems when the governing equations are stiff.

  15. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  16. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1982-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons and methods for making such materials. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  17. Structural materials and components

    NASA Technical Reports Server (NTRS)

    Gagliani, John (Inventor); Lee, Raymond (Inventor)

    1983-01-01

    High density structural (blocking) materials composed of a polyimide filled with glass microballoons. Structural components such as panels which have integral edgings and/or other parts made of the high density materials.

  18. Health monitoring studies on composite structures for aerospace applications

    SciTech Connect

    James, G.; Roach, D.; Hansche, B.; Meza, R.; Robinson, N.

    1996-02-01

    This paper discusses ongoing work to develop structural health monitoring techniques for composite aerospace structures such as aircraft control surfaces, fuselage sections or repairs, and reusable launch vehicle fuel tanks. The overall project is divided into four tasks: Operational evaluation, diagnostic measurements, information condensation, and damage detection. Five composite plates were constructed to study delaminations, disbonds, and fluid retention issues as the initial step in creating an operational system. These four square feet plates were graphite-epoxy with nomex honeycomb cores. The diagnostic measurements are composed of modal tests with a scanning laser vibrometer at over 500 scan points per plate covering the frequency range up to 2000 Hz. This data has been reduced into experimental dynamics matrices using a generic, software package developed at the University of Colorado at Boulder. The continuing effort will entail performing a series of damage identification studies to detect, localize, and determine the extent of the damage. This work is providing understanding and algorithm development for a global NDE technique for composite aerospace structures.

  19. NASA-UVA light aerospace alloy and structures technology program

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Thornton, Earl A.; Stoner, Glenn E.; Swanson, Robert E.; Wawner, Franklin E., Jr.; Wert, John A.

    1989-01-01

    The report on progress achieved in accomplishing of the NASA-UVA Light Aerospace Alloy and Structures Technology Program is presented. The objective is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys and associated thermal gradient structures in close collaboration with researchers. The efforts will produce basic understanding of material behavior, new monolithic and composite alloys, processing methods, solid and fluid mechanics analyses, measurement advances, and a pool of educated graduate students. The presented accomplishments include: research on corrosion fatigue of Al-Li-Cu alloy 2090; research on the strengthening effect of small In additions to Al-Li-Cu alloys; research on localized corrosion of Al-Li alloys; research on stress corrosion cracking of Al-Li-Cu alloys; research on fiber-matrix reaction studies (Ti-1100 and Ti-15-3 matrices containing SCS-6, SCS-9, and SCS-10 fibers); and research on methods for quantifying non-random particle distribution in materials that has led to generation of a set of computer programs that can detect and characterize clusters in particles.

  20. 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

  1. Finite-element thermo-viscoplastic analysis of aerospace structures

    NASA Technical Reports Server (NTRS)

    Pandey, Ajay; Dechaumphai, Pramote; Thornton, Earl A.

    1990-01-01

    The time-dependent thermo-viscoplastic response of aerospace structures subjected to intense aerothermal loads is predicted using the finite-element method. The finite-element analysis uses the Bodner-Partom unified viscoplastic constitutive relations to determine rate-dependent nonlinear material behavior. The methodology is verified by comparison with experimental data and other numerical results for a uniaxially-loaded bar. The method is then used (1) to predict the structural response of a rectangular plate subjected to line heating along a centerline, and (2) to predict the thermal-structural response of a convectively-cooled engine cowl leading edge subjected to aerodynamic shock-shock interference heating. Compared to linear elastic analysis, the viscoplastic analysis results in lower peak stresses and regions of plastic deformations.

  2. Finite element thermo-viscoplastic analysis of aerospace structures

    NASA Technical Reports Server (NTRS)

    Pandey, Ajay K.; Dechaumphai, Pramote; Thornton, Earl A.

    1990-01-01

    The time-dependent thermo-viscoplastic response of aerospace structures subjected to intense aerothermal loads is predicted using the finite-element method. The finite-element analysis uses the Bodner-Partom unified viscoplastic constitutive relations to determine rate-dependent nonlinear material behavior. The methodology is verified by comparison with experimental data and other numerical results for a uniaxially-loaded bar. The method is then used (1) to predict the structural response of a rectangular plate subjected to line heating along a centerline, and (2) to predict the thermal-structural response of a convectively-cooled engine cowl leading edge subjected to aerodynamic shock-shock interference heating. Compared to linear elastic analysis, the viscoplastic analysis results in lower peak stresses and regions of plastic deformations.

  3. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-03-08

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (NM) impedance technique are sighted and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency EIM impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acoustic-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens, (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  4. Active sensors for health monitoring of aging aerospace structures

    SciTech Connect

    GIURGIUTIU,VICTOR; REDMOND,JAMES M.; ROACH,DENNIS P.; RACKOW,KIRK A.

    2000-02-29

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high-frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto-ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  5. Active sensors for health monitoring of aging aerospace structures

    NASA Astrophysics Data System (ADS)

    Giurgiutiu, Victor; Redmond, James M.; Roach, Dennis P.; Rackow, Kirk

    2000-06-01

    A project to develop non-intrusive active sensors that can be applied on existing aging aerospace structures for monitoring the onset and progress of structural damage (fatigue cracks and corrosion) is presented. The state of the art in active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) electro-mechanical (E/M) impedance technique are cited and briefly discussed. The instrumentation of these specimens with piezoelectric active sensors is illustrated. The main detection strategies (E/M impedance for local area detection and wave propagation for wide area interrogation) are discussed. The signal processing and damage interpretation algorithms are tuned to the specific structural interrogation method used. In the high frequency E/M impedance approach, pattern recognition methods are used to compare impedance signatures taken at various time intervals and to identify damage presence and progression from the change in these signatures. In the wave propagation approach, the acousto- ultrasonic methods identifying additional reflection generated from the damage site and changes in transmission velocity and phase are used. Both approaches benefit from the use of artificial intelligence neural networks algorithms that can extract damage features based on a learning process. Design and fabrication of a set of structural specimens representative of aging aerospace structures is presented. Three built-up specimens, (pristine, with cracks, and with corrosion damage) are used. The specimen instrumentation with active sensors fabricated at the University of South Carolina is illustrated. Preliminary results obtained with the E/M impedance method on pristine and cracked specimens are presented.

  6. Reduction method for thermal analysis of complex aerospace structures

    NASA Technical Reports Server (NTRS)

    Shore, C. P.

    1985-01-01

    A reduction method which combines classical Rayleigh-Ritz modal superposition techniques with contemporary finite-element methods is applied to transient nonlinear thermal analysis of aerospace structures. The essence of the method is the use of a few thermal modes from eigenvalue analyses as basis vectors to represent the temperature response in the structure. The method is used to obtain approximate temperature histories for a portion of the Shuttle orbiter wing subject to reentry heating and for a large space antenna reflector subject to heating associated with a low Earth orbit. The reduction method has excellent potential for significant size reduction for radiation-dominated problems such as the antenna reflector. However, for conduction-dominated problems such as the Shuttle wing, especially those with complex spatial and temporal variations in the applied heating, additional work appears necessary to find alternate sources of basis vectors which will permit significant problem size reductions.

  7. Intercalated graphite fiber composites as EMI shields in aerospace structures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1990-01-01

    The requirements for electromagnetic interference (EMI) shielding in aerospace structures are complicated over that of ground structures by their weight limitations. As a result, the best EMI shielding materials must blend low density, high strength, and high elastic modulus with high shielding ability. In addition, fabrication considerations including penetrations and joints play a major role. The EMI shielding properties are calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compared to preliminary experimental results and to shields made from aluminum. Calculations indicate that EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding properties alone.

  8. Intercalated graphite fiber composites as EMI shields in aerospace structures

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    1992-01-01

    The requirements for electromagnetic interference (EMI) shielding in aerospace structures are more complicated than those for ground structures because of their weight limitations. As a result, the best EMI shielding materials must combine low density, high strength, and high elastic modulus with high shielding ability. EMI shielding characteristics were calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compare to preliminary experimental results for these materials and to the characteristics of shields made from aluminum. Calculations indicate that effective EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding characteristics alone.

  9. System design for active vibration control of aerospace structures

    NASA Astrophysics Data System (ADS)

    Shankar, V.; Nagaraja, B. V.; Balasubramaniam, R.; Shree S, Amrutha; Muthaiah, Skanda N.

    2003-10-01

    Instrumentation, electronics, digital signal processing and related software form the basic building blocks of a system for implementation of Active Vibration Control (AVC) for smart aerospace structures. This paper essentially deals with the design, development and implementation of a 4 channel analog input sub-system essentially consisting of charge amplifiers, filters, gain amplifiers & Analog to Digital Converters (ADC), the subsequent Digital Signal Processor (DSP) hardware for implementation of the controller and finally a 4 Channel analog output subsystem consisting of Digital to Analog Converters (DAC), reconstruction filters & high voltage amplifiers. This system essentially interfaces to a structure with piezo-ceramic sensors and actuators for implementation of real time AVC on a smart beam. The paper also highlights some of the new ideas that have been incorporated into the system design.

  10. Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Takane, Yoshio

    2004-01-01

    We propose an alternative method to partial least squares for path analysis with components, called generalized structured component analysis. The proposed method replaces factors by exact linear combinations of observed variables. It employs a well-defined least squares criterion to estimate model parameters. As a result, the proposed method…

  11. Titanium cholla : lightweight, high-strength structures for aerospace applications.

    SciTech Connect

    Atwood, Clinton J.; Voth, Thomas Eugene; Taggart, David G.; Gill, David Dennis; Robbins, Joshua H.; Dewhurst, Peter

    2007-10-01

    Aerospace designers seek lightweight, high-strength structures to lower launch weight while creating structures that are capable of withstanding launch loadings. Most 'light-weighting' is done through an expensive, time-consuming, iterative method requiring experience and a repeated design/test/redesign sequence until an adequate solution is obtained. Little successful work has been done in the application of generalized 3D optimization due to the difficulty of analytical solutions, the large computational requirements of computerized solutions, and the inability to manufacture many optimized structures with conventional machining processes. The Titanium Cholla LDRD team set out to create generalized 3D optimization routines, a set of analytically optimized 3D structures for testing the solutions, and a method of manufacturing these complex optimized structures. The team developed two new computer optimization solutions: Advanced Topological Optimization (ATO) and FlexFEM, an optimization package utilizing the eXtended Finite Element Method (XFEM) software for stress analysis. The team also developed several new analytically defined classes of optimized structures. Finally, the team developed a 3D capability for the Laser Engineered Net Shaping{trademark} (LENS{reg_sign}) additive manufacturing process including process planning for 3D optimized structures. This report gives individual examples as well as one generalized example showing the optimized solutions and an optimized metal part.

  12. Report on aerospace structures and structural materials R and D in Europe

    SciTech Connect

    Hansen, J.G.R.

    1990-10-01

    The end-of-tour report summarizes 65 leading European R and D programs encountered by the author during his assignment as Chief, Structures and Structural Materials in the USAF EOARD (European Office of Aerospace Research and Development) from 1985-1990. The report is divided into two sections: (1) Aerospace Structural Materials; and (2) Aerospace Structures and Solid Mechanics. For each of the programs, a summary of the capability is presented, contact information is provided for the principal investigator, other more detailed EOARD Liaison Reports (which can be ordered from EOARD) are referenced if they exist, and if there has been an R and D project funded by the USAF at the European organization, the name and address of the USAF project monitor is provided.

  13. Optimization of Aerospace Structure Subject to Damage Tolerance Criteria

    NASA Technical Reports Server (NTRS)

    Akgun, Mehmet A.

    1999-01-01

    The objective of this cooperative agreement was to seek computationally efficient ways to optimize aerospace structures subject to damage tolerance criteria. Optimization was to involve sizing as well as topology optimization. The work was done in collaboration with Steve Scotti, Chauncey Wu and Joanne Walsh at the NASA Langley Research Center. Computation of constraint sensitivity is normally the most time-consuming step of an optimization procedure. The cooperative work first focused on this issue and implemented the adjoint method of sensitivity computation in an optimization code (runstream) written in Engineering Analysis Language (EAL). The method was implemented both for bar and plate elements including buckling sensitivity for the latter. Lumping of constraints was investigated as a means to reduce the computational cost. Adjoint sensitivity computation was developed and implemented for lumped stress and buckling constraints. Cost of the direct method and the adjoint method was compared for various structures with and without lumping. The results were reported in two papers. It is desirable to optimize topology of an aerospace structure subject to a large number of damage scenarios so that a damage tolerant structure is obtained. Including damage scenarios in the design procedure is critical in order to avoid large mass penalties at later stages. A common method for topology optimization is that of compliance minimization which has not been used for damage tolerant design. In the present work, topology optimization is treated as a conventional problem aiming to minimize the weight subject to stress constraints. Multiple damage configurations (scenarios) are considered. Each configuration has its own structural stiffness matrix and, normally, requires factoring of the matrix and solution of the system of equations. Damage that is expected to be tolerated is local and represents a small change in the stiffness matrix compared to the baseline (undamaged

  14. NASA-UVA light aerospace alloy and structures technology program (LA(sup 2)ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Starke, Edgar A., Jr.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.

    1992-01-01

    The general objective of the Light Aerospace Alloy and Structures Technology (LA(sup 2)ST) Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with Langley researchers. Specific technical objectives are established for each research project. We aim to produce relevant data and basic understanding of material behavior and microstructure, new monolithic and composite alloys, advanced processing methods, new solid and fluid mechanics analyses, measurement advances, and critically, a pool of educated graduate students for aerospace technologies. Four research areas are being actively investigated, including: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals and Composites; (2) Aerospace Materials Science; (3) Mechanics of Materials and Composites for Aerospace Structures; and (4) Thermal Gradient Structures.

  15. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Scully, John R.; Shiflet, Gary J.; Stoner, Glenn E.; Wert, John A.

    1996-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986 and continues with a high level of activity. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies. Three research areas are being actively investigated, including: (1) Mechanical and environmental degradation mechanisms in advanced light metals, (2) Aerospace materials science, and (3) Mechanics of materials for light aerospace structures.

  16. Energy Harvesting for Aerospace Structural Health Monitoring Systems

    NASA Astrophysics Data System (ADS)

    Pearson, M. R.; Eaton, M. J.; Pullin, R.; Featherston, C. A.; Holford, K. M.

    2012-08-01

    Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.

  17. Advanced fusion welding processes, solid state joining and a successful marriage. [production of aerospace structures

    NASA Technical Reports Server (NTRS)

    Miller, F. R.

    1972-01-01

    Joining processes for aerospace systems combine fusion welding and solid state joining during production of metal structures. Detailed characteristics of electron beam welding, plasma arc welding, diffusion welding, inertia welding and weldbond processes are discussed.

  18. IPAD applications to the design, analysis, and/or machining of aerospace structures. [Integrated Program for Aerospace-vehicle Design

    NASA Technical Reports Server (NTRS)

    Blackburn, C. L.; Dovi, A. R.; Kurtze, W. L.; Storaasli, O. O.

    1981-01-01

    A computer software system for the processing and integration of engineering data and programs, called IPAD (Integrated Programs for Aerospace-Vehicle Design), is described. The ability of the system to relieve the engineer of the mundane task of input data preparation is demonstrated by the application of a prototype system to the design, analysis, and/or machining of three simple structures. Future work to further enhance the system's automated data handling and ability to handle larger and more varied design problems are also presented.

  19. Multilevel optimisation of aerospace and lightweight structures incorporating postbuckling effects

    NASA Astrophysics Data System (ADS)

    Qu, Shuang

    The optimisation of aerospace structures is a very complex problem, due to the hundreds of design variables a multidisciplinary optimisation may contain, so that multilevel optimisation is required. This thesis presents the recent developments to the multilevel optimisation software VICONOPT MLO, which is a multilevel optimisation interface between the well established analysis and design software packages VICONOPT and MSC/NASTRAN. The software developed is called VICONOPT MLOP (Multilevel Optimisation with Postbuckling), and allows for postbuckling behaviour, using analysis based on the Wittrick-Williams algorithm. The objective of this research is to enable a more detailed insight into the multilevel optimisation and postbuckling behaviour of a complex structure. In VICONOPT MLOP optimisation problems, individual panels of the structural model are allowed to buckle before the design load is reached. These panels continue to carry load with differing levels of reduced stiffness. VICONOPT MLOP creates new MSC/NASTRAN data files based on this reduced stiffness data and iterates through analysis cycles to converge on an appropriate load re-distribution. Once load convergence has been obtained with an appropriate criterion, the converged load distribution is used as a starting point in the optimisation of the constituent panels, i.e. a new design cycle is started, in which the updated ply thicknesses for each panel are calculated by VICONOPT and returned to MSC/NASTRAN through VICONOPT MLOP. Further finite element analysis of the whole structure is then carried out to determine the new stress distributions in each panel. The whole process is repeated until a mass convergence criterion is met. A detailed overview of the functionality of VICONOPT MLOP is presented in the thesis. A case study is conducted into the multilevel optimisation of a composite aircraft wing, to demonstrate the capabilities of VICONOPT MLOP and identify areas for future studies. The results of

  20. NASA-UVA light aerospace alloy and structures technology program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Starke, Edger A., Jr.

    1996-01-01

    This progress report covers achievements made between January 1 and June 30, 1966 on the NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. . The accomplishments presented in this report are: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals, (2) Aerospace Materials Science, and (3) Mechanics of Materials for Light Aerospace Structures. Collective accomplishments between January and June of 1996 include: 4 journal or proceedings publications, 1 NASA progress report, 4 presentations at national technical meetings, and 2 PhD dissertations published.

  1. NASA-UVA light aerospace alloy and structures technology program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.

    1992-01-01

    The NASA-UVa Light Aerospace Alloy and Structure Technology (LAST) Program continues to maintain a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, Civil Engineering and Applied Mechanics, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, we report on progress achieved between January 1 and June 30, 1992. The objectives of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of the next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with Langley researchers. Technical objectives are established for each research project. We aim to produce relevant data and basic understanding of material mechanical response, corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement advances; and critically, a pool of educated graduate students for aerospace technologies. The accomplishments presented in this report cover topics including: (1) Mechanical and Environmental Degradation Mechanisms in Advance Light Metals and Composites; (2) Aerospace Materials Science; (3) Mechanics of Materials and Composites for Aerospace Structures; and (4) Thermal Gradient Structures.

  2. Structural reliability analysis of laminated CMC components

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.; Palko, Joseph L.; Gyekenyesi, John P.

    1991-01-01

    For laminated ceramic matrix composite (CMC) materials to realize their full potential in aerospace applications, design methods and protocols are a necessity. The time independent failure response of these materials is focussed on and a reliability analysis is presented associated with the initiation of matrix cracking. A public domain computer algorithm is highlighted that was coupled with the laminate analysis of a finite element code and which serves as a design aid to analyze structural components made from laminated CMC materials. Issues relevant to the effect of the size of the component are discussed, and a parameter estimation procedure is presented. The estimation procedure allows three parameters to be calculated from a failure population that has an underlying Weibull distribution.

  3. Dynamic fiber Bragg gratings based health monitoring system of composite aerospace structures

    NASA Astrophysics Data System (ADS)

    Panopoulou, A.; Loutas, T.; Roulias, D.; Fransen, S.; Kostopoulos, V.

    2011-09-01

    The main purpose of the current work is to develop a new system for structural health monitoring of composite aerospace structures based on real-time dynamic measurements, in order to identify the structural state condition. Long-gauge Fibre Bragg Grating (FBG) optical sensors were used for monitoring the dynamic response of the composite structure. The algorithm that was developed for structural damage detection utilizes the collected dynamic response data, analyzes them in various ways and through an artificial neural network identifies the damage state and its location. Damage was simulated by slightly varying locally the mass of the structure (by adding a known mass) at different zones of the structure. Lumped masses in different locations upon the structure alter the eigen-frequencies in a way similar to actual damage. The structural dynamic behaviour has been numerically simulated and experimentally verified by means of modal testing on two different composite aerospace structures. Advanced digital signal processing techniques, e.g. the wavelet transform (WT), were used for the analysis of the dynamic response for feature extraction. WT's capability of separating the different frequency components in the time domain without loosing frequency information makes it a versatile tool for demanding signal processing applications. The use of WT is also suggested by the no-stationary nature of dynamic response signals and the opportunity of evaluating the temporal evolution of their frequency contents. Feature extraction is the first step of the procedure. The extracted features are effective indices of damage size and location. The classification step comprises of a feed-forward back propagation network, whose output determines the simulated damage location. Finally, dedicated training and validation activities were carried out by means of numerical simulations and experimental procedures. Experimental validation was performed initially on a flat stiffened panel

  4. Uncertainty Quantification in Remaining Useful Life of Aerospace Components using State Space Models and Inverse FORM

    NASA Technical Reports Server (NTRS)

    Sankararaman, Shankar; Goebel, Kai

    2013-01-01

    This paper investigates the use of the inverse first-order reliability method (inverse- FORM) to quantify the uncertainty in the remaining useful life (RUL) of aerospace components. The prediction of remaining useful life is an integral part of system health prognosis, and directly helps in online health monitoring and decision-making. However, the prediction of remaining useful life is affected by several sources of uncertainty, and therefore it is necessary to quantify the uncertainty in the remaining useful life prediction. While system parameter uncertainty and physical variability can be easily included in inverse-FORM, this paper extends the methodology to include: (1) future loading uncertainty, (2) process noise; and (3) uncertainty in the state estimate. The inverse-FORM method has been used in this paper to (1) quickly obtain probability bounds on the remaining useful life prediction; and (2) calculate the entire probability distribution of remaining useful life prediction, and the results are verified against Monte Carlo sampling. The proposed methodology is illustrated using a numerical example.

  5. Validating finite element models of composite aerospace structures for damage detection applications

    NASA Astrophysics Data System (ADS)

    Oliver, J. A.; Kosmatka, J. B.; Hemez, François M.; Farrar, Charles R.

    2006-03-01

    Carbon-fiber-reinforced-polymer (CFRP) composites represent the future for advanced lightweight aerospace structures. However, reliable and cost-effective techniques for structural health monitoring (SHM) are needed. Modal and vibration-based analysis, when combined with validated finite element (FE) models, can provide a key tool for SHM. Finite element models, however, can easily give spurious and misleading results if not finely tuned and validated. These problems are amplified in complex structures with numerous joints and interfaces. A small series of all-composite test pieces emulating wings from a lightweight all-composite Unmanned Aerial Vehicle (UAV) have been developed to support damage detection and SHM research. Each wing comprises two CFRP prepreg and Nomex honeycomb co-cured skins and two CFRP prepreg spars bonded together in a secondary process using a structural adhesive to form the complete wings. The first of the set is fully healthy while the rest have damage in the form of disbonds built into the main spar-skin bondline. Detailed FE models were created of the four structural components and the assembled structure. Each wing component piece was subjected to modal characterization via vibration testing using a shaker and scanning laser Doppler vibrometer before assembly. These results were then used to correlate the FE model on a component-basis, through fitting and optimization of polynomial meta-models. Assembling and testing the full wing provided subsequent data that was used to validate the numerical model of the entire structure, assembled from the correlated component models. The correlation process led to the following average percent improvement between experimental and FE frequencies of the first 20 modes for each piece: top skin 10.98%, bottom skin 45.62%, main spar 25.56%, aft spar 10.79%. The assembled wing model with no further correlation showed an improvement of 32.60%.

  6. Structural health monitoring of aerospace materials used in industry using electrical potential mapping methods

    NASA Astrophysics Data System (ADS)

    Grammatikos, S. A.; Kouli, M.-E.; Gkikas, G.; Paipetis, A. S.

    2012-04-01

    The increasing use of composite materials in aerostructures has prompted the development of an effective structural health monitoring system. A safe and economical way of inspection is needed in order for composite materials to be used more extensively. Critical defects may be induced during the scheduled repair which may degrade severely the mechanical properties of the structure. Low velocity impact LVI damage is one of the most dangerous and very difficult to detect types of structural deterioration as delaminations and flaws are generated and propagated during the life of the structure. In that sense large areas need to be scanned rapidly and efficiently without removal of the particular components. For that purpose, an electrical potential mapping was employed for the identification of damage and the structural degradation of aerospace materials. Electric current was internally injected and the potential difference was measured in order to identify induced damage in Carbon Fiber Reinforced Polymer (CFRP) structures. The experimental results of the method were compared with conventional C-scan imaging and evaluated.

  7. The role of polymer based composites materials in modern and future aerospace structures

    NASA Astrophysics Data System (ADS)

    Cantoni, Stefania; De Nicola, Felice; Mercurio, Umberto; Quaranta, Vincenzo

    2014-05-01

    The need to reduce the overall weight of aeronautical and space structures, while at the same time preserving or even improving their performances, make the research and development in the field of innovative structures and advanced composite materials a crucial step for the advancement of aerospace technologies. Several fields of innovation have been explored in the last decades but the most promising solutions for the future of aerospace structures will be found in the "intelligent" use of polymer based composite materials both in the design and in their "nature like" use.

  8. Manufacturing and NDE of Large Composite Aerospace Structures at MSFC

    NASA Technical Reports Server (NTRS)

    Whitaker, Ann

    2000-01-01

    NASA's vision for transportation to orbit calls for new vehicles built with new materials technology. The goals of this new launch system development are to improve safety, dramatically reduce cost to orbit, and improve vehicle turn around time. Planned Space Shuttle upgrades include new reusable liquid propellant boosters to replace the solid propellant boosters. These boosters are to have wings and return to the launch site for a horizontal landing on an airport runway. New single and two stages to orbit concepts are being investigated. To reduce weight and improve performance composite materials are proposed for fuel and oxidizer tanks, fuel feedlines, valve bodies, aerostructures, turbomachinery components. For large composite structures new methods of fabrication are being proposed and developed. Containment of cryogenic fuel or oxidizer requires emphases on composite material densification and chemical compatibility. Ceramic matrix and fiber composites for hot rotating turbomachinery have been developed with new fabrication processes. The new requirements on the materials for launcher components are requiring development of new manufacturing and inspection methods. This talk will examine new and proposed manufacturing methods to fabricate the revolutionary components. New NDE methods under consideration include alternative X-ray methods, X-ray laminagraphy, advanced CT, Thermography, new ultrasonic methods, and imbedded sensors. The sizes, complexity, use environment, and contamination restrictions will challenge the inspection process. In flight self-diagnosis and rapid depot inspection are also goals of the NDE development.

  9. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Starke, Edgar A., Jr.; Kelly, Robert G.; Scully, John R.; Shiflet, Gary J.; Stoner, Glenn E.; Wert, John A.

    1997-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986 and continues with a high level of activity. Here, we report on progress achieved between July I and December 31, 1996. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies. The accomplishments presented in this report are summarized as follows. Three research areas are being actively investigated, including: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals, (2) Aerospace Materials Science, and (3) Mechanics of Materials for Light Aerospace Structures.

  10. Photogrammetric Verification of Fiber Optic Shape Sensors on Flexible Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Moore, Jason P.; Rogge, Matthew D.; Jones, Thomas W.

    2012-01-01

    Multi-core fiber (MCF) optic shape sensing offers the possibility of providing in-flight shape measurements of highly flexible aerospace structures and control surfaces for such purposes as gust load alleviation, flutter suppression, general flight control and structural health monitoring. Photogrammetric measurements of surface mounted MCF shape sensing cable can be used to quantify the MCF installation path and verify measurement methods.

  11. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.

    1991-01-01

    The general objective of the Light Aerospace Alloy and Structures Technology (LA2ST) Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures in close collaboration with Langley researchers. Specific technical objectives are established for each research project. Relevant data and basic understanding of material behavior and microstructure, new monolithic and composite alloys, advanced processing methods, new solid and fluid mechanic analyses, measurement advances, and a pool of educated graduate students are sought.

  12. High temperature resin matrix composites for aerospace structures

    NASA Technical Reports Server (NTRS)

    Davis, J. G., Jr.

    1980-01-01

    Accomplishments and the outlook for graphite-polyimide composite structures are briefly outlined. Laminates, skin-stiffened and honeycomb sandwich panels, chopped fiber moldings, and structural components were fabricated with Celion/LARC-160 and Celion/PMR-15 composite materials. Interlaminar shear and flexure strength data obtained on as-fabricated specimens and specimens that were exposed for 125 hours at 589 K indicate that epoxy sized and polyimide sized Celion graphite fibers exhibit essentially the same behavior in a PMR-15 matrix composite. Analyses and tests of graphite-polyimide compression and shear panels indicate that utilization in moderately loaded applications offers the potential for achieving a 30 to 50 percent reduction in structural mass compared to conventional aluminum panels. Data on effects of moisture, temperature, thermal cycling, and shuttle fluids on mechanical properties indicate that both LARC-160 and PMR-15 are suitable matrix materials for a graphite-polyimide aft body flap. No technical road blocks to building a graphite-polyimide composite aft body flap are identified.

  13. Optical Fiber Strain Instrumentation for High Temperature Aerospace Structural Monitoring

    NASA Technical Reports Server (NTRS)

    Wang, A.

    2002-01-01

    The objective of the program is the development and laboratory demonstration of sensors based on silica optical fibers for measurement of high temperature strain for aerospace materials evaluations. A complete fiber strain sensor system based on white-light interferometry was designed and implemented. An experiment set-up was constructed to permit testing of strain measurement up to 850 C. The strain is created by bending an alumina cantilever beam to which is the fiber sensor is attached. The strain calibration is provided by the application of known beam deflections. To ensure the high temperature operation capability of the sensor, gold-coated single-mode fiber is used. Moreover, a new method of sensor surface attachment which permits accurate sensor gage length determination is also developed. Excellent results were obtained at temperatures up to 800-850 C.

  14. The application of thermoelastic stress analysis to full-scale aerospace structures

    NASA Astrophysics Data System (ADS)

    Fruehmann, R. K.; Dulieu-Barton, J. M.; Quinn, S.; Peton-Walter, J.; Mousty, P. A. N.

    2012-08-01

    Non-destructive evaluation (NDE) techniques that can be applied in-situ are particularly relevant to the testing of large scale structures that cannot easily be taken into a laboratory for inspection. The application of established laboratory based techniques to the inspection of such structures therefore brings with it a new set of challenges associated with the change in operating environment between the laboratory and 'the field'. The current work investigates the use of thermoelastic stress analysis (TSA) to inspect carbon fibre composite aerospace components for manufacturing defects and in-service damage. An initial study using single transient loads to obtain a measureable change in temperature that can be related to the change in the sum of the principal stresses showed a good agreement with the traditional methodology. However, for large structures, the energy required to obtain a sufficiently large stress change to obtain a resolvable measurement may require an actuator that is not easily portable. Hence a number of ideas have been proposed to reduce the power requirement and deal with small signal to noise ratios. This paper describes the use of natural frequency vibration modes to enable large stress changes to be generated with minimal power input. Established signal processing in the form of a lock-in amplifier and Fourier signal analysis is applied. Tests on a laboratory scale flat plate and full-scale representative wing skin and stringer specimen are presented.

  15. A Qualitative Program Evaluation of a Structured Leadership Mentoring Program at a Large Aerospace Corporation

    ERIC Educational Resources Information Center

    Teller, Romney P.

    2011-01-01

    The researcher utilized a qualitative approach to conduct a program evaluation of the organization where he is employed. The study intended to serve as a program evaluation for the structured in-house mentoring program at a large aerospace corporation (A-Corp). This program evaluation clarified areas in which the current mentoring program is…

  16. Regularized Generalized Structured Component Analysis

    ERIC Educational Resources Information Center

    Hwang, Heungsun

    2009-01-01

    Generalized structured component analysis (GSCA) has been proposed as a component-based approach to structural equation modeling. In practice, GSCA may suffer from multi-collinearity, i.e., high correlations among exogenous variables. GSCA has yet no remedy for this problem. Thus, a regularized extension of GSCA is proposed that integrates a ridge…

  17. An expert system for integrated structural analysis and design optimization for aerospace structures

    NASA Astrophysics Data System (ADS)

    1992-04-01

    The results of a research study on the development of an expert system for integrated structural analysis and design optimization is presented. An Object Representation Language (ORL) was developed first in conjunction with a rule-based system. This ORL/AI shell was then used to develop expert systems to provide assistance with a variety of structural analysis and design optimization tasks, in conjunction with procedural modules for finite element structural analysis and design optimization. The main goal of the research study was to provide expertise, judgment, and reasoning capabilities in the aerospace structural design process. This will allow engineers performing structural analysis and design, even without extensive experience in the field, to develop error-free, efficient and reliable structural designs very rapidly and cost-effectively. This would not only improve the productivity of design engineers and analysts, but also significantly reduce time to completion of structural design. An extensive literature survey in the field of structural analysis, design optimization, artificial intelligence, and database management systems and their application to the structural design process was first performed. A feasibility study was then performed, and the architecture and the conceptual design for the integrated 'intelligent' structural analysis and design optimization software was then developed. An Object Representation Language (ORL), in conjunction with a rule-based system, was then developed using C++. Such an approach would improve the expressiveness for knowledge representation (especially for structural analysis and design applications), provide ability to build very large and practical expert systems, and provide an efficient way for storing knowledge. Functional specifications for the expert systems were then developed. The ORL/AI shell was then used to develop a variety of modules of expert systems for a variety of modeling, finite element analysis, and

  18. An expert system for integrated structural analysis and design optimization for aerospace structures

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The results of a research study on the development of an expert system for integrated structural analysis and design optimization is presented. An Object Representation Language (ORL) was developed first in conjunction with a rule-based system. This ORL/AI shell was then used to develop expert systems to provide assistance with a variety of structural analysis and design optimization tasks, in conjunction with procedural modules for finite element structural analysis and design optimization. The main goal of the research study was to provide expertise, judgment, and reasoning capabilities in the aerospace structural design process. This will allow engineers performing structural analysis and design, even without extensive experience in the field, to develop error-free, efficient and reliable structural designs very rapidly and cost-effectively. This would not only improve the productivity of design engineers and analysts, but also significantly reduce time to completion of structural design. An extensive literature survey in the field of structural analysis, design optimization, artificial intelligence, and database management systems and their application to the structural design process was first performed. A feasibility study was then performed, and the architecture and the conceptual design for the integrated 'intelligent' structural analysis and design optimization software was then developed. An Object Representation Language (ORL), in conjunction with a rule-based system, was then developed using C++. Such an approach would improve the expressiveness for knowledge representation (especially for structural analysis and design applications), provide ability to build very large and practical expert systems, and provide an efficient way for storing knowledge. Functional specifications for the expert systems were then developed. The ORL/AI shell was then used to develop a variety of modules of expert systems for a variety of modeling, finite element analysis, and

  19. Comparison and analysis of two modern methods in the structural health monitoring techniques in aerospace

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammad; Ahmadi, Alireza

    2016-04-01

    Role of air transport in the development and expansion of world trade leading to economic growth of different countries is undeniable. Continuing the world's trade sustainability without expansion of aerospace is next to impossible. Based on enormous expenses for design, manufacturing and maintenance of different aerospace structures, correct and timely diagnosis of defects in those structures to provide for maximum safety has the highest importance. Amid all this, manufacturers of commercial and even military aircrafts are after production of less expensive, lighter, higher fuel economy and nonetheless, higher safety. As such, two events has prevailed in the aerospace industries: (1) Utilization of composites for the fuselage as well as other airplane parts, (2) using modern manufacturing methods. Arrival of two these points have created the need for upgrading of the present systems as well as innovating newer methods in diagnosing and detection of defects in aerospace structures. Despite applicability of nondestructive testing (NDT) methods in aerospace for decades, due to some limitations in the defect detection's certainty, particularly for composite material and complex geometries, shadow of doubt has fallen on maintaining complete confidence in using NDT. These days, two principal approach are ahead to tackle the above mentioned problems. First, approach for the short range is the creative and combinational mean to increase the reliability of NDT and for the long run, innovation of new methods on the basis of structural health monitoring (SHM) is in order. This has led to new philosophy in the maintenance area and in some instances; field of design has also been affected by it.

  20. Micromechanical Machining Processes and their Application to Aerospace Structures, Devices and Systems

    NASA Technical Reports Server (NTRS)

    Friedrich, Craig R.; Warrington, Robert O.

    1995-01-01

    Micromechanical machining processes are those micro fabrication techniques which directly remove work piece material by either a physical cutting tool or an energy process. These processes are direct and therefore they can help reduce the cost and time for prototype development of micro mechanical components and systems. This is especially true for aerospace applications where size and weight are critical, and reliability and the operating environment are an integral part of the design and development process. The micromechanical machining processes are rapidly being recognized as a complementary set of tools to traditional lithographic processes (such as LIGA) for the fabrication of micromechanical components. Worldwide efforts in the U.S., Germany, and Japan are leading to results which sometimes rival lithography at a fraction of the time and cost. Efforts to develop processes and systems specific to aerospace applications are well underway.

  1. NASA-UVA Light Aerospace Alloy and Structures Technology Program: LA(2)ST

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Haviland, John K.; Herakovich, Carl T.; Pilkey, Walter D.; Pindera, Marek-Jerzy; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1993-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA(2)ST) Program continues a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, Civil Engineering and Applied Mechanics, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. We report on progress achieved between July 1 and December 31, 1992. The objective of the LA(2)ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement advances; and critically, a pool of educated graduate students for aerospace technologies.

  2. NASA-UVA light aerospace alloy and structures technology program (LA2ST)

    NASA Astrophysics Data System (ADS)

    Gangloff, Richard P.; Scully, John R.; Starke, Edgar A., Jr.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1994-03-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986, and continues a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, we report on progress achieved between July 1 and December 31, 1993. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and critically, a pool of educated graduate students for aerospace technologies.

  3. NASA-UVA light aerospace alloy and structures technology program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Scully, John R.; Starke, Edgar A., Jr.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1994-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986, and continues a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, we report on progress achieved between July 1 and December 31, 1993. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and critically, a pool of educated graduate students for aerospace technologies.

  4. Surface generation and editing operations applied to structural support of aerospace vehicle fuselages. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Schwartz, Susan K.

    1992-01-01

    The Solid Modeling Aerospace Research Tool (SMART) is a computer aided design tool used in aerospace vehicle design. Modeling of structural components using SMART includes the representation of the transverse or cross-wise elements of a vehicle's fuselage, ringframes, and bulkheads. Ringframes are placed along a vehicle's fuselage to provide structural support and maintain the shape of the fuselage. Bulkheads are also used to maintain shape, but are placed at locations where substantial structural support is required. Given a Bezier curve representation of a cross sectional cut through a vehicle's fuselage and/or an internal tank, this project produces a first-guess Bezier patch representation of a ringframe or bulkhead at the cross-sectional position. The grid produced is later used in the structural analysis of the vehicle. The graphical display of the generated patches allows the user to edit patch control points in real time. Constraints considered in the patch generation include maintaining 'square-like' patches and placement of longitudinal, or lengthwise along the fuselage, structural elements called longerons.

  5. Computerized structural sizing at NASA Langley Research Center. [low mass design for aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Stroud, W. J.; Sobieszczanski-Sobieski, J.; Walz, J. E.; Bush, H. G.

    1978-01-01

    Programs at the NASA Langley Research Center associated with the development of computerized structural sizing technology are reviewed. Particular attention is given to (1) lightweight columns for space structure applications, (2) stiffened composite panels for aerospace structures, (3) thermal structures for high-speed aircraft and space vehicles, (4) structural sizing methodology for finite-element structural models, (5) the sizing of large complex structural systems in multidisciplinary environments. Improvements to computational efficiency are noted with reference to a reduced number of sizing variables, a reduced number of constraints, and improved sizing algorithms.

  6. Combined electromechanical impedance and fiber optic diagnosis of aerospace structures

    NASA Astrophysics Data System (ADS)

    Schlavin, Jon; Zagrai, Andrei; Clemens, Rebecca; Black, Richard J.; Costa, Joey; Moslehi, Behzad; Patel, Ronak; Sotoudeh, Vahid; Faridian, Fereydoun

    2014-03-01

    Electromechanical impedance is a popular diagnostic method for assessing structural conditions at high frequencies. It has been utilized, and shown utility, in aeronautic, space, naval, civil, mechanical, and other types of structures. By contrast, fiber optic sensing initially found its niche in static strain measurement and low frequency structural dynamic testing. Any low frequency limitations of the fiber optic sensing, however, are mainly governed by its hardware elements. As hardware improves, so does the bandwidth (frequency range * number of sensors) provided by the appropriate enabling fiber optic sensor interrogation system. In this contribution we demonstrate simultaneous high frequency measurements using fiber optic and electromechanical impedance structural health monitoring technologies. A laboratory specimen imitating an aircraft wing structure, incorporating surfaces with adjustable boundary conditions, was instrumented with piezoelectric and fiber optic sensors. Experiments were conducted at different structural boundary conditions associated with deterioration of structural health. High frequency dynamic responses were collected at multiple locations on a laboratory wing specimen and conclusions were drawn about correspondence between structural damage and dynamic signatures as well as correlation between electromechanical impedance and fiber optic sensors spectra. Theoretical investigation of the effect of boundary conditions on electromechanical impedance spectra is presented and connection to low frequency structural dynamics is suggested. It is envisioned that acquisition of high frequency structural dynamic responses with multiple fiber optic sensors may open new diagnostic capabilities for fiber optic sensing technologies.

  7. Sensor applications for structural diagnostics and prognostics in aerospace systems

    NASA Astrophysics Data System (ADS)

    Ghoshal, Anindya; Ayers, James T.; Haile, Mulugeta; Shiao, Michael; Le, Dy D.

    2012-04-01

    There are emerging sensor technologies that will be deployed in future rotorcraft or retrofitted to existing rotorcraft and aircraft for structural diagnostics and prognostics. The vehicle health management system is likely to contain heterogeneous sensor arrays. Thus the structural state awareness may require information data fusion from dissimilar sensor (heterogeneous) system. This paper reviews the state of the art commercial of the shelf (COTS) and emerging sensor technologies for structural damage monitoring of rotorcraft and aircraft health.

  8. Integrated Component-based Data Acquisition Systems for Aerospace Test Facilities

    NASA Technical Reports Server (NTRS)

    Ross, Richard W.

    2001-01-01

    The Multi-Instrument Integrated Data Acquisition System (MIIDAS), developed by the NASA Langley Research Center, uses commercial off the shelf (COTS) products, integrated with custom software, to provide a broad range of capabilities at a low cost throughout the system s entire life cycle. MIIDAS combines data acquisition capabilities with online and post-test data reduction computations. COTS products lower purchase and maintenance costs by reducing the level of effort required to meet system requirements. Object-oriented methods are used to enhance modularity, encourage reusability, and to promote adaptability, reducing software development costs. Using only COTS products and custom software supported on multiple platforms reduces the cost of porting the system to other platforms. The post-test data reduction capabilities of MIIDAS have been installed at four aerospace testing facilities at NASA Langley Research Center. The systems installed at these facilities provide a common user interface, reducing the training time required for personnel that work across multiple facilities. The techniques employed by MIIDAS enable NASA to build a system with a lower initial purchase price and reduced sustaining maintenance costs. With MIIDAS, NASA has built a highly flexible next generation data acquisition and reduction system for aerospace test facilities that meets customer expectations.

  9. Fiber Optic Thermal Health Monitoring of Aerospace Structures and Materials

    NASA Technical Reports Server (NTRS)

    Wu, Meng-Chou; Winfree, William P.; Allison, Sidney G.

    2009-01-01

    A new technique is presented for thermographic detection of flaws in materials and structures by performing temperature measurements with fiber Bragg gratings. Individual optical fibers with multiple Bragg gratings employed as surface temperature sensors were bonded to the surfaces of structures with subsurface defects or thickness variations. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The investigated structures included a 10-ply composite specimen with subsurface delaminations of various sizes and depths. The data obtained from grating sensors were further analyzed with thermal modeling to reveal particular characteristics of the interested areas. These results were found to be consistent with those from conventional thermography techniques. Limitations of the technique were investigated using both experimental and numerical simulation techniques. Methods for performing in-situ structural health monitoring are discussed.

  10. Spectroscopic detection and analysis of atomic emissions during industrial pulsed laser-drilling of structural aerospace alloys

    NASA Astrophysics Data System (ADS)

    Bright, Robin Michael

    The ability to adequately cool internal gas-turbine engine components in next-generation commercial and military aircraft is of extreme importance to the aerospace industry as the demand for high-efficiency engines continues to push operating temperatures higher. Pulsed laser-drilling is rapidly becoming the preferred method of creating cooling holes in high temperature components due a variety of manufacturing advantages of laser-drilling over conventional hole-drilling techniques. As cooling requirements become more demanding, the impact of drilling conditions on material removal behavior and subsequent effects on hole quality becomes critical. In this work, the development of emission spectroscopy as a method to probe the laser-drilling process is presented and subsequently applied to the study of material behavior of various structural aerospace materials during drilling. Specifically, emitted photons associated with energy level transitions within excited neutral atoms in material ejected during drilling were detected and analyzed. Systematic spectroscopic studies indicated that electron energy level populations and calculated electron temperatures within ejected material are dependent on both laser pulse energy and duration. Local thermal conditions detected by the developed method were related to the characteristics of ejected material during drilling and to final hole quality. Finally, methods of utilizing the observed relationships for spectroscopic process monitoring and control were demonstrated.

  11. 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.

  12. Structural health monitoring of aerospace applications with restricted geometry

    NASA Astrophysics Data System (ADS)

    Underwood, Roman T.; Swenson, Eric D.; Soni, Som R.

    2008-03-01

    This paper presents a set of results from an experiment that is designed to evaluate a damage detection approach for through-thickness fatigue cracks emanating from a rivet hole in a high-performance aircraft bulkhead. Because fatigue cracks have been found through depot-level visual-inspections at the same location in several aircraft bulkheads, a "hot-spot" approach to monitor this area with Lamb waves generated from surface-mounted lead ziconate titanate (PZT) transducers is evaluated. Detecting these fatigue cracks is challenging because the cracks propagate through an area of restricted geometry - a small plate-like area surrounded by thick webbing - which results in the interference of reflected wave components with the direct path wave components when using a pitch-catch approach. To minimize this interference, time-of-flight windows are applied to remove the reflected signals, and to increase probability of detection, Lamb wave mode tuning is used. Finally, to make the crack easier to detect, various static loads are applied to open the crack, but new challenges are presented when attempting to detect damage under a static load.

  13. Rapid Inspection of Aerospace Structures - Is It Autonomous Yet?

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Backes, Paul; Joffe, Benjamin

    1996-01-01

    The trend to increase the usage of aging aircraft added a great deal of urgency to the ongoing need for low-cost, rapid, simple-to-operate, reliable and efficient NDE methods for detection and characterization of flaws in aircraft structures. In many cases, the problem of inspection is complex due to the limitation of current technology and the need to disassemble aircraft structures and testing them in lab conditions. To overcome these limitations, reliable field inspection tools are being developed for rapid NDE of large and complex-shape structures, that can operate at harsh, hostal and remote conditions with minimum human interface. In recent years, to address the need for rapid inspection in field conditions, numerous portable scanners were developed using NDE methods, including ultrasonics, shearography, thermography. This paper is written with emphasis on ultrasonic NDE scanners, their evolution and the expected direction of growth.

  14. Parametric Studies for the Structural Pre-Design of Hypersonic Aerospace Vehicles

    NASA Astrophysics Data System (ADS)

    Kopp, Alexander

    2012-07-01

    The Space Launcher Systems Analysis Group (SART) of the German Aerospace Center DLR is involved in various internal and multilateral hypersonic vehicle studies. Hypersonic transportation vehicles require structural analysis already in an early design phase to enable accurate structural mass estimations. A program for preliminary structural analysis of hypersonic transportation vehicles will be presented here. The program HySAP serves for rapid, parametric trade studies. The requirements will be derived and the program structure described in detail. Furthermore, first application cases for the program version will be discussed.

  15. Qualifying of metallic materials and structures for aerospace applications

    NASA Astrophysics Data System (ADS)

    Frazier, William E.; Polakovics, Donald; Koegel, Wayne

    2001-03-01

    The U.S. Navy’s certification and qualification process for materials and structures is undertaken to ensure the flight safety and full mission capability of naval aviation weapon systems. A building-block process is practiced in which validated engineering data and concepts provide the foundation for continued technological development and innovation. For example, prior to developing material-property standards, the manufacturing process is frozen and fully characterized. The customer’s cost, schedule, and performance requirements must be carefully considered. Technologies are selected for immediate use or further R&D based upon a risk assessment that takes into account many factors, including technological maturity, lessons learned, the sponsor budget and schedule constraints, affordability, return on investment, and life-cycle cost impact. This paper explores the process that the navy uses to qualify its airframe alloys and structures.

  16. Laser Surface Preparation and Bonding of Aerospace Structural Composites

    NASA Technical Reports Server (NTRS)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.

    2010-01-01

    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical prebonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  17. Cyber Technology for Materials and Structures in Aeronautics and Aerospace

    NASA Technical Reports Server (NTRS)

    Pipes, R. Byron

    1999-01-01

    This report summarizes efforts undertaken during the 1998-99 program year and includes a survey of the field of computational mechanics, a discussion of biomimetics and intelligent simulation, a survey of the field of biomimetics, an illustration of biomimetics and computational mechanics through the example of the high performance composite tensile structure. In addition, the preliminary results of a state-of-the art survey of composite materials technology is presented.

  18. Interdisciplinary and multilevel optimum design. [in aerospace structural engineering

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

    1987-01-01

    Interactions among engineering disciplines and subsystems in engineering system design are surveyed and specific instances of such interactions are described. Examination of the interactions that a traditional design process in which the numerical values of major design variables are decided consecutively is likely to lead to a suboptimal design. Supporting numerical examples are a glider and a space antenna. Under an alternative approach introduced, the design and its sensitivity data from the subsystems and disciplines are generated concurrently and then made available to the system designer enabling him to modify the system design so as to improve its performance. Examples of a framework structure and an airliner wing illustrate that approach.

  19. Structural Efficiency of Composite Struts for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.; Wu, K. Chauncey; McKenney, Martin J.; Oremont, Leonard

    2011-01-01

    The structural efficiency of carbon-epoxy tapered struts is considered through trade studies, detailed analysis, manufacturing and experimentation. Since some of the lunar lander struts are more highly loaded than struts used in applications such as satellites and telescopes, the primary focus of the effort is on these highly loaded struts. Lunar lander requirements include that the strut has to be tapered on both ends, complicating the design and limiting the manufacturing process. Optimal stacking sequences, geometries, and materials are determined and the sensitivity of the strut weight to each parameter is evaluated. The trade study results indicate that the most efficient carbon-epoxy struts are 30 percent lighter than the most efficient aluminum-lithium struts. Structurally efficient, highly loaded struts were fabricated and loaded in tension and compression to determine if they met the design requirements and to verify the accuracy of the analyses. Experimental evaluation of some of these struts demonstrated that they could meet the greatest Altair loading requirements in both tension and compression. These results could be applied to other vehicles requiring struts with high loading and light weight.

  20. Laser Surface Preparation for Adhesive Bonding of Aerospace Structural Composites

    NASA Technical Reports Server (NTRS)

    Belcher, M. A.; Wohl, C. J.; Hopkins, J. W.; Connell, J. W.

    2010-01-01

    Adhesive bonds are critical to the integrity of built-up structures. Disbonds can often be detected but the strength of adhesion between surfaces in contact is not obtainable without destructive testing. Typically the number one problem in a bonded structure is surface contamination, and by extension, surface preparation. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, are not ideal because of variations in their application. Etching of carbon fiber reinforced plastic (CFRP) panels using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser appears to be a highly precise and promising way to both clean a composite surface prior to bonding and provide a bond-promoting patterned surface akin to peel ply without the inherent drawbacks from the same (i.e., debris and curvature). CFRP surfaces prepared using laser patterns conducive to adhesive bonding were compared to typical pre-bonding surface treatments through optical microscopy, contact angle goniometry, and post-bonding mechanical testing.

  1. NASA-UVA light aerospace alloy and structures technology program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Starke, Edgar A., Jr.; Gangloff, Richard P.; Herakovich, Carl T.; Scully, John R.; Shiflet, Gary J.; Stoner, Glenn E.; Wert, John A.

    1995-01-01

    The NASA-UVa Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986 and continues with a high level of activity. Projects are being conducted by graduate students and faculty advisors in the Department of Materials Science and Engineering, as well as in the Department of Civil Engineering and Applied Mechanics, at the University of Virginia. Here, we report on progress achieved between July 1 and December 31, 1994. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies.

  2. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.

    1994-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986 and continues with a high level of activity. Projects are being conducted by graduate students and faculty advisors in the Department of Materials Science and Engineering, as well as in the Department of Civil Engineering and Applied Mechanics, at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, we report on progress achieved between January 1 and June 30, 1994. These results were presented at the Fifth Annual NASA LA2ST Grant Review Meeting held at the Langley Research Center in July of 1994. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, lightweight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. We generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies.

  3. A generalized concept for cost-effective structural design. [Statistical Decision Theory applied to aerospace systems

    NASA Technical Reports Server (NTRS)

    Thomas, J. M.; Hawk, J. D.

    1975-01-01

    A generalized concept for cost-effective structural design is introduced. It is assumed that decisions affecting the cost effectiveness of aerospace structures fall into three basic categories: design, verification, and operation. Within these basic categories, certain decisions concerning items such as design configuration, safety factors, testing methods, and operational constraints are to be made. All or some of the variables affecting these decisions may be treated probabilistically. Bayesian statistical decision theory is used as the tool for determining the cost optimum decisions. A special case of the general problem is derived herein, and some very useful parametric curves are developed and applied to several sample structures.

  4. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors.

    PubMed

    Si, Liang; Baier, Horst

    2015-01-01

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with "orange peel" surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments. PMID:26184196

  5. Real-Time Impact Visualization Inspection of Aerospace Composite Structures with Distributed Sensors

    PubMed Central

    Si, Liang; Baier, Horst

    2015-01-01

    For the future design of smart aerospace structures, the development and application of a reliable, real-time and automatic monitoring and diagnostic technique is essential. Thus, with distributed sensor networks, a real-time automatic structural health monitoring (SHM) technique is designed and investigated to monitor and predict the locations and force magnitudes of unforeseen foreign impacts on composite structures and to estimate in real time mode the structural state when impacts occur. The proposed smart impact visualization inspection (IVI) technique mainly consists of five functional modules, which are the signal data preprocessing (SDP), the forward model generator (FMG), the impact positioning calculator (IPC), the inverse model operator (IMO) and structural state estimator (SSE). With regard to the verification of the practicality of the proposed IVI technique, various structure configurations are considered, which are a normal CFRP panel and another CFRP panel with “orange peel” surfaces and a cutout hole. Additionally, since robustness against several background disturbances is also an essential criterion for practical engineering demands, investigations and experimental tests are carried out under random vibration interfering noise (RVIN) conditions. The accuracy of the predictions for unknown impact events on composite structures using the IVI technique is validated under various structure configurations and under changing environmental conditions. The evaluated errors all fall well within a satisfactory limit range. Furthermore, it is concluded that the IVI technique is applicable for impact monitoring, diagnosis and assessment of aerospace composite structures in complex practical engineering environments. PMID:26184196

  6. Friction Stir Welding of Metal Matrix Composites for use in aerospace structures

    NASA Astrophysics Data System (ADS)

    Prater, Tracie

    2014-01-01

    Friction Stir Welding (FSW) is a relatively nascent solid state joining technique developed at The Welding Institute (TWI) in 1991. The process was first used at NASA to weld the super lightweight external tank for the Space Shuttle. Today FSW is used to join structural components of the Delta IV, Atlas V, and Falcon IX rockets as well as the Orion Crew Exploration Vehicle. A current focus of FSW research is to extend the process to new materials which are difficult to weld using conventional fusion techniques. Metal Matrix Composites (MMCs) consist of a metal alloy reinforced with ceramics and have a very high strength to weight ratio, a property which makes them attractive for use in aerospace and defense applications. MMCs have found use in the space shuttle orbiter's structural tubing, the Hubble Space Telescope's antenna mast, control surfaces and propulsion systems for aircraft, and tank armors. The size of MMC components is severely limited by difficulties encountered in joining these materials using fusion welding. Melting of the material results in formation of an undesirable phase (formed when molten Aluminum reacts with the reinforcement) which leaves a strength depleted region along the joint line. Since FSW occurs below the melting point of the workpiece material, this deleterious phase is absent in FSW-ed MMC joints. FSW of MMCs is, however, plagued by rapid wear of the welding tool, a consequence of the large discrepancy in hardness between the steel tool and the reinforcement material. This work characterizes the effect of process parameters (spindle speed, traverse rate, and length of joint) on the wear process. Based on the results of these experiments, a phenomenological model of the wear process was constructed based on the rotating plug model for FSW. The effectiveness of harder tool materials (such as Tungsten Carbide, high speed steel, and tools with diamond coatings) to combat abrasive wear is explored. In-process force, torque, and

  7. A Conceptual Aerospace Vehicle Structural System Modeling, Analysis and Design Process

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivek

    2007-01-01

    A process for aerospace structural concept analysis and design is presented, with examples of a blended-wing-body fuselage, a multi-bubble fuselage concept, a notional crew exploration vehicle, and a high altitude long endurance aircraft. Aerospace vehicle structures must withstand all anticipated mission loads, yet must be designed to have optimal structural weight with the required safety margins. For a viable systems study of advanced concepts, these conflicting requirements must be imposed and analyzed early in the conceptual design cycle, preferably with a high degree of fidelity. In this design process, integrated multidisciplinary analysis tools are used in a collaborative engineering environment. First, parametric solid and surface models including the internal structural layout are developed for detailed finite element analyses. Multiple design scenarios are generated for analyzing several structural configurations and material alternatives. The structural stress, deflection, strain, and margins of safety distributions are visualized and the design is improved. Over several design cycles, the refined vehicle parts and assembly models are generated. The accumulated design data is used for the structural mass comparison and concept ranking. The present application focus on the blended-wing-body vehicle structure and advanced composite material are also discussed.

  8. Combined Loads Test Fixture for Thermal-Structural Testing Aerospace Vehicle Panel Concepts

    NASA Technical Reports Server (NTRS)

    Fields, Roger A.; Richards, W. Lance; DeAngelis, Michael V.

    2004-01-01

    A structural test requirement of the National Aero-Space Plane (NASP) program has resulted in the design, fabrication, and implementation of a combined loads test fixture. Principal requirements for the fixture are testing a 4- by 4-ft hat-stiffened panel with combined axial (either tension or compression) and shear load at temperatures ranging from room temperature to 915 F, keeping the test panel stresses caused by the mechanical loads uniform, and thermal stresses caused by non-uniform panel temperatures minimized. The panel represents the side fuselage skin of an experimental aerospace vehicle, and was produced for the NASP program. A comprehensive mechanical loads test program using the new test fixture has been conducted on this panel from room temperature to 500 F. Measured data have been compared with finite-element analyses predictions, verifying that uniform load distributions were achieved by the fixture. The overall correlation of test data with analysis is excellent. The panel stress distributions and temperature distributions are very uniform and fulfill program requirements. This report provides details of an analytical and experimental validation of the combined loads test fixture. Because of its simple design, this unique test fixture can accommodate panels from a variety of aerospace vehicle designs.

  9. NASA-UVA Light Aerospace Alloy and Structures Technology program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Starke, Edgar A., Jr.; Gangloff, Richard P.; Herakovich, Carl T.; Scully, John R.; Shiflet, Gary J.; Stoner, Glenn E.; Wert, John A.

    1995-01-01

    The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The general aim is to produce relevant data and basic understanding of material mechanical response, environment/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated students for aerospace technologies. Specific technical objectives are presented for each of the following research projects: time-temperature dependent fracture in advanced wrought ingot metallurgy, and spray deposited aluminum alloys; cryogenic temperature effects on the deformation and fracture of Al-Li-Cu-In alloys; effects of aging and temperature on the ductile fracture of AA2095 and AA2195; mechanisms of localized corrosion in alloys 2090 and 2095; hydrogen interactions in aluminum-lithium alloys 2090 and selected model alloys; mechanisms of deformation and fracture in high strength titanium alloys (effects of temperature and hydrogen and effects of temperature and microstructure); evaluations of wide-panel aluminum alloy extrusions; Al-Si-Ge alloy development; effects of texture and precipitates on mechanical property anisotropy of Al-Cu-Mg-X alloys; damage evolution in polymeric composites; and environmental effects in fatigue life prediction - modeling crack propagation in light aerospace alloys.

  10. Displacement Theories for In-Flight Deformed Shape Predictions of Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Richards, W. L.; Tran, Van t.

    2007-01-01

    Displacement theories are developed for a variety of structures with the goal of providing real-time shape predictions for aerospace vehicles during flight. These theories are initially developed for a cantilever beam to predict the deformed shapes of the Helios flying wing. The main structural configuration of the Helios wing is a cantilever wing tubular spar subjected to bending, torsion, and combined bending and torsion loading. The displacement equations that are formulated are expressed in terms of strains measured at multiple sensing stations equally spaced on the surface of the wing spar. Displacement theories for other structures, such as tapered cantilever beams, two-point supported beams, wing boxes, and plates also are developed. The accuracy of the displacement theories is successfully validated by finite-element analysis and classical beam theory using input-strains generated by finite-element analysis. The displacement equations and associated strain-sensing system (such as fiber optic sensors) create a powerful means for in-flight deformation monitoring of aerospace structures. This method serves multiple purposes for structural shape sensing, loads monitoring, and structural health monitoring. Ultimately, the calculated displacement data can be visually displayed to the ground-based pilot or used as input to the control system to actively control the shape of structures during flight.

  11. Design and analysis of aerospace structures at elevated temperatures. [aircraft, missiles, and space platforms

    NASA Technical Reports Server (NTRS)

    Chang, C. I.

    1989-01-01

    An account is given of approaches that have emerged as useful in the incorporation of thermal loading considerations into advanced composite materials-based aerospace structural design practices. Sources of structural heating encompass not only propulsion system heat and aerodynamic surface heating at supersonic speeds, but the growing possibility of intense thermal fluxes from directed-energy weapons. The composite materials in question range from intrinsically nonheat-resistant polymer matrix systems to metal-matrix composites, and increasingly to such ceramic-matrix composites as carbon/carbon, which are explicitly intended for elevated temperature operation.

  12. Inelastic behavior of structural components

    NASA Technical Reports Server (NTRS)

    Hussain, N.; Khozeimeh, K.; Toridis, T. G.

    1980-01-01

    A more accurate procedure was developed for the determination of the inelastic behavior of structural components. The actual stress-strain curve for the mathematical of the structure was utilized to generate the force-deformation relationships for the structural elements, rather than using simplified models such as elastic-plastic, bilinear and trilinear approximations. relationships were generated for beam elements with various types of cross sections. In the generational of these curves, stress or load reversals, kinematic hardening and hysteretic behavior were taken into account. Intersections between loading and unloading branches were determined through an iterative process. Using the inelastic properties obtained, the plastic static response of some simple structural systems composed of beam elements was computed. Results were compared with known solutions, indicating a considerable improvement over response predictions obtained by means of simplified approximations used in previous investigations.

  13. Structural Studies of Ciliary Components

    PubMed Central

    Mizuno, Naoko; Taschner, Michael; Engel, Benjamin D.; Lorentzen, Esben

    2012-01-01

    Cilia are organelles found on most eukaryotic cells, where they serve important functions in motility, sensory reception, and signaling. Recent advances in electron tomography have facilitated a number of ultrastructural studies of ciliary components that have significantly improved our knowledge of cilium architecture. These studies have produced nanometer‐resolution structures of axonemal dynein complexes, microtubule doublets and triplets, basal bodies, radial spokes, and nexin complexes. In addition to these electron tomography studies, several recently published crystal structures provide insights into the architecture and mechanism of dynein as well as the centriolar protein SAS-6, important for establishing the 9-fold symmetry of centrioles. Ciliary assembly requires intraflagellar transport (IFT), a process that moves macromolecules between the tip of the cilium and the cell body. IFT relies on a large 20-subunit protein complex that is thought to mediate the contacts between ciliary motor and cargo proteins. Structural investigations of IFT complexes are starting to emerge, including the first three‐dimensional models of IFT material in situ, revealing how IFT particles organize into larger train-like arrays, and the high-resolution structure of the IFT25/27 subcomplex. In this review, we cover recent advances in the structural and mechanistic understanding of ciliary components and IFT complexes. PMID:22683354

  14. Vocabulary of aerospace safety terms pertaining to cryogenic safety, fires, explosions, and structure failure

    NASA Technical Reports Server (NTRS)

    Pelouch, J. J., Jr.; Mandel, G.; Ordin, P. M.

    1976-01-01

    This vocabulary listing characterizes the contents of over 10,000 documents of the NASA Aerospace Safety Research and Data Institute's (ASRDI) safety engineering collection. The ASRDI collection is now one of the series accessible on the NASA RECON data base. There are approximately 6,300 postable terms that describe literature in the areas of cryogenic fluid safety, specifically hydrogen, oxygen, liquified natural gas; fire and explosion technology; and the mechanics of structural failure. To facilitate the proper selection of information nonpostable, related and array terms have been included in this listing.

  15. NDE of Fiber Reinforced Foam Composite Structures for Future Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Walker, james; Roth, Don; Hopkins, Dale

    2010-01-01

    This slide presentation reviews the complexities of non-destructive evaluation (NDE) of fiber reinforced foam composite structures to be used for aerospace vehicles in the future.Various views of fiber reinforced foam materials are shown and described. Conventional methods of NDE for composites are reviewed such as Micro-computed X-Ray Tomography, Thermography, Shearography, and Phased Array Ultrasonics (PAUT). These meth0ods appear to work well on the face sheet and face sheet ot core bond, they do not provide adequate coverage for the webs. There is a need for additional methods that will examine the webs and web to foam core bond.

  16. Research of aluminium alloy aerospace structure aperture measurement based on 3D digital speckle correlation method

    NASA Astrophysics Data System (ADS)

    Bai, Lu; Wang, Hongbo; Zhou, Jiangfan; Yang, Rong; Zhang, Hui

    2014-11-01

    In this paper, the aperture change of the aluminium alloy aerospace structure under real load is researched. Static experiments are carried on which is simulated the load environment of flight course. Compared with the traditional methods, through experiments results, it's proved that 3D digital speckle correlation method has good adaptability and precision on testing aperture change, and it can satisfy measurement on non-contact,real-time 3D deformation or stress concentration. The test results of new method is compared with the traditional method.

  17. Estimation of probability of failure for damage-tolerant aerospace structures

    NASA Astrophysics Data System (ADS)

    Halbert, Keith

    dissertation describes and develops new PDTA methodologies that directly address the deficiencies of the currently used tools. The new methods are implemented as a free, publicly licensed and open source R software package that can be downloaded from the Comprehensive R Archive Network. The tools consist of two main components. First, an explicit (and expensive) Monte Carlo approach is presented which simulates the life of an aircraft structural component flight-by-flight. This straightforward MC routine can be used to provide defensible estimates of the failure probabilities for future flights and repair probabilities for future inspections under a variety of failure and maintenance scenarios. This routine is intended to provide baseline estimates against which to compare the results of other, more efficient approaches. Second, an original approach is described which models the fatigue process and future scheduled inspections as a hidden Markov model. This model is solved using a particle-based approximation and the sequential importance sampling algorithm, which provides an efficient solution to the PDTA problem. Sequential importance sampling is an extension of importance sampling to a Markov process, allowing for efficient Bayesian updating of model parameters. This model updating capability, the benefit of which is demonstrated, is lacking in other PDTA approaches. The results of this approach are shown to agree with the results of the explicit Monte Carlo routine for a number of PDTA problems. Extensions to the typical PDTA problem, which cannot be solved using currently available tools, are presented and solved in this work. These extensions include incorporating observed evidence (such as non-destructive inspection results), more realistic treatment of possible future repairs, and the modeling of failure involving more than one crack (the so-called continuing damage problem). The described hidden Markov model / sequential importance sampling approach to PDTA has the

  18. Smart electronics with interdigital electrodes, antennas, and MEMS for aerospace structures

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1995-05-01

    A remote local and global sensing and control of aerospace structures using advanced polymeric smart materials, MEMS, and built-in antennas is presented. The sensors are fabricated with interdigital transducers printed on a piezoelectric polymer. They in turn are mounted onto an ultrathin Penn State novel RF antenna (patent filed). The sensors are designed to measure both pressure and shear of the fluid flow on aerospace structures. The wave form measurements may be monitored at a remote location either at the cockpit or elsewhere via the antennas in the sensors and an outside antenna. The integrated MEMS actuators, which are comprised of cantilever-, diaphragm-, and microbridge-based MEMS with suitable smart electronics etched onto the structure, are controlled by the built-in antennas through feedback and feedforward control architecture. The integration of such materials and smart electronics into the skin of airfoil is ideal for sensing and controlling drag. The basic idea of this concept involves detection of the point of transition from laminar to turbulent flow and transmitting acoustical energy into the boundary layer so that the low-energy fluid particles accelerate in the transverse direction and mix with the high energy flow outside of the boundary layer. The use of the present smart materials and electronics for active noise control and EMI suppression in aircraft and helicopters is also outlines.

  19. Manufacturing Challenges Associated with the Use of Metal Matrix Composites in Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Prater, Tracie

    2014-01-01

    Metal Matrix Composites (MMCs) consist of a metal alloy reinforced with ceramic particles or fibers. These materials possess a very high strength to weight ratio, good resistance to impact and wear, and a number of other properties which make them attractive for use in aerospace and defense applications. MMCs have found use in the space shuttle orbiter's structural tubing, the Hubble Space Telescope's antenna mast, control surfaces and propulsion systems for aircraft, and tank armors. The size of MMC components is severely limited by difficulties encountered in joining these materials using fusion welding. Melting of the material results in formation of an undesirable phase (formed when molten Aluminum reacts with the reinforcement) which leaves a strength depleted region along the joint line. Friction Stir Welding (FSW) is a relatively nascent solid state joining technique developed at The Welding Institute (TWI) in 1991. The process was first used at NASA to weld the super lightweight external tank for the Space Shuttle. Today FSW is used to join structural components of the Delta IV, Atlas V, and Falcon IX rockets as well as NASA's Orion Crew Exploration Vehicle and Space Launch System. A current focus of FSW research is to extend the process to new materials, such as MMCs, which are difficult to weld using conventional fusion techniques. Since Friction Stir Welding occurs below the melting point of the workpiece material, this deleterious phase is absent in FSW-ed MMC joints. FSW of MMCs is, however, plagued by rapid wear of the welding tool, a consequence of the large discrepancy in hardness between the steel tool and the reinforcement material. This chapter summarizes the challenges encountered when joining MMCs to themselves or to other materials in structures. Specific attention is paid to the influence of process variables in Friction Stir Welding on the wear process characterizes the effect of process parameters (spindle speed, traverse rate, and length

  20. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST)

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Scully, John R.; Stoner, Glenn E.; Thornton, Earl A.; Wawner, Franklin E., Jr.; Wert, John A.

    1993-01-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program continues a high level of activity. Progress achieved between 1 Jan. and 30 Jun. 1993 is reported. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The following projects are addressed: environmental fatigue of Al-Li-Cu alloys; mechanisms of localized corrosion and environmental fracture in Al-Cu-Li-Mg-Ag alloy X2095 and compositional variations; the effect of zinc additions on the precipitation and stress corrosion cracking behavior of alloy 8090; hydrogen interactions with Al-Li-Cu alloy 2090 and model alloys; metastable pitting of aluminum alloys; cryogenic fracture toughness of Al-Cu-Li + In alloys; the fracture toughness of Weldalite (TM); elevated temperature cracking of advanced I/M aluminum alloys; response of Ti-1100/SCS-6 composites to thermal exposure; superplastic forming of Weldalite (TM); research to incorporate environmental effects into fracture mechanics fatigue life prediction codes such as NASA FLAGRO; and thermoviscoplastic behavior.

  1. Aerospace Community. Aerospace Education I.

    ERIC Educational Resources Information Center

    Mickey, V. V.

    This book, one in the series on Aerospace Education I, emphasizes the two sides of aerospace--military aerospace and civilian aerospace. Chapter 1 includes a brief discussion on the organization of Air Force bases and missile sites in relation to their missions. Chapter 2 examines the community services provided by Air Force bases. The topics…

  2. An Assessment of Nondestructive Evaluation Capability for Complex Additive Manufacturing Aerospace Components

    NASA Technical Reports Server (NTRS)

    Walker, James; Beshears, Ron; Lambert, Dennis; Tilson, William

    2016-01-01

    The primary focus of this work is to investigate some of the fundamental relationships between processing, mechanical testing, materials characterization, and NDE for additively manufactured (AM) components using the powder bed fusion direct melt laser sintered process. The goal is to understand the criticality of defects unique to the AM process and then how conventional nondestructive evaluation methods as well as some of the more non-traditional methods such as computed tomography, are effected by the AM material. Specific defects including cracking, porosity and partially/unfused powder will be addressed. Besides line-of-site NDE, as appropriate these inspection capabilities will be put into the context of complex AM geometries where hidden features obscure, or inhibit traditional NDE methods.

  3. Aerospace Education. NSTA Position Statement

    ERIC Educational Resources Information Center

    National Science Teachers Association (NJ1), 2008

    2008-01-01

    National Science Teachers Association (NSTA) has developed a new position statement, "Aerospace Education." NSTA believes that aerospace education is an important component of comprehensive preK-12 science education programs. This statement highlights key considerations that should be addressed when implementing a high quality aerospace education…

  4. Smart structures in engineering and technology: an aerospace and automotive perspective

    NASA Astrophysics Data System (ADS)

    Boller, Christian

    2003-03-01

    This paper gives an overview on what was expected to be achieved in smart structures and materials for aerospace and automotive applications about a decade ago and what so far could be achieved. Although initial goals turned out to be somewhat over-ambitious, achievements so far are worth to be discussed and pursued. Major ongoing activities being on the verge to be transferred into application are therefore summarized and referenced. A major lack in smart structures technology transfer has been identified being procedures on how to identify which technologies have the most likely chance to be transferred into application. A procedure for this successfully applied in market research and product development is therefore described and proposed here.

  5. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST). Progress Report, 1 Jan. - 30 Jun. 1991

    SciTech Connect

    Not Available

    1991-06-01

    The general objective of the Light Aerospace Alloy and Structures Technology (LA2ST) Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and associated thermal gradient structures in close collaboration with Langley researchers. Specific technical objectives are established for each research project. Relevant data and basic understanding of material behavior and microstructure, new monolithic and composite alloys, advanced processing methods, new solid and fluid mechanic analyses, measurement advances, and a pool of educated graduate students are sought.

  6. A Program of Research and Education in Aerospace Structures at the Joint Institute for Advancement of Flight Sciences

    NASA Technical Reports Server (NTRS)

    Tolson, Robert H.

    2000-01-01

    The objectives of the cooperative effort with NASA was to conduct research related to aerospace structures and to increase the quality and quantity of highly trained engineers knowledgeable about aerospace structures. The program has successfully met the objectives and has been of significant benefit to NASA LARC, the GWU and the nation. The program was initiated with 3 students in 1994 under the direction of Dr. Robert Tolson as the Principal Investigator. Since initiation, 14 students have been involved in the program, resulting in 11 MS degrees with 2 more expected in 2000. The 11 MS theses and projects are listed. For technology transfer purposes some research is not reported in thesis form. Graduates from the program have been hired at aerospace and other companies across the nation, providing GWU and LARC with important industry and government contacts.

  7. Spatial scanning for anomaly detection in acoustic emission testing of an aerospace structure

    NASA Astrophysics Data System (ADS)

    Hensman, James; Worden, Keith; Eaton, Mark; Pullin, Rhys; Holford, Karen; Evans, Sam

    2011-10-01

    Acoustic emission (AE) monitoring of engineering structures potentially provides a convenient, cost-effective means of performing structural health monitoring. Networks of AE sensors can be easily and unobtrusively installed upon structures, giving the ability to detect and locate damage-related strain releases ('events') in the structure. Use of the technique is not widespread due to the lack of a simple and effective method for detecting abnormal activity levels: the sensitivity of AE sensor networks is such that events unrelated to damage are prevalent in most applications. In this publication, we propose to monitor AE activity in a structure using a spatial scanning statistic, developed and used effectively in the field of epidemiology. The technique is demonstrated on an aerospace structure - an Airbus A320 main landing gear fitting - undergoing fatigue loading, and the method is compared to existing techniques. Despite its simplicity, the scanning statistic proves to be an extremely effective tool in detecting the onset of damage in the structure: it requires little to no user intervention or expertise, is inexpensive to compute and has an easily interpretable output. Furthermore, the generic nature of the method allows the technique to be used in a variety of monitoring scenarios, to detect damage in a wide range of structures.

  8. Aerospace Medicine

    NASA Technical Reports Server (NTRS)

    Michaud, Vince

    2015-01-01

    NASA Aerospace Medicine overview - Aerospace Medicine is that specialty area of medicine concerned with the determination and maintenance of the health, safety, and performance of those who fly in the air or in space.

  9. Toward smart aerospace structures: design of a piezoelectric sensor and its analog interface for flaw detection.

    PubMed

    Boukabache, Hamza; Escriba, Christophe; Fourniols, Jean-Yves

    2014-01-01

    Structural health monitoring using noninvasive methods is one of the major challenges that aerospace manufacturers face in this decade. Our work in this field focuses on the development and the system integration of millimetric piezoelectric sensors/ actuators to generate and measure specific guided waves. The aim of the application is to detect mechanical flaws on complex composite and alloy structures to quantify efficiently the global structures' reliability. The study begins by a physical and analytical analysis of a piezoelectric patch. To preserve the structure's integrity, the transducers are directly pasted onto the surface which leads to a critical issue concerning the interfacing layer. In order to improve the reliability and mitigate the influence of the interfacing layer, the global equations of piezoelectricity are coupled with a load transfer model. Thus we can determine precisely the shear strain developed on the surface of the structure. To exploit the generated signal, a high precision analog charge amplifier coupled to a double T notch filter were designed and scaled. Finally, a novel joined time-frequency analysis based on a wavelet decomposition algorithm is used to extract relevant structures signatures. Finally, this paper provides examples of application on aircraft structure specimens and the feasibility of the system is thus demonstrated. PMID:25365457

  10. Toward Smart Aerospace Structures: Design of a Piezoelectric Sensor and Its Analog Interface for Flaw Detection

    PubMed Central

    Boukabache, Hamza; Escriba, Christophe; Fourniols, Jean-Yves

    2014-01-01

    Structural health monitoring using noninvasive methods is one of the major challenges that aerospace manufacturers face in this decade. Our work in this field focuses on the development and the system integration of millimetric piezoelectric sensors/ actuators to generate and measure specific guided waves. The aim of the application is to detect mechanical flaws on complex composite and alloy structures to quantify efficiently the global structures' reliability. The study begins by a physical and analytical analysis of a piezoelectric patch. To preserve the structure's integrity, the transducers are directly pasted onto the surface which leads to a critical issue concerning the interfacing layer. In order to improve the reliability and mitigate the influence of the interfacing layer, the global equations of piezoelectricity are coupled with a load transfer model. Thus we can determine precisely the shear strain developed on the surface of the structure. To exploit the generated signal, a high precision analog charge amplifier coupled to a double T notch filter were designed and scaled. Finally, a novel joined time-frequency analysis based on a wavelet decomposition algorithm is used to extract relevant structures signatures. Finally, this paper provides examples of application on aircraft structure specimens and the feasibility of the system is thus demonstrated. PMID:25365457

  11. Aerospace - Aviation Education.

    ERIC Educational Resources Information Center

    Martin, Arthur I.; Jones, K. K.

    This document outlines the aerospace-aviation education program of the State of Texas. In this publication the course structures have been revised to fit the quarter system format of secondary schools in Texas. The four courses outlined here have been designed for students who will be consumers of aerospace products, spinoffs, and services or who…

  12. Collection, processing, and reporting of damage tolerant design data for non-aerospace structural materials

    NASA Technical Reports Server (NTRS)

    Huber, P. D.; Gallagher, J. P.

    1994-01-01

    This report describes the organization, format and content of the NASA Johnson damage tolerant database which was created to store damage tolerant property data for non aerospace structural materials. The database is designed to store fracture toughness data (K(sub IC), K(sub c), J(sub IC) and CTOD(sub IC)), resistance curve data (K(sub R) VS. delta a (sub eff) and JR VS. delta a (sub eff)), as well as subcritical crack growth data (a vs. N and da/dN vs. delta K). The database contains complementary material property data for both stainless and alloy steels, as well as for aluminum, nickel, and titanium alloys which were not incorporated into the Damage Tolerant Design Handbook database.

  13. Method for Estimating Operational Loads on Aerospace Structures Using Span-Wisely Distributed Surface Strains

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Fleischer, Van Tran

    2013-01-01

    This report presents a new method for estimating operational loads (bending moments, shear loads, and torques) acting on slender aerospace structures using distributed surface strains (unidirectional strains). The surface strain-sensing stations are to be evenly distributed along each span-wise strain-sensing line. A depth-wise cross section of the structure along each strain-sensing line can then be considered as an imaginary embedded beam. The embedded beam was first evenly divided into multiple small domains with domain junctures matching the strain-sensing stations. The new method is comprised of two steps. The first step is to determine the structure stiffness (bending or torsion) using surface strains obtained from a simple bending (or torsion) loading case, for which the applied bending moment (or torque) is known. The second step is to use the strain-determined structural stiffness (bending or torsion), and a new set of surface strains induced by any other loading case to calculate the associated operational loads (bending moments, shear loads, or torques). Performance of the new method for estimating operational loads was studied in light of finite-element analyses of several example structures subjected to different loading conditions. The new method for estimating operational loads was found to be fairly accurate, and is very promising for applications to the flight load monitoring of flying vehicles with slender wings.

  14. Further Development of Ko Displacement Theory for Deformed Shape Predictions of Nonuniform Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Fleischer, Van Tran

    2009-01-01

    The Ko displacement theory previously formulated for deformed shape predictions of nonuniform beam structures is further developed mathematically. The further-developed displacement equations are expressed explicitly in terms of geometrical parameters of the beam and bending strains at equally spaced strain-sensing stations along the multiplexed fiber-optic sensor line installed on the bottom surface of the beam. The bending strain data can then be input into the displacement equations for calculations of local slopes, deflections, and cross-sectional twist angles for generating the overall deformed shapes of the nonuniform beam. The further-developed displacement theory can also be applied to the deformed shape predictions of nonuniform two-point supported beams, nonuniform panels, nonuniform aircraft wings and fuselages, and so forth. The high degree of accuracy of the further-developed displacement theory for nonuniform beams is validated by finite-element analysis of various nonuniform beam structures. Such structures include tapered tubular beams, depth-tapered unswept and swept wing boxes, width-tapered wing boxes, and double-tapered wing boxes, all under combined bending and torsional loads. The Ko displacement theory, combined with the fiber-optic strain-sensing system, provide a powerful tool for in-flight deformed shape monitoring of unmanned aerospace vehicles by ground-based pilots to maintain safe flights.

  15. NASA-UVA light aerospace alloy and structures technology program (LA2ST). Progress report, 1 July-31 December 1993

    SciTech Connect

    Gangloff, R.P.; Scully, J.R.; Starke, E.A. Jr.; Stoner, G.E.; Thornton, E.A.; Wawner, F.E. Jr.; Wert, J.A.

    1994-03-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986, and continues a high level of activity, with projects being conducted by graduate students and faculty advisors in the Departments of Materials Science and Engineering, and Mechanical and Aerospace Engineering at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, the authors report on progress achieved between July 1 and December 31, 1993. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. Projects generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and critically, a pool of educated graduate students for aerospace technologies.

  16. Using Aerospace Technology To Design Orthopedic Implants

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.; Mraz, P. J.; Davy, D. T.

    1996-01-01

    Technology originally developed to optimize designs of composite-material aerospace structural components used to develop method for optimizing designs of orthopedic implants. Development effort focused on designing knee implants, long-term goal to develop method for optimizing designs of orthopedic implants in general.

  17. A Survey of Emerging Materials for Revolutionary Aerospace Vehicle Structures and Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Shuart, Mark J.; Gray, Hugh R.

    2002-01-01

    The NASA Strategic Plan identifies the long-term goal of providing safe and affordable space access, orbital transfer, and interplanetary transportation capabilities to enable scientific research, human, and robotic exploration, and the commercial development of space. Numerous scientific and engineering breakthroughs will be required to develop the technology required to achieve this goal. Critical technologies include advanced vehicle primary and secondary structure, radiation protection, propulsion and power systems, fuel storage, electronics and devices, sensors and science instruments, and medical diagnostics and treatment. Advanced materials with revolutionary new capabilities are an essential element of each of these technologies. A survey of emerging materials with applications to aerospace vehicle structures and propulsion systems was conducted to assist in long-term Agency mission planning. The comprehensive survey identified materials already under development that could be available in 5 to 10 years and those that are still in the early research phase and may not be available for another 20 to 30 years. The survey includes typical properties, a description of the material and processing methods, the current development status, and the critical issues that must be overcome to achieve commercial viability.

  18. Reliability-based econometrics of aerospace structural systems: Design criteria and test options. Ph.D. Thesis - Georgia Inst. of Tech.

    NASA Technical Reports Server (NTRS)

    Thomas, J. M.; Hanagud, S.

    1974-01-01

    The design criteria and test options for aerospace structural reliability were investigated. A decision methodology was developed for selecting a combination of structural tests and structural design factors. The decision method involves the use of Bayesian statistics and statistical decision theory. Procedures are discussed for obtaining and updating data-based probabilistic strength distributions for aerospace structures when test information is available and for obtaining subjective distributions when data are not available. The techniques used in developing the distributions are explained.

  19. Fiber Bragg Grating Sensor System for Monitoring Smart Composite Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Moslehi, Behzad; Black, Richard J.; Gowayed, Yasser

    2012-01-01

    Lightweight, electromagnetic interference (EMI) immune, fiber-optic, sensor- based structural health monitoring (SHM) will play an increasing role in aerospace structures ranging from aircraft wings to jet engine vanes. Fiber Bragg Grating (FBG) sensors for SHM include advanced signal processing, system and damage identification, and location and quantification algorithms. Potentially, the solution could be developed into an autonomous onboard system to inspect and perform non-destructive evaluation and SHM. A novel method has been developed to massively multiplex FBG sensors, supported by a parallel processing interrogator, which enables high sampling rates combined with highly distributed sensing (up to 96 sensors per system). The interrogation system comprises several subsystems. A broadband optical source subsystem (BOSS) and routing and interface module (RIM) send light from the interrogation system to a composite embedded FBG sensor matrix, which returns measurand-dependent wavelengths back to the interrogation system for measurement with subpicometer resolution. In particular, the returned wavelengths are channeled by the RIM to a photonic signal processing subsystem based on powerful optical chips, then passed through an optoelectronic interface to an analog post-detection electronics subsystem, digital post-detection electronics subsystem, and finally via a data interface to a computer. A range of composite structures has been fabricated with FBGs embedded. Stress tensile, bending, and dynamic strain tests were performed. The experimental work proved that the FBG sensors have a good level of accuracy in measuring the static response of the tested composite coupons (down to submicrostrain levels), the capability to detect and monitor dynamic loads, and the ability to detect defects in composites by a variety of methods including monitoring the decay time under different dynamic loading conditions. In addition to quasi-static and dynamic load monitoring, the

  20. A self-diagnostic adhesive for monitoring bonded joints in aerospace structures

    NASA Astrophysics Data System (ADS)

    Zhuang, Yitao; Li, Yu-hung; Kopsaftopoulos, Fotis; Chang, Fu-Kuo

    2016-04-01

    Bondline integrity is still one of the most critical concerns in the design of aircraft structures up to date. Due to the lack of confidence on the integrity of the bondline both during fabrication and service, the industry standards and regulations still require assembling the composite using conventional fasteners. Furthermore, current state-of-the-art non-destructive evaluation (NDE) and structural health monitoring (SHM) techniques are incapable of offering mature solutions on the issue of bondline integrity monitoring. Therefore, the objective of this work is the development of an intelligent adhesive film with integrated micro-sensors for monitoring the integrity of the bondline interface. The proposed method makes use of an electromechanical-impedance (EMI) based method, which is a rapidly evolving approach within the SHM family. Furthermore, an innovative screen-printing technique to fabricate piezoelectric ceramic sensors with minimal thickness has been developed at Stanford. The approach presented in this study is based on the use of (i) micro screen-printed piezoelectric sensors integrated into adhesive leaving a minimal footprint on the material, (ii) numerical and analytical modeling of the EMI spectrum of the adhesive bondline, (iii) novel diagnostic algorithms for monitoring the bondline integrity based on advanced signal processing techniques, and (iv) the experimental assessment via prototype adhesively bonded structures in static (varying loads) and dynamic (fatigue) environments. The proposed method will provide a huge confidence on the use of bonded joints for aerospace structures and lead to a paradigm change in their design by enabling enormous weight savings while maximizing the economic and performance efficiency.

  1. Structured Functional Principal Component Analysis

    PubMed Central

    Shou, Haochang; Zipunnikov, Vadim; Crainiceanu, Ciprian M.; Greven, Sonja

    2015-01-01

    Summary Motivated by modern observational studies, we introduce a class of functional models that expand nested and crossed designs. These models account for the natural inheritance of the correlation structures from sampling designs in studies where the fundamental unit is a function or image. Inference is based on functional quadratics and their relationship with the underlying covariance structure of the latent processes. A computationally fast and scalable estimation procedure is developed for high-dimensional data. Methods are used in applications including high-frequency accelerometer data for daily activity, pitch linguistic data for phonetic analysis, and EEG data for studying electrical brain activity during sleep. PMID:25327216

  2. Structured functional principal component analysis.

    PubMed

    Shou, Haochang; Zipunnikov, Vadim; Crainiceanu, Ciprian M; Greven, Sonja

    2015-03-01

    Motivated by modern observational studies, we introduce a class of functional models that expand nested and crossed designs. These models account for the natural inheritance of the correlation structures from sampling designs in studies where the fundamental unit is a function or image. Inference is based on functional quadratics and their relationship with the underlying covariance structure of the latent processes. A computationally fast and scalable estimation procedure is developed for high-dimensional data. Methods are used in applications including high-frequency accelerometer data for daily activity, pitch linguistic data for phonetic analysis, and EEG data for studying electrical brain activity during sleep. PMID:25327216

  3. Structural interaction of cytoskeletal components.

    PubMed

    Schliwa, M; van Blerkom, J

    1981-07-01

    Three-dimensional cytoskeletal organization of detergent-treated epithelial African green monkey kidney cells (BSC-1) and chick embryo fibroblasts was studied in whole-mount preparations visualized in a high voltage electron microscope. Stereo images are generated at both low and high magnification to reveal both overall cytoskeletal morphology and details of the structural continuity of different filament types. By the use of an improved extraction procedure in combination with heavy meromyosin subfragment 1 decoration of actin filaments, several new features of filament organization are revealed that suggest that the cytoskeleton is a highly interconnected structural unit. In addition to actin filaments, intermediate filaments, and microtubules, a new class of filaments of 2- to 3-nm diameter and 30- to 300-nm length that do not bind heavy merymyosin is demonstrated. They form end-to-side contacts with other cytoskeletal filaments, thereby acting as linkers between various fibers, both like (e.g., actin- actin) and unlike (e.g., actin-intermediate filament, intermediate filament-microtubule). Their nature is unknown. In addition to 2- to 3-nm filaments, actin filaments are demonstrated to form end-to-side contacts with other filaments. Y-shaped actin filament "branches" are observed both in the cell periphery close to ruffles and in more central cell areas also populated by abundant intermediate filaments and microtubules. Arrowhead complexes formed by subfragment 1 decoration of actin filaments point towards the contact site. Actin filaments also form end-to-side contacts with microtubules and intermediate filaments. Careful inspection of numerous actin-microtubule contacts shows that microtubules frequently change their course at sites of contact. A variety of experimentally induced modifications of the frequency of actin-microtubule contacts can be shown to influence the course of microtubules. We conclude that bends in microtubules are imposed by structural

  4. Generalized Structured Component Analysis with Latent Interactions

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Ho, Moon-Ho Ringo; Lee, Jonathan

    2010-01-01

    Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling. In practice, researchers may often be interested in examining the interaction effects of latent variables. However, GSCA has been geared only for the specification and testing of the main effects of variables. Thus, an extension of GSCA…

  5. Optical Information Processing for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Current research in optical processing is reviewed. Its role in future aerospace systems is determined. The development of optical devices and components demonstrates that system concepts can be implemented in practical aerospace configurations.

  6. Military Aerospace. Aerospace Education II.

    ERIC Educational Resources Information Center

    Smith, J. C.

    This book is a revised publication in the series on Aerospace Education II. It describes the employment of aerospace forces, their methods of operation, and some of the weapons and equipment used in combat and combat support activities. The first chapter describes some of the national objectives and policies served by the Air Force in peace and…

  7. Aerospace Environment. Aerospace Education I.

    ERIC Educational Resources Information Center

    Savler, D. S.; Smith, J. C.

    This book is one in the series on Aerospace Education I. It briefly reviews current knowledge of the universe, the earth and its life-supporting atmosphere, and the arrangement of celestial bodies in outer space and their physical characteristics. Chapter 1 includes a brief survey of the aerospace environment. Chapters 2 and 3 examine the…

  8. Experimental Modal Analysis and Dynaic Strain Fiber Bragg Gratings for Structural Health Monitoring of Composite Aerospace Structures

    NASA Astrophysics Data System (ADS)

    Panopoulou, A.; Fransen, S.; Gomez Molinero, V.; Kostopoulos, V.

    2012-07-01

    The objective of this work is to develop a new structural health monitoring system for composite aerospace structures based on dynamic response strain measurements and experimental modal analysis techniques. Fibre Bragg Grating (FBG) optical sensors were used for monitoring the dynamic response of the composite structure. The structural dynamic behaviour has been numerically simulated and experimentally verified by means of vibration testing. The hypothesis of all vibration tests was that actual damage in composites reduces their stiffness and produces the same result as mass increase produces. Thus, damage was simulated by slightly varying locally the mass of the structure at different zones. Experimental modal analysis based on the strain responses was conducted and the extracted strain mode shapes were the input for the damage detection expert system. A feed-forward back propagation neural network was the core of the damage detection system. The features-input to the neural network consisted of the strain mode shapes, extracted from the experimental modal analysis. Dedicated training and validation activities were carried out based on the experimental results. The system showed high reliability, confirmed by the ability of the neural network to recognize the size and the position of damage on the structure. The experiments were performed on a real structure i.e. a lightweight antenna sub- reflector, manufactured and tested at EADS CASA ESPACIO. An integrated FBG sensor network, based on the advantage of multiplexing, was mounted on the structure with optimum topology. Numerical simulation of both structures was used as a support tool at all the steps of the work. Potential applications for the proposed system are during ground qualification extensive tests of space structures and during the mission as modal analysis tool on board, being able via the FBG responses to identify a potential failure.

  9. Improved Joining of Metal Components to Composite Structures

    NASA Technical Reports Server (NTRS)

    Semmes, Edmund

    2009-01-01

    Systems requirements for complex spacecraft drive design requirements that lead to structures, components, and/or enclosures of a multi-material and multifunctional design. The varying physical properties of aluminum, tungsten, Invar, or other high-grade aerospace metals when utilized in conjunction with lightweight composites multiply system level solutions. These multi-material designs are largely dependent upon effective joining techAn improved method of joining metal components to matrix/fiber composite material structures has been invented. The method is particularly applicable to equipping such thin-wall polymer-matrix composite (PMC) structures as tanks with flanges, ceramic matrix composite (CMC) liners for high heat engine nozzles, and other metallic-to-composite attachments. The method is oriented toward new architectures and distributing mechanical loads as widely as possible in the vicinities of attachment locations to prevent excessive concentrations of stresses that could give rise to delaminations, debonds, leaks, and other failures. The method in its most basic form can be summarized as follows: A metal component is to be joined to a designated attachment area on a composite-material structure. In preparation for joining, the metal component is fabricated to include multiple studs projecting from the aforementioned face. Also in preparation for joining, holes just wide enough to accept the studs are molded into, drilled, or otherwise formed in the corresponding locations in the designated attachment area of the uncured ("wet') composite structure. The metal component is brought together with the uncured composite structure so that the studs become firmly seated in the holes, thereby causing the composite material to become intertwined with the metal component in the joining area. Alternately, it is proposed to utilize other mechanical attachment schemes whereby the uncured composite and metallic parts are joined with "z-direction" fasteners. The

  10. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST). Progress report, 1 January-30 June 1994

    SciTech Connect

    Gangloff, R.P.

    1994-07-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program was initiated in 1986 and continues with a high level of activity. Projects are being conducted by graduate students and faculty advisors in the Department of Materials Science and Engineering, as well as in the Department of Civil Engineering and Applied Mechanics, at the University of Virginia. This work is funded by the NASA-Langley Research Center under Grant NAG-1-745. Here, the authors report on progress achieved between January 1 and June 30, 1994. These results were presented at the Fifth Annual NASA LA2ST Grant Review Meeting held at the Langley Research Center in July of 1994. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, lightweight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. Specific technical objectives are presented for each research project. The authors generally aim to produce relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies.

  11. Organizational structure and operation of defense/aerospace information centers in the United States of America

    NASA Technical Reports Server (NTRS)

    Sauter, H. E.; Lushina, L. N.

    1983-01-01

    U.S. Government aerospace and defense information centers are addressed. DTIC and NASA are described in terms of their history, operational authority, information services provided, user community, sources of information collected, efforts under way to improve services, and external agreements regarding the exchange of documents and/or data bases. Contents show how DTIC and NASA provide aerospace/defense information services in support of U.S. research and development efforts. In a general introduction, the importance of scientific and technical information and the need for information centers to acquire, handle, and disseminate it are stressed.

  12. Probabilistic evaluation of SSME structural components

    NASA Astrophysics Data System (ADS)

    Rajagopal, K. R.; Newell, J. F.; Ho, H.

    1991-05-01

    The application is described of Composite Load Spectra (CLS) and Numerical Evaluation of Stochastic Structures Under Stress (NESSUS) family of computer codes to the probabilistic structural analysis of four Space Shuttle Main Engine (SSME) space propulsion system components. These components are subjected to environments that are influenced by many random variables. The applications consider a wide breadth of uncertainties encountered in practice, while simultaneously covering a wide area of structural mechanics. This has been done consistent with the primary design requirement for each component. The probabilistic application studies are discussed using finite element models that have been typically used in the past in deterministic analysis studies.

  13. Aerospace Technology.

    ERIC Educational Resources Information Center

    Paschke, Jean; And Others

    1991-01-01

    Describes the Sauk Rapids (Minnesota) High School aviation and aerospace curriculum that was developed by Curtis Olson and the space program developed by Gerald Mayall at Philadelphia's Northeast High School. Both were developed in conjunction with NASA. (JOW)

  14. Structural Analysis Methods for Structural Health Management of Future Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Tessler, Alexander

    2007-01-01

    Two finite element based computational methods, Smoothing Element Analysis (SEA) and the inverse Finite Element Method (iFEM), are reviewed, and examples of their use for structural health monitoring are discussed. Due to their versatility, robustness, and computational efficiency, the methods are well suited for real-time structural health monitoring of future space vehicles, large space structures, and habitats. The methods may be effectively employed to enable real-time processing of sensing information, specifically for identifying three-dimensional deformed structural shapes as well as the internal loads. In addition, they may be used in conjunction with evolutionary algorithms to design optimally distributed sensors. These computational tools have demonstrated substantial promise for utilization in future Structural Health Management (SHM) systems.

  15. An optimality criterion for sizing members of heated structures with temperature constraints. [considering aerospace structures

    NASA Technical Reports Server (NTRS)

    Rao, G. V.; Shore, C. P.; Narayanaswami, R.

    1977-01-01

    A thermal optimality criterion is presented for sizing members of heated structures with multiple temperature constraints. The optimality criterion is similar to an existing optimality criterion for design of mechanically loaded structures with displacement constraints. Effectiveness of the thermal optimality criterion is assessed by applying it to one- and two-dimensional thermal problems where temperatures can be controlled by varying the material distribution in the structure. Results obtained from the optimality criterion agree within 2 percent with results from a closed-form solution and with results from a mathematical programming technique. The thermal optimality criterion augments existing optimality criteria for strength and stiffness related constraints and offers the possibility of extension of optimality techniques to sizing structures with combined thermal and mechanical loading.

  16. An Inverse Interpolation Method Utilizing In-Flight Strain Measurements for Determining Loads and Structural Response of Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Shkarayev, S.; Krashantisa, R.; Tessler, A.

    2004-01-01

    An important and challenging technology aimed at the next generation of aerospace vehicles is that of structural health monitoring. The key problem is to determine accurately, reliably, and in real time the applied loads, stresses, and displacements experienced in flight, with such data establishing an information database for structural health monitoring. The present effort is aimed at developing a finite element-based methodology involving an inverse formulation that employs measured surface strains to recover the applied loads, stresses, and displacements in an aerospace vehicle in real time. The computational procedure uses a standard finite element model (i.e., "direct analysis") of a given airframe, with the subsequent application of the inverse interpolation approach. The inverse interpolation formulation is based on a parametric approximation of the loading and is further constructed through a least-squares minimization of calculated and measured strains. This procedure results in the governing system of linear algebraic equations, providing the unknown coefficients that accurately define the load approximation. Numerical simulations are carried out for problems involving various levels of structural approximation. These include plate-loading examples and an aircraft wing box. Accuracy and computational efficiency of the proposed method are discussed in detail. The experimental validation of the methodology by way of structural testing of an aircraft wing is also discussed.

  17. New Parallel Algorithms for Structural Analysis and Design of Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Nguyen, Duc T.

    1998-01-01

    Subspace and Lanczos iterations have been developed, well documented, and widely accepted as efficient methods for obtaining p-lowest eigen-pair solutions of large-scale, practical engineering problems. The focus of this paper is to incorporate recent developments in vectorized sparse technologies in conjunction with Subspace and Lanczos iterative algorithms for computational enhancements. Numerical performance, in terms of accuracy and efficiency of the proposed sparse strategies for Subspace and Lanczos algorithm, is demonstrated by solving for the lowest frequencies and mode shapes of structural problems on the IBM-R6000/590 and SunSparc 20 workstations.

  18. Review of the probabilistic failure analysis methodology and other probabilistic approaches for application in aerospace structural design

    NASA Technical Reports Server (NTRS)

    Townsend, J.; Meyers, C.; Ortega, R.; Peck, J.; Rheinfurth, M.; Weinstock, B.

    1993-01-01

    Probabilistic structural analyses and design methods are steadily gaining acceptance within the aerospace industry. The safety factor approach to design has long been the industry standard, and it is believed by many to be overly conservative and thus, costly. A probabilistic approach to design may offer substantial cost savings. This report summarizes several probabilistic approaches: the probabilistic failure analysis (PFA) methodology developed by Jet Propulsion Laboratory, fast probability integration (FPI) methods, the NESSUS finite element code, and response surface methods. Example problems are provided to help identify the advantages and disadvantages of each method.

  19. Aerospace engineering educational program

    NASA Technical Reports Server (NTRS)

    Craft, William; Klett, David; Lai, Steven

    1992-01-01

    The principle goal of the educational component of NASA CORE is the creation of aerospace engineering options in the mechanical engineering program at both the undergraduate and graduate levels. To accomplish this goal, a concerted effort during the past year has resulted in detailed plans for the initiation of aerospace options in both the BSME and MSME programs in the fall of 1993. All proposed new courses and the BSME aerospace option curriculum must undergo a lengthy approval process involving two cirriculum oversight committees (School of Engineering and University level) and three levels of general faculty approval. Assuming approval is obtained from all levels, the options will officially take effect in Fall '93. In anticipation of this, certain courses in the proposed curriculum are being offered during the current academic year under special topics headings so that current junior level students may graduate in May '94 under the BSME aerospace option. The proposed undergraduate aerospace option curriculum (along with the regular mechanical engineering curriculum for reference) is attached at the end of this report, and course outlines for the new courses are included in the appendix.

  20. Environmentally regulated aerospace coatings

    NASA Technical Reports Server (NTRS)

    Morris, Virginia L.

    1995-01-01

    Aerospace coatings represent a complex technology which must meet stringent performance requirements in the protection of aerospace vehicles. Topcoats and primers are used, primarily, to protect the structural elements of the air vehicle from exposure to and subsequent degradation by environmental elements. There are also many coatings which perform special functions, i.e., chafing resistance, rain erosion resistance, radiation and electric effects, fuel tank coatings, maskants, wire and fastener coatings. The scheduled promulgation of federal environmental regulations for aerospace manufacture and rework materials and processes will regulate the emissions of photochemically reactive precursors to smog and air toxics. Aerospace organizations will be required to identify, qualify and implement less polluting materials. The elimination of ozone depleting chemicals (ODC's) and implementation of pollution prevention requirements are added constraints which must be addressed concurrently. The broad categories of operations affected are the manufacture, operation, maintenance, and repair of military, commercial, general aviation, and space vehicles. The federal aerospace regulations were developed around the precept that technology had to be available to support the reduction of organic and air toxic emissions, i.e., the regulations cannot be technology forcing. In many cases, the regulations which are currently in effect in the South Coast Air Quality Management District (SCAQMD), located in Southern California, were used as the baseline for the federal regulations. This paper addresses strategies used by Southern California aerospace organizations to cope with these regulatory impacts on aerospace productions programs. All of these regulatory changes are scheduled for implementation in 1993 and 1994, with varying compliance dates established.

  1. Compression Strength of Composite Primary Structural Components

    NASA Technical Reports Server (NTRS)

    Johnson, Eric R.

    1998-01-01

    Research conducted under NASA Grant NAG-1-537 focussed on the response and failure of advanced composite material structures for application to aircraft. Both experimental and analytical methods were utilized to study the fundamental mechanics of the response and failure of selected structural components subjected to quasi-static loads. Most of the structural components studied were thin-walled elements subject to compression, such that they exhibited buckling and postbuckling responses prior to catastrophic failure. Consequently, the analyses were geometrically nonlinear. Structural components studied were dropped-ply laminated plates, stiffener crippling, pressure pillowing of orthogonally stiffened cylindrical shells, axisymmetric response of pressure domes, and the static crush of semi-circular frames. Failure of these components motivated analytical studies on an interlaminar stress postprocessor for plate and shell finite element computer codes, and global/local modeling strategies in finite element modeling. These activities are summarized in the following section. References to literature published under the grant are listed on pages 5 to 10 by a letter followed by a number under the categories of journal publications, conference publications, presentations, and reports. These references are indicated in the text by their letter and number as a superscript.

  2. Some cable suspension systems and their effects on the flexural frequencies of slender aerospace structures

    NASA Technical Reports Server (NTRS)

    Herr, R. W.

    1974-01-01

    The effects of several cable suspension configurations on the first free-free flexural frequency of uniform beams have been determined by experiment and analysis. The results of this study confirm that in general the larger the test vehicle the larger is the flexural frequency measurement error attributable to a given cable suspension configuration. For horizontally oriented beams representing modern aerospace vehicles of average size and flexibility, the restraining effects of all but the shortest support cables were minor. The restraining effects of support cables of moderate length attached near the base of vertically oriented vehicles were overshadowed by the effects of beam compression due to gravity.

  3. Aerospace Medicine

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey R.

    2006-01-01

    This abstract describes the content of a presentation for ground rounds at Mt. Sinai School of Medicine. The presentation contains three sections. The first describes the history of aerospace medicine beginning with early flights with animals. The second section of the presentation describes current programs and planning for future missions. The third section describes the medical challenges of exploration missions.

  4. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST). Progress report, 1 January-30 June 1993

    SciTech Connect

    Gangloff, R.P.; Scully, J.R.; Stoner, G.E.; Thornton, E.A.; Wawner, F.E. Jr.; Wert, J.A.

    1993-07-01

    The NASA-UVA Light Aerospace Alloy and Structures Technology (LA2ST) Program continues a high level of activity. Progress achieved between 1 Jan. and 30 Jun. 1993 is reported. The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the performance of next generation, light weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The following projects are addressed: environmental fatigue of Al-Li-Cu alloys; mechanisms of localized corrosion and environmental fracture in Al-Cu-Li-Mg-Ag alloy X2095 and compositional variations; the effect of zinc additions on the precipitation and stress corrosion cracking behavior of alloy 8090; hydrogen interactions with Al-Li-Cu alloy 2090 and model alloys; metastable pitting of aluminum alloys; cryogenic fracture toughness of Al-Cu-Li + In alloys; the fracture toughness of Weldalite (TM); elevated temperature cracking of advanced I/M aluminum alloys; response of Ti-1100/SCS-6 composites to thermal exposure; superplastic forming of Weldalite (TM); research to incorporate environmental effects into fracture mechanics fatigue life prediction codes such as NASA FLAGRO; and thermoviscoplastic behavior.

  5. Frontier Aerospace Opportunities

    NASA Technical Reports Server (NTRS)

    Bushnell, Dennis M.

    2014-01-01

    Discussion and suggested applications of the many ongoing technology opportunities for aerospace products and missions, resulting in often revolutionary capabilities. The, at this point largely unexamined, plethora of possibilities going forward, a subset of which is discussed, could literally reinvent aerospace but requires triage of many possibilities. Such initial upfront homework would lengthen the Research and Development (R&D) time frame but could greatly enhance the affordability and performance of the evolved products and capabilities. Structural nanotubes and exotic energetics along with some unique systems approaches are particularly compelling.

  6. System integration and demonstration of adhesive bonded high temperature aluminum alloys for aerospace structure, phase 2

    NASA Technical Reports Server (NTRS)

    Falcone, Anthony; Laakso, John H.

    1993-01-01

    Adhesive bonding materials and processes were evaluated for assembly of future high-temperature aluminum alloy structural components such as may be used in high-speed civil transport aircraft and space launch vehicles. A number of candidate high-temperature adhesives were selected and screening tests were conducted using single lap shear specimens. The selected adhesives were then used to bond sandwich (titanium core) test specimens, adhesive toughness test specimens, and isothermally aged lap shear specimens. Moderate-to-high lap shear strengths were obtained from bonded high-temperature aluminum and silicon carbide particulate-reinforced (SiC(sub p)) aluminum specimens. Shear strengths typically exceeded 3500 to 4000 lb/in(sup 2) and flatwise tensile strengths exceeded 750 lb/in(sup 2) even at elevated temperatures (300 F) using a bismaleimide adhesive. All faceskin-to-core bonds displayed excellent tear strength. The existing production phosphoric acid anodize surface preparation process developed at Boeing was used, and gave good performance with all of the aluminum and silicon carbide particulate-reinforced aluminum alloys investigated. The results of this program support using bonded assemblies of high-temperature aluminum components in applications where bonding is often used (e.g., secondary structures and tear stoppers).

  7. System for inspecting large size structural components

    DOEpatents

    Birks, Albert S.; Skorpik, James R.

    1990-01-01

    The present invention relates to a system for inspecting large scale structural components such as concrete walls or the like. The system includes a mobile gamma radiation source and a mobile gamma radiation detector. The source and detector are constructed and arranged for simultaneous movement along parallel paths in alignment with one another on opposite sides of a structural component being inspected. A control system provides signals which coordinate the movements of the source and detector and receives and records the radiation level data developed by the detector as a function of source and detector positions. The radiation level data is then analyzed to identify areas containing defects corresponding to unexpected variations in the radiation levels detected.

  8. Associated neural network independent component analysis structure

    NASA Astrophysics Data System (ADS)

    Kim, Keehoon; Kostrzweski, Andrew

    2006-05-01

    Detection, classification, and localization of potential security breaches in extremely high-noise environments are important for perimeter protection and threat detection both for homeland security and for military force protection. Physical Optics Corporation has developed a threat detection system to separate acoustic signatures from unknown, mixed sources embedded in extremely high-noise environments where signal-to-noise ratios (SNRs) are very low. Associated neural network structures based on independent component analysis are designed to detect/separate new acoustic sources and to provide reliability information. The structures are tested through computer simulations for each critical component, including a spontaneous detection algorithm for potential threat detection without a predefined knowledge base, a fast target separation algorithm, and nonparametric methodology for quantified confidence measure. The results show that the method discussed can separate hidden acoustic sources of SNR in 5 dB noisy environments with an accuracy of 80%.

  9. Greenstone belts: Their components and structure

    NASA Technical Reports Server (NTRS)

    Vearncombe, J. R.; Barton, J. M., Jr.; Vanreenen, D. D.; Phillips, G. N.; Wilson, A. H.

    1986-01-01

    Greenstone sucessions are defined as the nongranitoid component of granitoid-greenstone terrain and are linear to irregular in shape and where linear are termed belts. The chemical composition of greenstones is described. Also discussed are the continental environments of greenstone successions. The effects of contact with granitoids, geophysical properties, recumbent folds and late formation structures upon greenstones are examined. Large stratigraphy thicknesses are explained.

  10. Service evaluation of aircraft composite structural components

    NASA Technical Reports Server (NTRS)

    Brooks, W. A., Jr.; Dow, M. B.

    1973-01-01

    The advantages of the use of composite materials in structural applications have been identified in numerous engineering studies. Technology development programs are underway to correct known deficiencies and to provide needed improvements. However, in the final analysis, flight service programs are necessary to develop broader acceptance of, and confidence in, any new class of materials such as composites. Such flight programs, initiated by NASA Langley Research Center, are reviewed. These programs which include the selectively reinforced metal and the all-composite concepts applied to both secondary and primary aircraft structural components, are described and current status is indicated.

  11. Fracture characteristics of structural aerospace alloys containing deep surface flaws. [aluminum-titanium alloys

    NASA Technical Reports Server (NTRS)

    Masters, J. N.; Bixler, W. D.; Finger, R. W.

    1973-01-01

    Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions.

  12. Scenario-Based Specification and Evaluation of Architectures for Health Monitoring of Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Mukkamala, Ravi; Sundaram, P.

    2001-01-01

    HUMS systems have been an area of increased research in the recent times due to two main reasons: (a) increase in the occurrences of accidents in the aerospace, and (b) stricter FAA regulations on aircrafts maintenance [2]. There are several problems associated with the maintenance of aircrafts that the HUMS systems can solve through the use of several monitoring technologies.This paper documents our methodology of employing scenarios in the specification and evaluation of architecture for HUMS. Section 2 investigates related works that use scenarios in software development. Section 3 describes how we use scenarios in our work, which is followed by a demonstration of our methods in the development of KUMS in section 4. Conclusion summarizes results.

  13. Anechoic Chambers: Aerospace Applications. (Latest Citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The bibliography contains citations concerning the design, development, performance, and applications of anechoic chambers in the aerospace industry. Anechoic chamber testing equipment, techniques for evaluation of aerodynamic noise, microwave and radio antennas, and other acoustic measurement devices are considered. Shock wave studies on aircraft models and components, electromagnetic measurements, jet flow studies, and antenna radiation pattern measurements for industrial and military aerospace equipment are discussed. (Contains 50-250 citations and includes a subject term index and title list.)

  14. Anechoic Chambers: Aerospace Applications. (Latest Citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The bibliography contains citations concerning the design, development, performance, and applications of anechoic chambers in the aerospace industry. Anechoic chamber testing equipment, techniques for evaluation of aerodynamic noise, microwave and radio antennas, and other acoustic measurement devices are considered. Shock wave studies on aircraft models and components, electromagnetic measurements, jet flow studies, and antenna radiation pattern measurements for industrial and military aerospace equipment are discussed. (Contains 50-250 citations and includes a subject term index and title list.)

  15. Packaging of structural health monitoring components

    NASA Astrophysics Data System (ADS)

    Kessler, Seth S.; Spearing, S. Mark; Shi, Yong; Dunn, Christopher T.

    2004-07-01

    Structural Health Monitoring (SHM) technologies have the potential to realize economic benefits in a broad range of commercial and defense markets. Previous research conducted by Metis Design and MIT has demonstrated the ability of Lamb waves methods to provide reliable information regarding the presence, location and type of damage in composite specimens. The present NSF funded program was aimed to study manufacturing, packaging and interface concepts for critical SHM components. The intention is to be able to cheaply manufacture robust actuating/sensing devices, and isolate them from harsh operating environments including natural, mechanical, or electrical extremes. Currently the issues related to SHM system durability have remained undressed. During the course of this research several sets of test devices were fabricated and packaged to protect the piezoelectric component assemblies for robust operation. These assemblies were then tested in hot and wet conditions, as well as in electrically noisy environments. Future work will aim to package the other supporting components such as the battery and wireless chip, as well as integrating all of these components together for operation. SHM technology will enable the reduction or complete elimination of scheduled inspections, and will allow condition-based maintenance for increased reliability and reduced overall life-cycle costs.

  16. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr. (Editor)

    1995-01-01

    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  17. FDC, rapid fabrication of structural components

    SciTech Connect

    Agarwala, M.K.; Bandyopadhyay, A.; Weeren, R. van; Safari, A.; Danforth, S.C.; Langrana, N.A.; Jamalabad, V.R.; Whalen, P.J.

    1996-11-01

    Solid freeform fabrication (SFF) is used to make 3-D components directly from computer-aided design (CAD) files. Many SFF techniques have been developed to fabricate parts and prototypes from CAD without hard tooling, dies or molds. Most of these techniques have been commercialized for fabrication of polymer and plastic parts for design verification and form and fit. Other SFF techniques are being developed for production of ceramic components with functional properties. One such technique, called fused deposition of ceramics (FDC), has been developed and demonstrated for structural ceramics. FDC is based on existing fused deposition modeling (FDM{trademark}) technology, commercialized by Stratasys Inc. (Eden Prairie, Minn.), for processing of polymers and waxes. High-green-density, simple- and complex-shaped silicon nitride parts have been formed by fused deposition of ceramics.

  18. Residual thermal stress control in composite reinforced metal structures. [by mechanical loading of metal component prior to bonding

    NASA Technical Reports Server (NTRS)

    Kelly, J. B.; June, R. R.

    1972-01-01

    Advanced composite materials, composed of boron or graphite fibers and a supporting matrix, make significant structural efficiency improvements available to aircraft and aerospace designers. Residual stress induced during bonding of composite reinforcement to metal structural elements can be reduced or eliminated through suitable modification to the manufacturing processes. The most successful method employed during this program used a steel tool capable of mechanically loading the metal component in compression prior to the adhesive bonding cycle. Compression loading combined with heating to 350 F during the bond cycle can result in creep deformation in aluminum components. The magnitude of the deformation increases with increasing stress level during exposure to 350 F.

  19. Ultrasonic Characterization of Aerospace Composites

    NASA Technical Reports Server (NTRS)

    Leckey, Cara; Johnston, Patrick; Haldren, Harold; Perey, Daniel

    2015-01-01

    Composite materials have seen an increased use in aerospace in recent years and it is expected that this trend will continue due to the benefits of reduced weight, increased strength, and other factors. Ongoing work at NASA involves the investigation of the large-scale use of composites for spacecraft structures (SLS components, Orion Composite Crew Module, etc). NASA is also involved in work to enable the use of composites in advanced aircraft structures through the Advanced Composites Project (ACP). In both areas (space and aeronautics) there is a need for new nondestructive evaluation and materials characterization techniques that are appropriate for characterizing composite materials. This paper will present an overview of NASA's needs for characterizing aerospace composites, including a description of planned and ongoing work under ACP for the detection of composite defects such as fiber waviness, reduced bond strength, delamination damage, and microcracking. The research approaches include investigation of angle array, guided wave, and phase sensitive ultrasonic methods. The use of ultrasonic simulation tools for optimizing and developing methods will also be discussed.

  20. Low-order design and high-order simulation of active closed-loop control for aerospace structures under construction

    NASA Technical Reports Server (NTRS)

    Balas, Mark J.

    1989-01-01

    Partially constructed/assembled structures in space are complicated enough but their dynamics will also be operating in closed-loop with feedback controllers. The dynamics of such structures are modeled by large-scale finite element models. The model dimension L is extremely large (approximately 10,000) while the numbers of actuators (M) and sensors (P) are small. The model parameters M(sub m) mass matrix, D(sub o) damping matrix, and K(sub o) stiffness matrix, are all symmetric and sparse (banded). Thus simulation of open-loop structure models of very large dimension can be accomplished by special integration techniques for sparse matrices. The problem of simulation of closed-loop control of such structures is complicated by the addition of controllers. Simulation of closed-loop controlled structures is an essential part of the controller design and evaluation process. Current research in the following areas is presented: high-order simulation of actively controlled aerospace structures; low-order controller design and SCI compensation for unmodeled dynamics; prediction of closed-loop stability using asymptotic eigenvalue series; and flexible robot manipulator control experiment.

  1. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST). Research on Materials for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Starke, Edgar A., Jr.; Kelly, Robert G.; Scully, John R.; Stoner, Glenn E.; Wert, John A.

    1997-01-01

    Since 1986, the NASA-Langley Research Center has sponsored the NASA-UVa Light Alloy and Structures Technology (LA2ST) Program at the University of Virginia (UVa). The fundamental objective of the LA2ST program is to conduct interdisciplinary graduate student research on the performance of next generation, light-weight aerospace alloys, composites and thermal gradient structures. The LA2ST program has aimed to product relevant data and basic understanding of material mechanical response, environmental/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; measurement and modeling advances; and a pool of educated graduate students for aerospace technologies. The scope of the LA2ST Program is broad. Research areas include: (1) Mechanical and Environmental Degradation Mechanisms in Advanced Light Metals and Composites, (2) Aerospace Materials Science, (3) Mechanics of materials for Aerospace Structures, and (4) Thermal Gradient Structures. A substantial series of semi-annual progress reports issued since 1987 documents the technical objectives, experimental or analytical procedures, and detailed results of graduate student research in these topical areas.

  2. Aerospace gerontology

    NASA Technical Reports Server (NTRS)

    Comfort, A.

    1982-01-01

    The relevancy of gerontology and geriatrics to the discipline of aerospace medicine is examined. It is noted that since the shuttle program gives the facility to fly passengers, including specially qualified older persons, it is essential to examine response to acceleration, weightlessness, and re-entry over the whole adult lifespan, not only its second quartile. The physiological responses of the older person to weightlessness and the return to Earth gravity are reviewed. The importance of the use of the weightless environment to solve critical problems in the fields of fundamental gerontology and geriatrics is also stressed.

  3. Adhesives for Aerospace

    NASA Technical Reports Server (NTRS)

    Meade, L. E.

    1985-01-01

    The industry is hereby challenged to integrate adhesive technology with the total structure requirements in light of today's drive into automation/mechanization. The state of the art of adhesive technology is fairly well meeting the needs of the structural designers, the processing engineer, and the inspector, each on an individual basis. The total integration of these needs into the factory of the future is the next collective hurdle to be achieved. Improved processing parameters to fit the needs of automation/mechanization will necessitate some changes in the adhesive forms, formulations, and chemistries. Adhesives have, for the most part, kept up with the needs of the aerospace industry, normally leading the rest of the industry in developments. The wants of the aerospace industry still present a challenge to encompass all elements, achieving a totally integrated joined and sealed structural system. Better toughness with hot-wet strength improvements is desired. Lower cure temperatures, longer out times, and improved corrosion inhibition are desired.

  4. Basic Aerospace Education Library

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1975

    1975-01-01

    Lists the most significant resource items on aerospace education which are presently available. Includes source books, bibliographies, directories, encyclopedias, dictionaries, audiovisuals, curriculum/planning guides, aerospace statistics, aerospace education statistics and newsletters. (BR)

  5. Aerospace Education - An Overview

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1975

    1975-01-01

    Discusses the surge of interest throughout the country in aerospace education and discusses what aerospace education is, the implications in career education and the relevance of aerospace education in the curriculum. (BR)

  6. Mass spectrometry of aerospace materials

    NASA Technical Reports Server (NTRS)

    Colony, J. A.

    1976-01-01

    Mass spectrometry is used for chemical analysis of aerospace materials and contaminants. Years of analytical aerospace experience have resulted in the development of specialized techniques of sampling and analysis which are required in order to optimize results. This work has resulted in the evolution of a hybrid method of indexing mass spectra which include both the largest peaks and the structurally significant peaks in a concise format. With this system, a library of mass spectra of aerospace materials was assembled, including the materials responsible for 80 to 90 percent of the contamination problems at Goddard Space Flight Center during the past several years.

  7. Effective safety measures with tests followed by design correction for aerospace structures

    NASA Astrophysics Data System (ADS)

    Matsumura, Taiki

    Analytical and computational prediction tools enable us to design aircraft and spacecraft components with high degree of confidence. While the accuracy of such predictions has been improved over the years, uncertainty continues to be added by new materials and new technology introduced in order to improve performance. This requires us to have reality checks, such as tests, in order to make sure that the prediction tools are reliable enough to ensure safety. While tests can reveal unsafe designs and lead to design correction, these tests are very costly. Therefore, it is important to manage such a design-test-correction cycle effectively. In this dissertation, we consider three important test stages in the lifecycle of an aviation system. First, we dealt with characterization tests that reveal failure modes of new materials or new geometrical arrangements. We investigated the challenge associated with getting the best characterization with a limited number of tests. We have found that replicating tests to attenuate the effect of noise in observation is not necessary because some surrogate models can serve as a noise filter without having replicated data. Instead, we should focus on exploring the design space with different structural configurations in order to discover unknown failure modes. Next, we examined post-design tests for design acceptance followed by possible redesign. We looked at the question of how to balance the desire for better performance achieved by redesign against the cost of redesign. We proposed a design optimization framework that provides tradeoff information between the expected performance improvement by redesign and the probability of redesign, equivalent to the cost of redesign. We also demonstrated that the proposed method can reduce the performance loss due to a conservative reliability estimate. The ultimate test, finally, is whether the structures do not fail in flight. Once an accident occurs, an accident investigation takes place

  8. NASA's activities in the conservation of strategic aerospace materials

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1980-01-01

    The United States imports 50-100 percent of certain metals critical to the aerospace industry, namely, cobalt, columbium, chromium, and tantalum. In an effort to reduce this dependence on foreign sources, NASA is planning a program called Conservation of Strategic Aerospace Materials (COSAM), which will provide technology minimizing strategic metal content in the components of aerospace structures such as aircraft engines. With a proposed starting date of October 1981, the program will consist of strategic element substitution, process technology development, and alternate materials research. NASA's two-fold pre-COSAM studies center on, first, substitution research involving nickel-base and cobalt-base superalloys (Waspaloy, Udimet-700, MAE-M247, Rene 150, HA-188) used in turbine disks, low-pressure blades, turbine blades, and combustors; and, second, alternate materials research devoted initially to investigating possible structural applications of the intermetallic alloys nickel aluminide and iron aluminide.

  9. The Aerospace Age. Aerospace Education I.

    ERIC Educational Resources Information Center

    Smith, J. C.

    This book is written for use only in the Air Force ROTC program and cannot be purchased on the open market. The book describes the historical development of aerospace industry. The first chapter contains a brief review of the aerospace environment and the nature of technological changes brought by the aerospace revolution. The following chapter…

  10. Nondestructive Evaluation for Aerospace Composites

    NASA Technical Reports Server (NTRS)

    Leckey, Cara; Cramer, Elliott; Perey, Daniel

    2015-01-01

    Nondestructive evaluation (NDE) techniques are important for enabling NASA's missions in space exploration and aeronautics. The expanded and continued use of composite materials for aerospace components and vehicles leads to a need for advanced NDE techniques capable of quantitatively characterizing damage in composites. Quantitative damage detection techniques help to ensure safety, reliability and durability of space and aeronautic vehicles. This presentation will give a broad outline of NASA's range of technical work and an overview of the NDE research performed in the Nondestructive Evaluation Sciences Branch at NASA Langley Research Center. The presentation will focus on ongoing research in the development of NDE techniques for composite materials and structures, including development of automated data processing tools to turn NDE data into quantitative location and sizing results. Composites focused NDE research in the areas of ultrasonics, thermography, X-ray computed tomography, and NDE modeling will be discussed.

  11. Thermal oxidation induced degradation of carbon fiber reinforced composites and carbon nanotube sheet enhanced fiber/matrix interface for high temperature aerospace structural applications

    NASA Astrophysics Data System (ADS)

    Haque, Mohammad Hamidul

    Recent increase in the use of carbon fiber reinforced polymer matrix composite, especially for high temperature applications in aerospace primary and secondary structures along with wind energy and automotive industries, have generated new challenges to predict its failure mechanisms and service life. This dissertation reports the experimental study of a unidirectional carbon fiber reinforced bismaleimide (BMI) composites (CFRC), an excellent candidate for high temperature aerospace components, undergoing thermal oxidation at 260 °C in air for over 3000 hours. The key focus of the work is to investigate the mechanical properties of the carbon fiber BMI composite subjected to thermal aging in three key aspects - first, studying its bulk flexural properties (in macro scale), second, characterizing the crack propagation along the fiber direction, representing the interfacial bonding strength between fiber and matrix (in micro scale), and third, introducing nano-structured materials to modify the interface (in nano scale) between the carbon fiber and BMI resin and mechanical characterization to study its influence on mitigating the aging effect. Under the first category, weight loss and flexural properties have been monitored as the oxidation propagates through the fiber/matrix interface. Dynamic mechanical analysis and micro-computed tomography analysis have been performed to analyze the aging effects. In the second category, the long-term effects of thermal oxidation on the delamination (between the composite plies) and debonding (between fiber and matrix) type fracture toughness have been characterized by preparing two distinct types of double cantilever beam specimens. Digital image correlation has been used to determine the deformation field and strain distribution around the crack propagation path. Finally the resin system and the fiber/matrix interface have been modified using nanomaterials to mitigate the degradations caused by oxidation. Nanoclay modified

  12. On-board energy management for high-speed aerospace vehicles: System and component-level energy-based optimization and analysis

    NASA Astrophysics Data System (ADS)

    Taylor, Trent Matthew

    This dissertation addresses in detail three main topics for advancing the state-of-the-art in hypersonic aerospace systems: (1) the development of a synergistic method based on entropy generation in order to analyze, evaluate, and optimize vehicle performance, (2) the development and analysis of innovative unconventional flow-control methods for increasing vehicle performance utilizing entropy generation as a fundamental descriptor and predictor of performance, and (3) an investigation of issues arising when evaluating (predicting) actual flight vehicle performance using ground test facilities. Vehicle performance is analyzed beginning from fundamental considerations involving fluid and thermodynamic balance relationships. The results enable the use of entropy generation as the true "common currency" (single loss parameter) for systematic and consistent evaluation of performance losses across the vehicle as an integrated system. Innovative flow control methods are modeled using state of the art CFD codes in which the flow is energized in targeted local zones with emphasis on shock wave modification. Substantial drag reductions are observed such that drag can decrease to 25% of the baseline. Full vehicle studies are then conducted by comparing traditional and flow-controlled designs and very similar axial force is found with an accompanying increase in lift for the flow-control design to account for on-board energy-addition components. Finally, a full engine flowpath configuration is designed for computational studies of ground test performance versus actual flight performance with emphasis on understanding the effect of ground-based vitiate (test contaminant). It is observed that the presence of vitiate in the test medium can also have a significant first-order effect on ignition delay as well as the thermodynamic response to a given heat release in the fuel.

  13. Aerothermal and aeroelastic response prediction of aerospace structures in high-speed flows using direct numerical simulation

    NASA Astrophysics Data System (ADS)

    Ostoich, Christopher Mark

    Future high-speed air vehicles will be lightweight, flexible, and reusable. Ve- hicles fitting this description are subject to severe thermal and fluid dynamic loading from multiple sources such as aerothermal heating, propulsion sys- tem exhaust, and high dynamic pressures. The combination of low-margin design requirements and extreme environmental conditions emphasizes the occurrence of fluid-thermal-structural coupling. Numerous attempts to field such vehicles have been unsuccessful over the past half-century due par- tially to the inability of traditional design and analysis practices to predict the structural response in this flight regime. In this thesis, a high-fidelity computational approach is used to examine the fluid-structural response of aerospace structures in high-speed flows. The method is applied to two cases: one involving a fluid-thermal interaction problem in a hypersonic flow and the other a fluid-structure interaction study involving a turbulent boundary layer and a compliant panel. The coupled fluid-thermal investigation features a nominally rigid alu- minum spherical dome fixed to a ceramic panel holder placed in a Mach 6.59 laminar boundary layer. The problem was originally studied by Glass and Hunt in a 1988 wind tunnel experiment in the NASA Langley 8-Foot High Temperature Tunnel and is motivated by thermally bowed body panels designed for the National Aerospace Plane. In this work, the compressible Navier-Stokes equations for a thermally perfect gas and the transient heat equation in the structure are solved simultaneously using two high-fidelity solvers coupled at the solid-fluid interface. Predicted surface heat fluxes are within 10% of the measured values in the dome interior with greater differ- ences found near the dome edges where uncertainties concerning the exper- imental model's construction likely influence the thermal dynamics. On the flat panel holder, the local surface heat fluxes approach those on the wind- ward dome face

  14. Materials for aerospace

    SciTech Connect

    Steinberg, M.A.

    1986-10-01

    Early last year the US Office of Science and Technology put forward an agenda for American aerospace activity in the coming decades. The plan established goals for subsonic, supersonic and transatmospheric hypersonic flight. Those goals, together with Reagan Administration's programs for a space station and the Strategic Defense Initiative, serve as a driving force for extensive improvements in the materials that enable airplanes and spacecraft to function efficiently. The development of materials, together with advances in the technology of fabricating parts, will play a key role in aerospace systems of the future. Among the materials developments projected for the year 2000 are new composites and alloys for structural members; superalloys, ceramics and glass composites for propulsion systems, and carbon-carbon composites (carbon fibers in a carbon matrix) for high-temperature applications in places where resistance to heat and ablation is critical. 5 figures.

  15. Software for Testing Electroactive Structural Components

    NASA Technical Reports Server (NTRS)

    Moses, Robert W.; Fox, Robert L.; Dimery, Archie D.; Bryant, Robert G.; Shams, Qamar

    2003-01-01

    A computer program generates a graphical user interface that, in combination with its other features, facilitates the acquisition and preprocessing of experimental data on the strain response, hysteresis, and power consumption of a multilayer composite-material structural component containing one or more built-in sensor(s) and/or actuator(s) based on piezoelectric materials. This program runs in conjunction with Lab-VIEW software in a computer-controlled instrumentation system. For a test, a specimen is instrumented with appliedvoltage and current sensors and with strain gauges. Once the computational connection to the test setup has been made via the LabVIEW software, this program causes the test instrumentation to step through specified configurations. If the user is satisfied with the test results as displayed by the software, the user activates an icon on a front-panel display, causing the raw current, voltage, and strain data to be digitized and saved. The data are also put into a spreadsheet and can be plotted on a graph. Graphical displays are saved in an image file for future reference. The program also computes and displays the power and the phase angle between voltage and current.

  16. Nondestructive characterization of structural ceramic components

    SciTech Connect

    Ellingson, W.A.; Steckenrider, J.S.; Sivers, E.A.; Ling, J.R.

    1994-06-01

    Advanced structural ceramic components under development for heat-engine applications include both monolithic and continuous fiber composites (CFC). Nondestructive characterization (NDC) methods being developed differ for each material system. For monolithic materials, characterization during processing steps is important. For many CFC, only post process characterization is possible. Many different NDC systems have been designed and built A 3D x-ray micro computed tomographic (3DXCT) imaging system has been shown to be able to map density variations to better than 3% in pressure slip cast Si{sub 3}N{sub 4} monolithic materials. In addition, 3DXCT coupled to image processing has been shown to be able to map through-thickness fiber orientations in 2D lay-ups of 0{degrees}/45{degrees}, 0{degrees}/75{degrees}, 0{degrees}/90{degrees}, in SiC/SiC CVI CFC. Fourier optics based laser scatter systems have been shown to be able to detect surface and subsurface defects (as well as microstructural variations) in monolithic Si{sub 3}N{sub 4} bearing balls. Infrared methods using photothermal excitation have been shown to be able to detect and measure thermal diffusivity differences on SiC/SiC 2D laminated CFC which have been subjected to different thermal treatments including thermal shock and oxidizing environments. These NDC methods and their applications help provide information to allow reliable usage of ceramics in advanced heat engine applications.

  17. Structural weights analysis of advanced aerospace vehicles using finite element analysis

    NASA Technical Reports Server (NTRS)

    Bush, Lance B.; Lentz, Christopher A.; Rehder, John J.; Naftel, J. Chris; Cerro, Jeffrey A.

    1989-01-01

    A conceptual/preliminary level structural design system has been developed for structural integrity analysis and weight estimation of advanced space transportation vehicles. The system includes a three-dimensional interactive geometry modeler, a finite element pre- and post-processor, a finite element analyzer, and a structural sizing program. Inputs to the system include the geometry, surface temperature, material constants, construction methods, and aerodynamic and inertial loads. The results are a sized vehicle structure capable of withstanding the static loads incurred during assembly, transportation, operations, and missions, and a corresponding structural weight. An analysis of the Space Shuttle external tank is included in this paper as a validation and benchmark case of the system.

  18. Optical Information Processing for Aerospace Applications 2

    NASA Technical Reports Server (NTRS)

    Stermer, R. L. (Compiler)

    1984-01-01

    Current research in optical processing, and determination of its role in future aerospace systems was reviewed. It is shown that optical processing offers significant potential for aircraft and spacecraft control, pattern recognition, and robotics. It is demonstrated that the development of optical devices and components can be implemented in practical aerospace configurations.

  19. NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-based materials for high speed aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr.

    1993-01-01

    This report on the NASA-UVa Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from January 1, 1992 to June 30, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) powder metallurgy 2XXX alloys, (3) rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  20. Applications of integrated design/analysis systems in aerospace structural design

    NASA Technical Reports Server (NTRS)

    Mason, Philip; Lerner, Edwin; Sobel, Lawrence

    1989-01-01

    Integrated structural analysis and design systems and structural optimization procedures are being used in a production environment. Successful use of these systems requires experienced personnel. Interactive computer graphics can and will play a significant role in the analysis, optimization, design and manufacturing areas. Practical structural optimization procedures are tools that must be made available to the team. Much work still needs to be done to tie finite-element modeling to actual design details which are being tracked on systems such as CADAM or CATIA. More work needs to be done to automate the detailed design and analysis process. More emphasis should be placed on the real design problems.

  1. Hardware Specific Integration Strategy for Impedance-Based Structural Health Monitoring of Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Owen, Robert B.; Gyekenyesi, Andrew L.; Inman, Daniel J.; Ha, Dong S.

    2011-01-01

    The Integrated Vehicle Health Management (IVHM) Project, sponsored by NASA's Aeronautics Research Mission Directorate, is conducting research to advance the state of highly integrated and complex flight-critical health management technologies and systems. An effective IVHM system requires Structural Health Monitoring (SHM). The impedance method is one such SHM technique for detection and monitoring complex structures for damage. This position paper on the impedance method presents the current state of the art, future directions, applications and possible flight test demonstrations.

  2. Molecular dynamics modelling of mechanical properties of polymers for adaptive aerospace structures

    NASA Astrophysics Data System (ADS)

    Papanikolaou, Michail; Drikakis, Dimitris; Asproulis, Nikolaos

    2015-02-01

    The features of adaptive structures depend on the properties of the supporting materials. For example, morphing wing structures require wing skin materials, such as rubbers that can withstand the forces imposed by the internal mechanism while maintaining the required aerodynamic properties of the aircraft. In this study, Molecular Dynamics and Minimization simulations are being used to establish well-equilibrated models of Ethylene-Propylene-Diene Monomer (EPDM) elastomer systems and investigate their mechanical properties.

  3. Advanced Ceramic Materials for Future Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Misra, Ajay

    2015-01-01

    With growing trend toward higher temperature capabilities, lightweight, and multifunctionality, significant advances in ceramic matrix composites (CMCs) will be required for future aerospace applications. The presentation will provide an overview of material requirements for future aerospace missions, and the role of ceramics and CMCs in meeting those requirements. Aerospace applications will include gas turbine engines, aircraft structure, hypersonic and access to space vehicles, space power and propulsion, and space communication.

  4. Analysis and Sizing for Transient Thermal Heating of Insulated Aerospace Vehicle Structures

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.

    2012-01-01

    An analytical solution was derived for the transient response of an insulated structure subjected to a simplified heat pulse. The solution is solely a function of two nondimensional parameters. Simpler functions of these two parameters were developed to approximate the maximum structural temperature over a wide range of parameter values. Techniques were developed to choose constant, effective thermal properties to represent the relevant temperature and pressure-dependent properties for the insulator and structure. A technique was also developed to map a time-varying surface temperature history to an equivalent square heat pulse. Equations were also developed for the minimum mass required to maintain the inner, unheated surface below a specified temperature. In the course of the derivation, two figures of merit were identified. Required insulation masses calculated using the approximate equation were shown to typically agree with finite element results within 10%-20% over the relevant range of parameters studied.

  5. The use of subjective expert opinions in cost optimum design of aerospace structures. [probabilistic failure models

    NASA Technical Reports Server (NTRS)

    Thomas, J. M.; Hanagud, S.

    1975-01-01

    The results of two questionnaires sent to engineering experts are statistically analyzed and compared with objective data from Saturn V design and testing. Engineers were asked how likely it was for structural failure to occur at load increments above and below analysts' stress limit predictions. They were requested to estimate the relative probabilities of different failure causes, and of failure at each load increment given a specific cause. Three mathematical models are constructed based on the experts' assessment of causes. The experts' overall assessment of prediction strength fits the Saturn V data better than the models do, but a model test option (T-3) based on the overall assessment gives more design change likelihood to overstrength structures than does an older standard test option. T-3 compares unfavorably with the standard option in a cost optimum structural design problem. The report reflects a need for subjective data when objective data are unavailable.

  6. Large-Deformation Displacement Transfer Functions for Shape Predictions of Highly Flexible Slender Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Fleischer, Van Tran

    2013-01-01

    Large deformation displacement transfer functions were formulated for deformed shape predictions of highly flexible slender structures like aircraft wings. In the formulation, the embedded beam (depth wise cross section of structure along the surface strain sensing line) was first evenly discretized into multiple small domains, with surface strain sensing stations located at the domain junctures. Thus, the surface strain (bending strains) variation within each domain could be expressed with linear of nonlinear function. Such piecewise approach enabled piecewise integrations of the embedded beam curvature equations [classical (Eulerian), physical (Lagrangian), and shifted curvature equations] to yield closed form slope and deflection equations in recursive forms.

  7. Mass Efficiency Considerations for Thermally Insulated Structural Skin of an Aerospace Vehicle

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.

    2012-01-01

    An approximate equation was derived to predict the mass of insulation required to limit the maximum temperature reached by an insulated structure subjected to a transient heating pulse. In the course of the derivation two figures of merit were identified. One figure of merit correlates to the effectiveness of the heat capacity of the underlying structural material in reducing the amount of required insulation. The second figure of merit provides an indicator of the mass efficiency of the insulator material. An iterative, one dimensional finite element analysis was used to size the external insulation required to protect the structure at a single location on the Space Shuttle Orbiter and a reusable launch vehicle. Required insulation masses were calculated for a range of different materials for both structure and insulator. The required insulation masses calculated using the approximate equation were shown to typically agree with finite element results within 10 to 20 percent over the range of parameters studied. Finite element results closely followed the trends indicated by both figures of merit.

  8. The Development of Materials for Structures and Radiation Shielding in Aerospace

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.; Orwoll, Robert A.

    2001-01-01

    Polymeric materials on space vehicles and high-altitude aircraft win be exposed to highly penetrating radiations. These radiations come from solar flares and galactic cosmic rays (GCR). Radiation from solar flares consists primarily of protons with energies less than 1 GeV. On the other hand, GCR consist of nuclei with energies as high as 10(exp 10) GeV. Over 90% of the nuclei in GCR are protons and alpha particles, however there is a small but significant component of particles with atomic numbers greater than ten. Particles with high atomic number (Z) and high energy interact with very high specific ionization and thus represent a serious hazard for humans and electronic equipment on a spacecraft or on high-altitude commercial aircraft (most importantly for crew members who would have long exposures). Neutrons generated by reactions with the high energy particles also represent a hazard both for humans and electronic equipment.

  9. On-line failure detection and damping measurement of aerospace structures by random decrement signatures

    NASA Technical Reports Server (NTRS)

    Cole, H. A., Jr.

    1973-01-01

    Random decrement signatures of structures vibrating in a random environment are studied through use of computer-generated and experimental data. Statistical properties obtained indicate that these signatures are stable in form and scale and hence, should have wide application in one-line failure detection and damping measurement. On-line procedures are described and equations for estimating record-length requirements to obtain signatures of a prescribed precision are given.

  10. 41st Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Editor)

    2012-01-01

    The proceedings of the 41st Aerospace Mechanisms Symposium are reported. JPL hosted the conference, which was held in Pasadena Hilton, Pasadena, California on May 16-18, 2012. Lockheed Martin Space Systems cosponsored the symposium. Technology areas covered include gimbals and positioning mechanisms, components such as hinges and motors, CubeSats, tribology, and Mars Science Laboratory mechanisms.

  11. Applications of laser ultrasound NDT methods on composite structures in aerospace industry

    NASA Astrophysics Data System (ADS)

    Kalms, Michael; Focke, Oliver; v. Kopylow, Christoph

    2008-09-01

    Composite materials are used more and more in aircraft production. Main composite types are Carbon Fiber Reinforced Plastics (CFRP), Glass Fiber Reinforced Plastics (GFRP) and metal-aluminium laminates (e. g. Glass Fiber Aluminium Reinforced GLARE©). Typical parts made of CFRP material are flaps, vertical and horizontal tail planes, center wing boxes, rear pressure bulkheads, ribs and stringers. These composite parts require adequate nondestructive testing (NDT) methods. Flaws to be detected are delaminations and debondings, porosity and foreign body inclusion. Manual ultrasonic testing with single element transducers is still the most applied method for composite parts with small and medium size. The extension of the conventional ultrasound technique for nondestructive testing with the laser ultrasound method brings new possibilities into the production processes for example the inspection of complex CFRP-components and the possibilities of online observation under remote control. In this paper we describe the principle of laser ultrasound with respect to the demands of nondestructive testing especially of small complex CFRP and C/PPS parts. We report applications of laser-based ultrasound options with generated types of guided and bulk waves on modern aircraft materials.

  12. Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures

    NASA Astrophysics Data System (ADS)

    Guzman, E.; Cugnoni, J.; Gmür, T.; Bonhôte, P.; Schorderet, A.

    2013-06-01

    This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors’ survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures.

  13. Advances in the analysis and design of adhesive-bonded joints in composite aerospace structures

    NASA Technical Reports Server (NTRS)

    Hart-Smith, L. J.

    1974-01-01

    Several aspects of adhesive-bonded joint analysis and design are presented from the reference of size of structure or load intensity. This integrates the individual characterizations of double-lap, single-lap, stepped-lap, tapered-lap and scarf joints. The paper includes an overview of bonded joint selection from the standpoints of design, fabrication, and processing, each bearing in mind the influence of such considerations on the strength of the joint. A case study is presented of the optimization of a specific relatively thick titanium-to-graphite epoxy stepped-lap joint, using the digital computer analysis program A4EG. The factors accounted for are adhesive plasticity, adherend stiffness imbalance, adherend thermal mismatch, and change of material properties within the range of temperature environment and with load direction. The strength increases obtainable by refining the initial design are demonstrated.

  14. Ultrasonic guided wave monitoring of composite wing skin-to-spar bonded joints in aerospace structures

    NASA Astrophysics Data System (ADS)

    Matt, Howard; Bartoli, Ivan; Lanza di Scalea, Francesco

    2005-10-01

    The monitoring of adhesively bonded joints by ultrasonic guided waves is the general topic of this paper. Specifically, composite-to-composite joints representative of the wing skin-to-spar bonds of unmanned aerial vehicles (UAVs) are examined. This research is the first step towards the development of an on-board structural health monitoring system for UAV wings based on integrated ultrasonic sensors. The study investigates two different lay-ups for the wing skin and two different types of bond defects, namely poorly cured adhesive and disbonded interfaces. The assessment of bond state is based on monitoring the strength of transmission through the joints of selected guided modes. The wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by ultrasonic testing that uses small PZT disks preferably exciting and detecting the single-plate s0 mode. Both the models and the experiments confirm that the ultrasonic energy transmission through the joint is highly dependent on the bond conditions, with defected bonds resulting in increased transmission strength. Large sensitivity to the bond conditions is found at mode coupling points, as a result of the large interlayer energy transfer.

  15. Estimators for variance components in structured stair nesting models

    NASA Astrophysics Data System (ADS)

    Monteiro, Sandra; Fonseca, Miguel; Carvalho, Francisco

    2016-06-01

    The purpose of this paper is to present the estimation of the components of variance in structured stair nesting models. The relationship between the canonical variance components and the original ones, will be very important in obtaining that estimators.

  16. The 11th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Various mechanisms in aerospace engineering were presented at this conference. Specifications, design, and use of spacecraft and missile components are discussed, such as tail assemblies, radiometers, magnetormeters, pins, reaction wheels, ball bearings, actuators, mirrors, nutation dampers, airfoils, solar arrays, etc.

  17. Novel Nanolaminates for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Volz, Martin; Mazuruk, consty

    2006-01-01

    Nanolaminate manufacturing (NLM) is a new way of developing materials whose properties can far exceed those of homogeneous materials. Traditional alloys, composites and bulk laminates tend to average the properties of the materials from which they were made. With nanostructured materials, the high density of interfaces between dissimilar materials results in novel material properties. For example, materials made -from alternating nanoscale layers of metals and oxides have exhibited thermal conductivities far below those of the oxides themselves. Also, metallic nanolaminates can have peak strengths 100 times lager than the bulk constituent metals. Recent work at MSFC has focused on the development of nickel/aluminum oxide (Ni/Al2O3)) nanolaminates. Ni/Al2O3 nanolaminates are expected to have better strength, creep and fatigue resistance, oxygen compatibility, and corrosion resistance than the traditional metal-matrix composites of this material, which has been used in a variety of aerospace applications. A chemical vapor deposition (CW) system has been developed and optimized for the deposition of nanolaminates. Nanolaminates with layer thicknesses between 10 and 300 nm have been successfully grown and characterization has included scanning electron microscopy (SEM) and atomic force microscopy (AFM) Nanolaminates have a large variety of potential applications. They can be tailored to have both very small and anisotropic thermal conductivities and are promising as thermal coatings for both rock$ engine components and aerobraking structures. They also have the potential to be used in aerospace applications where strength at high temperatures, corrosion resistance or resistance to hydrogen embrittlement is important. Both CVD and magnetron sputtering facilities are available for the deposition of nanolayered materials. Characterization equipment includes SEM, AFM, X-ray diffraction, transmission electron microscopy, optical profilometry, and mechanical tensile pull

  18. An Aerospace Workshop

    ERIC Educational Resources Information Center

    Hill, Bill

    1972-01-01

    Describes the 16-day, 10,000 mile national tour of the nation's major aerospace research and development centers by 65 students enrolled in Central Washington State College's Summer Aerospace Workshop. (Author/MB)

  19. Application of component mode synthesis in structural dynamics

    NASA Technical Reports Server (NTRS)

    Craig, R. R.

    1986-01-01

    The principal analytical techniques used for component mode synthesis (CMS) of undamped systems and their application to structural dynamics are discussed. In the CMS, a system is divided into components or substructures, and for each of these components, the number of degrees of freedom is reduced by expressing the physical coordinates in terms of a reduced set of component modal coordinates. Among a number of component modes, a new form of component mode, called an applied force attachment mode, is described. Consideration is given to literature studies of damped structures and recent combined analytical/experimental studies.

  20. Structural components and architectures of RNA exosomes.

    PubMed

    Januszyk, Kurt; Lima, Christopher D

    2010-01-01

    A large body of structural work conducted over the past ten years has elucidated mechanistic details related to 3' to 5' processing and decay of RNA substrates by the RNA exosome. This chapter will focus on the structural organization of eukaryotic exosomes and their evolutionary cousins in bacteria and archaea with an emphasis on mechanistic details related to substrate recognition and to 3' to 5' phosphorolytic exoribonucleolytic activities of bacterial and archaeal exosomes as well as the hydrolytic exoribonucleolytic and endoribonucleolytic activities of eukaryotic exosomes. These points will be addressed in large part through presentation of crystal structures ofphosphorolytic enzymes such as bacterial RNase PH, PNPase and archaeal exosomes and crystal structures ofthe eukaryotic exosome and exosome sub-complexes in addition to standalone structures of proteins that catalyze activities associated with the eukaryotic RNA exosome, namely Rrp44, Rrp6 and their bacterial counterparts. PMID:21618871

  1. The 26th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The proceedings of the 26th Aerospace Mechanisms Symposium, which was held at the Goddard Space Flight Center on May 13, 14, and 15, 1992 are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, latches, connectors and other mechanisms for large space structures.

  2. The 27th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Mancini, Ron (Compiler)

    1993-01-01

    The proceedings of the 27th Aerospace Mechanisms Symposium, which was held at ARC, Moffett Field, California, on 12-14 May 1993, are reported. Technological areas covered include the following: actuators, aerospace mechanism applications for ground support equipment, lubricants, latches, connectors, robotic mechanisms, and other mechanisms for large space structures.

  3. NASA-UVA Light Aerospace Alloy and Structures Technology program (LA2ST). Progress report, 1 January 1995-30 June 1995

    SciTech Connect

    Starke, E.A. Jr.; Gangloff, R.P.; Herakovich, C.T.; Scully, J.R.; Shiflet, G.J.; Stoner, G.E.; Wert, J.A.

    1995-07-01

    The objective of the LA2ST Program is to conduct interdisciplinary graduate student research on the= performance of next generation, light-weight aerospace alloys, composites, and thermal gradient structures in collaboration with NASA-Langley researchers. The general aim is to produce relevant data and basic understanding of material mechanical response, environment/corrosion behavior, and microstructure; new monolithic and composite alloys; advanced processing methods; new solid and fluid mechanics analyses; measurement and modeling advances; and a pool of educated students for aerospace technologies. Specific technical objectives are presented for each of the following research projects: time-temperature dependent fracture in advanced wrought ingot metallurgy, and spray deposited aluminum alloys; cryogenic temperature effects on the deformation and fracture of Al-Li-Cu-In alloys; effects of aging and temperature on the ductile fracture of AA2095 and AA2195; mechanisms of localized corrosion in alloys 2090 and 2095; hydrogen interactions in aluminum-lithium alloys 2090 and selected model alloys; mechanisms of deformation and fracture in high strength titanium alloys (effects of temperature and hydrogen and effects of temperature and microstructure); evaluations of wide-panel aluminum alloy extrusions; Al-Si-Ge alloy development; effects of texture and precipitates on mechanical property anisotropy of Al-Cu-Mg-X alloys; damage evolution in polymeric composites; and environmental effects in fatigue life prediction - modeling crack propagation in light aerospace alloys.

  4. Key Issues for Aerospace Applications of Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Clinton, R. G., Jr.; Levine, S. R.

    1998-01-01

    Ceramic matrix composites (CMC) offer significant advantages for future aerospace applications including turbine engine and liquid rocket engine components, thermal protection systems, and "hot structures". Key characteristics which establish ceramic matrix composites as attractive and often enabling choices are strength retention at high temperatures and reduced weight relative to currently used metallics. However, due to the immaturity of this class of materials which is further compounded by the lack of experience with CMC's in the aerospace industry, there are significant challenges involved in the development and implementation of ceramic matrix composites into aerospace systems. Some of the more critical challenges are attachment and load transfer methodologies; manufacturing techniques, particularly scale up to large and thick section components; operational environment resistance; damage tolerance; durability; repair techniques; reproducibility; database availability; and the lack of validated design and analysis tools. The presentation will examine the technical issues confronting the application of ceramic matrix composites to aerospace systems and identify the key material systems having potential for substantial payoff relative to the primary requirements of light weight and reduced cost for future systems. Current programs and future research opportunities will be described in the presentation which will focus on materials and processes issues.

  5. Light weight, high-speed, and self-powered wireless fiber optic sensor (WiFOS) structural health monitor system for avionics and aerospace environments

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

    2014-09-01

    This paper describes recent progress towards the development of an innovative light weight, high-speed, and selfpowered wireless fiber optic sensor (WiFOS™) structural health monitor system suitable for the onboard and in-flight unattended detection, localization, and classification of load, fatigue, and structural damage in advanced composite materials commonly used in avionics and aerospace systems. The WiFOS™ system is based on ROI's advancements on monolithic photonic integrated circuit microchip technology, integrated with smart power management, on-board data processing, wireless data transmission optoelectronics, and self-power using energy harvesting tools such as solar, vibration, thermoelectric, and magneto-electric. The self-powered, wireless WiFOS™ system offers a versatile and powerful SHM tool to enhance the reliability and safety of avionics platforms, jet fighters, helicopters, commercial aircraft that use lightweight composite material structures, by providing comprehensive information about the structural integrity of the structure from a large number of locations. Immediate SHM applications are found in rotorcraft and aircraft, ships, submarines, and in next generation weapon systems, and in commercial oil and petrochemical, aerospace industries, civil structures, power utilities, portable medical devices, and biotechnology, homeland security and a wide spectrum of other applications.

  6. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  7. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center_dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  8. Futurepath: The Story of Research and Technology at NASA Lewis Research Center. Structures for Flight Propulsion, ARC Sprayed Monotape, National Aero-Space Plane

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The story of research and technology at NASA Lewis Research Center's Structures Division is presented. The job and designs of the Structures Division needed for flight propulsion is described including structural mechanics, structural dynamics, fatigue, and fracture. The video briefly explains why properties of metals used in structural mechanics need to be tested. Examples of tests and simulations used in structural dynamics (bodies in motion) are briefly described. Destructive and non-destructive fatigue/fracture analysis is also described. The arc sprayed monotape (a composite material) is explained, as are the programs in which monotape plays a roll. Finally, the National Aero-Space Plane (NASP or x-30) is introduced, including the material development and metal matrix as well as how NASP will reduce costs for NASA.

  9. Electronics speckle interferometry applications for NDE of spacecraft structural components

    NASA Astrophysics Data System (ADS)

    Rao, M. V.; Samuel, R.; Ananthan, A.; Dasgupta, S.; Nair, P. S.

    2008-09-01

    The spacecraft components viz., central cylinder, deck plates, solar panel substrates, antenna reflectors are made of aluminium/composite honeycomb sandwich construction. Detection of these defects spacecraft structural components is important to assess the integrity of the spacecraft structure. Electronic Speckle Interferometry (ESI) techniques identify the defects as anomalous regions in the interferometric fringe patterns of the specklegram while the component is suitably stressed to give rise to differential displacement/strain around the defective region. Calibration studies, different phase shifting methods associated with ESI and the development of a prototype Twin Head ESSI System (THESSIS) and its use for the NDE of a typical satellite structural component are presented.

  10. 35th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Compiler); Doty, Laura W. (Technical Monitor)

    2001-01-01

    The proceedings of the 35th Aerospace Mechanisms Symposium are reported. Ames Research Center hosted the conference, which was held at the Four Points Sheraton, Sunnyvale, California, on May 9-11, 2001. The symposium was sponsored by the Mechanisms Education Association. Technology areas covered included bearings and tribology; pointing, solar array, and deployment mechanisms; and other mechanisms for spacecraft and large space structures.

  11. The universal scissor component: Optimization of a reconfigurable component for deployable scissor structures

    NASA Astrophysics Data System (ADS)

    Alegria Mira, Lara; Thrall, Ashley P.; De Temmerman, Niels

    2016-02-01

    Deployable scissor structures are well equipped for temporary and mobile applications since they are able to change their form and functionality. They are structural mechanisms that transform from a compact state to an expanded, fully deployed configuration. A barrier to the current design and reuse of scissor structures, however, is that they are traditionally designed for a single purpose. Alternatively, a universal scissor component (USC)-a generalized element which can achieve all traditional scissor types-introduces an opportunity for reuse in which the same component can be utilized for different configurations and spans. In this article, the USC is optimized for structural performance. First, an optimized length for the USC is determined based on a trade-off between component weight and structural performance (measured by deflections). Then, topology optimization, using the simulated annealing algorithm, is implemented to determine a minimum weight layout of beams within a single USC component.

  12. Nonthermal Components in the Large Scale Structure

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco

    2004-12-01

    I address the issue of nonthermal processes in the large scale structure of the universe. After reviewing the properties of cosmic shocks and their role as particle accelerators, I discuss the main observational results, from radio to γ-ray and describe the processes that are thought be responsible for the observed nonthermal emissions. Finally, I emphasize the important role of γ-ray astronomy for the progress in the field. Non detections at these photon energies have already allowed us important conclusions. Future observations will tell us more about the physics of the intracluster medium, shocks dissipation and CR acceleration.

  13. Application of composites to the selective reinforcement of metallic aerospace structures. [application of structural design criteria for weight reduction

    NASA Technical Reports Server (NTRS)

    Brooks, W. A., Jr.; Mathauser, E. E.; Pride, R. A.

    1972-01-01

    The use of composite materials to selectively reinforce metallic structures provides a low-cost way to reduce weight and a means of minimizing the risks usually associated with the introduction of new materials. An overview is presented of the NASA Langley Research Center programs to identify the advantages and to develop the potential of the selective reinforcement approach to the use of composites. These programs have shown that selective reinforcement provides excellent strength and stiffness improvements to metallic structures. Significant weight savings can be obtained in a cost effective manner. Flight service programs which have been initiated to validate further the merits of selective reinforcement are described.

  14. Aerospace applications of magnetic bearings

    NASA Technical Reports Server (NTRS)

    Downer, James; Goldie, James; Gondhalekar, Vijay; Hockney, Richard

    1994-01-01

    Magnetic bearings have traditionally been considered for use in aerospace applications only where performance advantages have been the primary, if not only, consideration. Conventional wisdom has been that magnetic bearings have certain performance advantages which must be traded off against increased weight, volume, electric power consumption, and system complexity. These perceptions have hampered the use of magnetic bearings in many aerospace applications because weight, volume, and power are almost always primary considerations. This paper will review progress on several active aerospace magnetic bearings programs at SatCon Technology Corporation. The magnetic bearing programs at SatCon cover a broad spectrum of applications including: a magnetically-suspended spacecraft integrated power and attitude control system (IPACS), a magnetically-suspended momentum wheel, magnetic bearings for the gas generator rotor of a turboshaft engine, a vibration-attenuating magnetic bearing system for an airborne telescope, and magnetic bearings for the compressor of a space-rated heat pump system. The emphasis of these programs is to develop magnetic bearing technologies to the point where magnetic bearings can be truly useful, reliable, and well tested components for the aerospace community.

  15. The 20th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Numerous topics related to aerospace mechanisms were discussed. Deployable structures, electromagnetic devices, tribology, hydraulic actuators, positioning mechanisms, electric motors, communication satellite instruments, redundancy, lubricants, bearings, space stations, rotating joints, and teleoperators are among the topics covered.

  16. The 24th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The proceedings of the symposium are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, latches, connectors, and other mechanisms for large space structures.

  17. Supercomputing in Aerospace

    NASA Technical Reports Server (NTRS)

    Kutler, Paul; Yee, Helen

    1987-01-01

    Topics addressed include: numerical aerodynamic simulation; computational mechanics; supercomputers; aerospace propulsion systems; computational modeling in ballistics; turbulence modeling; computational chemistry; computational fluid dynamics; and computational astrophysics.

  18. Aerospace Applications of Microprocessors

    NASA Technical Reports Server (NTRS)

    1980-01-01

    An assessment of the state of microprocessor applications is presented. Current and future requirements and associated technological advances which allow effective exploitation in aerospace applications are discussed.

  19. Closeup view of Flume Bridge #4 showing structural components. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Close-up view of Flume Bridge #4 showing structural components. Looking northeast - Childs-Irving Hydroelectric Project, Childs System, Flume Bridge No. 4, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  20. Block-Krylov component synthesis method for structural model reduction

    NASA Technical Reports Server (NTRS)

    Craig, Roy R., Jr.; Hale, Arthur L.

    1988-01-01

    A new analytical method is presented for generating component shape vectors, or Ritz vectors, for use in component synthesis. Based on the concept of a block-Krylov subspace, easily derived recurrence relations generate blocks of Ritz vectors for each component. The subspace spanned by the Ritz vectors is called a block-Krylov subspace. The synthesis uses the new Ritz vectors rather than component normal modes to reduce the order of large, finite-element component models. An advantage of the Ritz vectors is that they involve significantly less computation than component normal modes. Both 'free-interface' and 'fixed-interface' component models are derived. They yield block-Krylov formulations paralleling the concepts of free-interface and fixed-interface component modal synthesis. Additionally, block-Krylov reduced-order component models are shown to have special disturbability/observability properties. Consequently, the method is attractive in active structural control applications, such as large space structures. The new fixed-interface methodology is demonstrated by a numerical example. The accuracy is found to be comparable to that of fixed-interface component modal synthesis.

  1. Probabilistic structural analysis methods for space propulsion system components

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1986-01-01

    The development of a three-dimensional inelastic analysis methodology for the Space Shuttle main engine (SSME) structural components is described. The methodology is composed of: (1) composite load spectra, (2) probabilistic structural analysis methods, (3) the probabilistic finite element theory, and (4) probabilistic structural analysis. The methodology has led to significant technical progress in several important aspects of probabilistic structural analysis. The program and accomplishments to date are summarized.

  2. Probabilistic structural analysis methods for space propulsion system components

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    1987-01-01

    The development of a three-dimensional inelastic analysis methodology for the Space Shuttle main engine (SSME) structural components is described. The methodology is composed of: (1) composite load spectra, (2) probabilistic structural analysis methods, (3) the probabilistic finite element theory, and (4) probabilistic structural analysis. The methodology has led to significant technical progress in several important aspects of probabilistic structural analysis. The program and accomplishments to date are summarized.

  3. New environmental regulation for the aerospace industry: The aerospace NESHAP

    SciTech Connect

    Bauer, J.P.; Gampper, B.P.; Baker, J.M.

    1997-12-31

    40 CFR Part 63, Subpart GG, the National Emission Standard for Hazardous Air Pollutants for Aerospace Manufacturing and Rework Facilities, commonly referred to as the Aerospace NESHAP, was issued on September 1, 1995 and requires compliance by September 1, 1998. The regulation affects any facility that manufactures or reworks commercial, civil, or military aircraft vehicles or components and is a major source of Hazardous Air Pollutants (HAPs). The regulation targets reducing Volatile Organic Compound (VOC) and Hazardous Air Pollutant (HAP) emissions to the atmosphere. Processes affected by the new regulation include aircraft painting, paint stripping, chemical milling masking, solvent cleaning, and spray gun cleaning. Regulatory requirements affecting these processes are summarized, and different compliance options compared in terms of cost-effectiveness and industry acceptance. Strategies to reduce compliance costs and minimize recordkeeping burdens are also presented.

  4. Sensor modules for structural health monitoring and reliability of components

    NASA Astrophysics Data System (ADS)

    Kroening, Michael; Berthold, Axel; Meyendorf, Norbert

    2005-05-01

    Safety and availability of ageing infrastructures require periodic or continuous monitoring of the structure"s integrity. Innovative design criteria for new infrastructure components may allow material and energy conservation if components are continuously monitored by using advanced sensor systems. This concept for recurring Structural Health Monitoring will replace a significant part of conventional NDE by new maintenance concepts. The goal consists in sensor networks based on advanced principles of testing technology with integrated signal/data processing and data communication. NDE modeling is required for the quantification of measurement results. Finally, a decision on the integrity of the structure based on sensor results requires detailed knowledge about material behavior and modeling capacity for materials and components. IZFP has developed sensor concepts for complex solutions applicable to Structural Health Monitoring for different applications. These applications include railroad inspection, aircraft inspection, inspection of wind energy systems, power electric switches and micro gas valves. Basic concepts and applications of sensor networks will be presented.

  5. Characterization of damped structural connections for multi-component systems

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Huckelbridge, Arthur A.

    1989-01-01

    The inability to model connections adequately has historically limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurataely model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode Synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection stiffness and damping properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model.

  6. Characterization of damped structural connections for multi-component systems

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Huckelbridge, Arthur A.

    1988-01-01

    The inability to model connections adequately has historically limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode Synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection stiffness and damping properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model.

  7. Engine structures analysis software: Component Specific Modeling (COSMO)

    NASA Astrophysics Data System (ADS)

    McKnight, R. L.; Maffeo, R. J.; Schwartz, S.

    1994-08-01

    A component specific modeling software program has been developed for propulsion systems. This expert program is capable of formulating the component geometry as finite element meshes for structural analysis which, in the future, can be spun off as NURB geometry for manufacturing. COSMO currently has geometry recipes for combustors, turbine blades, vanes, and disks. Component geometry recipes for nozzles, inlets, frames, shafts, and ducts are being added. COSMO uses component recipes that work through neutral files with the Technology Benefit Estimator (T/BEST) program which provides the necessary base parameters and loadings. This report contains the users manual for combustors, turbine blades, vanes, and disks.

  8. Engine Structures Analysis Software: Component Specific Modeling (COSMO)

    NASA Technical Reports Server (NTRS)

    Mcknight, R. L.; Maffeo, R. J.; Schwartz, S.

    1994-01-01

    A component specific modeling software program has been developed for propulsion systems. This expert program is capable of formulating the component geometry as finite element meshes for structural analysis which, in the future, can be spun off as NURB geometry for manufacturing. COSMO currently has geometry recipes for combustors, turbine blades, vanes, and disks. Component geometry recipes for nozzles, inlets, frames, shafts, and ducts are being added. COSMO uses component recipes that work through neutral files with the Technology Benefit Estimator (T/BEST) program which provides the necessary base parameters and loadings. This report contains the users manual for combustors, turbine blades, vanes, and disks.

  9. The development of aerospace polyimide adhesives

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; St.clair, T. L.

    1983-01-01

    Few materials are available which can be used as aerospace adhesives at temperatures in the range of 300 C. The Materials Division at NASA-Langley Research Center developed several high temperature polyimide adhesives to fulfill the stringent needs of current aerospace programs. These adhesives are the result of a decade of basic research studies on the structure property relationships of both linear and addition aromatic polyimides. The development of both in house and commercially available polyimides is reviewed with regards to their potential for use as aerospace adhesives.

  10. NASA service experience with composite components. [for aircraft structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.; Chapman, A. J.

    1980-01-01

    NASA Langley has been active in sponsoring flight service programs with advanced composites during the past decade. A broad data base and confidence in the durability of composite structures are being developed. Flight service experience is reported for more than 140 composite aircraft components with up to 8 years service and almost two million successful component flight hours. Composite components are being evaluated on Boeing, Douglas, and Lockheed transport aircraft. Components are currently under development for service evaluation on Bell and Sikorsky helicopters. Design concepts and inspection and maintenance results are reported for components currently in service. Components under development in the NASA Aircraft Energy Efficiency (ACEE) program are discussed. Results of flight, outdoor ground, and controlled laboratory environmental tests on composite materials used in the flight service programs are also presented.

  11. 38th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Compiler)

    2006-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, the National Aeronautics and Space Administration and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 38th symposium, the AMS continues to be well attended, attracting participants from both the U.S. and abroad. The 38th AMs, hosted by the NASA Langley Research Center in Williamsburg, Virginia, was held May 17-19, 2006. During these three days, 34 papers were presented. Topics included gimbals, tribology, actuators, aircraft mechanisms, deployment mechanisms, release mechanisms, and test equipment. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components.

  12. 37th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Compiler)

    2004-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is reporting problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, NASA and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 37th symposium, the AMS continues to be well attended, attracting participants from both the U.S. and abroad. The 37th AMS, hosted by the Johnson Space Center (JSC) in Galveston, Texas, was held May 19, 20 and 21, 2004. During these three days, 34 papers were presented. Topics included deployment mechanisms, tribology, actuators, pointing and optical mechanisms, Space Station and Mars Rover mechanisms, release mechanisms, and test equipment. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components.

  13. 39th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, E. A. (Compiler)

    2008-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production, and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, NASA Marshall Space Flight Center (MSFC) and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 39th symposium, the AMS continues to be well attended, attracting participants from both the United States and abroad. The 39th AMS was held in Huntsville, Alabama, May 7-9, 2008. During these 3 days, 34 papers were presented. Topics included gimbals and positioning mechanisms, tribology, actuators, deployment mechanisms, release mechanisms, and sensors. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components.

  14. 34th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Compiler)

    2000-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. The National Aeronautics and Space Administration and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for organizing the AMS. Now in its 34th year, the AMS continues to be well attended, attracting participants from both the U.S. and abroad. The 34th AMS, hosted by the Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, was held May 10, 11 and 12, 2000. During these three days, 34 papers were presented. Topics included deployment mechanisms, bearings, actuators, pointing and optical mechanisms, Space Station mechanisms, release mechanisms, and test equipment. Hardware displays during the vendor fair gave attendees an opportunity to meet with developers of current and future mechanism components.

  15. Simplified design procedures for fiber composite structural components/joints

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Chamis, Christos C.

    1990-01-01

    Simplified step-by-step design procedures are summarized, which are suitable for the preliminary design of composite structural components such as panels (laminates) and composite built-up structures (box beams). Similar procedures are also summarized for the preliminary design of composite bolted and adhesively bonded joints. The summary is presented in terms of sample design cases complemented with typical results. Guidelines are provided which can be used in the design selection process of composite structural components/joints. Also, procedures to account for cyclic loads, hygrothermal effects and lamination residual stresses are included.

  16. Weight minimization of structural components for launch in space shuttle

    NASA Technical Reports Server (NTRS)

    Patnaik, Surya N.; Gendy, Atef S.; Hopkins, Dale A.; Berke, Laszlo

    1994-01-01

    Minimizing the weight of structural components of the space station launched into orbit in a space shuttle can save cost, reduce the number of space shuttle missions, and facilitate on-orbit fabrication. Traditional manual design of such components, although feasible, cannot represent a minimum weight condition. At NASA Lewis Research Center, a design capability called CometBoards (Comparative Evaluation Test Bed of Optimization and Analysis Routines for the Design of Structures) has been developed especially for the design optimization of such flight components. Two components of the space station - a spacer structure and a support system - illustrate the capability of CometBoards. These components are designed for loads and behavior constraints that arise from a variety of flight accelerations and maneuvers. The optimization process using CometBoards reduced the weights of the components by one third from those obtained with traditional manual design. This paper presents a brief overview of the design code CometBoards and a description of the space station components, their design environments, behavior limitations, and attributes of their optimum designs.

  17. Probabilistic lifetime strength of aerospace materials via computational simulation

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Keating, Jerome P.; Lovelace, Thomas B.; Bast, Callie C.

    1991-01-01

    The results of a second year effort of a research program are presented. The research included development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic phenomenological constitutive relationship, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects of primitive variables. These primitive variables often originate in the environment and may include stress from loading, temperature, chemical, or radiation attack. This multifactor interaction constitutive equation is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the constitutive equation using actual experimental materials data together with the multiple linear regression of that data.

  18. Magnetic Gearboxes for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Perez-Diaz, Jose Luis; Diez-Jimenez, Efren; Alvarez-Valenzuela, Marco A.; Sanchez-Garcia-Casarrubios, Juan; Cristache, Christian; Valiente-Blanco, Ignacio

    2014-01-01

    Magnetic gearboxes are contactless mechanisms for torque-speed conversion. They present no wear, no friction and no fatigue. They need no lubricant and can be customized for other mechanical properties as stiffness or damping. Additionally, they can protect structures and mechanisms against overloads, limitting the transmitted torque. In this work, spur, planetary and "magdrive" or "harmonic drive" configurations are compared considering their use in aerospace applications. The most recent test data are summarized to provide some useful help for the design engineer.

  19. Fatigue crack propagation in aerospace aluminum alloys

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Piascik, R. S.; Dicus, D. L.; Newman, J. C., Jr.

    1990-01-01

    This paper reviews fracture mechanics based, damage tolerant characterizations and predictions of fatigue crack growth in aerospace aluminum alloys. The results of laboratory experimentation and modeling are summarized in the areas of: (1) fatigue crack closure, (2) the wide range crack growth rate response of conventional aluminum alloys, (3) the fatigue behavior of advanced monolithic aluminum alloys and metal matrix composites, (4) the short crack problem, (5) environmental fatigue, and (6) variable amplitude loading. Remaining uncertainties and necessary research are identified. This work provides a foundation for the development of fatigue resistant alloys and composites, next generation life prediction codes for new structural designs and extreme environments, and to counter the problem of aging components.

  20. Structural Analysis Methods Development for Turbine Hot Section Components

    NASA Technical Reports Server (NTRS)

    Thompson, Robert L.

    1988-01-01

    The structural analysis technologies and activities of the NASA Lewis Research Center's gas turbine engine Hot Section Technology (HOST) program are summarized. The technologies synergistically developed and validated include: time-varying thermal/mechanical load models; component-specific automated geometric modeling and solution strategy capabilities; advanced inelastic analysis methods; inelastic constitutive models; high-temperature experimental techniques and experiments; and nonlinear structural analysis codes. Features of the program that incorporate the new technologies and their application to hot section component analysis and design are described. Improved and, in some cases, first-time 3-D nonlinear structural analyses of hot section components of isotropic and anisotropic nickel-base superalloys are presented.

  1. Structural analysis of ultra-high speed aircraft structural components

    NASA Technical Reports Server (NTRS)

    Lenzen, K. H.; Siegel, W. H.

    1977-01-01

    The buckling characteristics of a hypersonic beaded skin panel were investigated under pure compression with boundary conditions similar to those found in a wing mounted condition. The primary phases of analysis reported include: (1) experimental testing of the panel to failure; (2) finite element structural analysis of the beaded panel with the computer program NASTRAN; and (3) summary of the semiclassical buckling equations for the beaded panel under purely compressive loads. A comparison of each of the analysis methods is also included.

  2. Aerospace safety advisory panel

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Aerospace Safety Advisory Panel (ASAP) monitored NASA's activities and provided feedback to the NASA Administrator, other NASA officials and Congress throughout the year. Particular attention was paid to the Space Shuttle, its launch processing and planned and potential safety improvements. The Panel monitored Space Shuttle processing at the Kennedy Space Center (KSC) and will continue to follow it as personnel reductions are implemented. There is particular concern that upgrades in hardware, software, and operations with the potential for significant risk reduction not be overlooked due to the extraordinary budget pressures facing the agency. The authorization of all of the Space Shuttle Main Engine (SSME) Block II components portends future Space Shuttle operations at lower risk levels and with greater margins for handling unplanned ascent events. Throughout the year, the Panel attempted to monitor the safety activities related to the Russian involvement in both space and aeronautics programs. This proved difficult as the working relationships between NASA and the Russians were still being defined as the year unfolded. NASA's concern for the unique safety problems inherent in a multi-national endeavor appears appropriate. Actions are underway or contemplated which should be capable of identifying and rectifying problem areas. The balance of this report presents 'Findings and Recommendations' (Section 2), 'Information in Support of Findings and Recommendations' (Section 3) and Appendices describing Panel membership, the NASA response to the March 1994 ASAP report, and a chronology of the panel's activities during the reporting period (Section 4).

  3. Probabilistic material degradation model for aerospace materials subjected to high temperature, mechanical and thermal fatigue, and creep

    NASA Technical Reports Server (NTRS)

    Boyce, L.

    1992-01-01

    A probabilistic general material strength degradation model has been developed for structural components of aerospace propulsion systems subjected to diverse random effects. The model has been implemented in two FORTRAN programs, PROMISS (Probabilistic Material Strength Simulator) and PROMISC (Probabilistic Material Strength Calibrator). PROMISS calculates the random lifetime strength of an aerospace propulsion component due to as many as eighteen diverse random effects. Results are presented in the form of probability density functions and cumulative distribution functions of lifetime strength. PROMISC calibrates the model by calculating the values of empirical material constants.

  4. Probabilistic structural analysis methods for critical SSME propulsion components

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1986-01-01

    The development of a three-dimensional inelastic analysis methodology for the Space Shuttle main engine (SSME) structural components is described. The methodology is composed of: (1) composite load spectra, (2) probabilistic structural analysis methods, (3) the probabilistic finite element theory, and (4) probabilistic structural analysis. The progress in the development of generic probabilistic models for various individual loads which consist of a steady state load, a periodic load, a random load, and a spike, is discussed. The capabilities of the Numerical Evaluation of Stochastic Structures Under Stress finite element code designed for probabilistic structural analysis of the SSME are examined. Variation principles for formulation probabilistic finite elements and a structural analysis for evaluating the geometric and material properties tolerances on the structural response of turbopump blades are being designed.

  5. HASA: Hypersonic Aerospace Sizing Analysis for the Preliminary Design of Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Harloff, Gary J.; Berkowitz, Brian M.

    1988-01-01

    A review of the hypersonic literature indicated that a general weight and sizing analysis was not available for hypersonic orbital, transport, and fighter vehicles. The objective here is to develop such a method for the preliminary design of aerospace vehicles. This report describes the developed methodology and provides examples to illustrate the model, entitled the Hypersonic Aerospace Sizing Analysis (HASA). It can be used to predict the size and weight of hypersonic single-stage and two-stage-to-orbit vehicles and transports, and is also relevant for supersonic transports. HASA is a sizing analysis that determines vehicle length and volume, consistent with body, fuel, structural, and payload weights. The vehicle component weights are obtained from statistical equations for the body, wing, tail, thermal protection system, landing gear, thrust structure, engine, fuel tank, hydraulic system, avionics, electral system, equipment payload, and propellant. Sample size and weight predictions are given for the Space Shuttle orbiter and other proposed vehicles, including four hypersonic transports, a Mach 6 fighter, a supersonic transport (SST), a single-stage-to-orbit (SSTO) vehicle, a two-stage Space Shuttle with a booster and an orbiter, and two methane-fueled vehicles.

  6. PREFACE: Trends in Aerospace Manufacturing 2009 International Conference

    NASA Astrophysics Data System (ADS)

    Ridgway, Keith; Gault, Rosemary; Allen, Adrian

    2011-12-01

    The aerospace industry is rapidly changing. New aircraft structures are being developed and aero-engines are becoming lighter and more environmentally friendly. In both areas, innovative materials and manufacturing methods are used in an attempt to get maximum performance for minimum cost. At the same time, the structure of the industry has changed and there has been a move from large companies designing, manufacturing components and assembling aircraft to one of large global supply chains headed by large system integrators. All these changes have forced engineers and managers to bring in innovations in design, materials, manufacturing technologies and supply chain management. In September 2009, the Advanced Manufacturing Research Centre (AMRC) at the University of Sheffield held the inaugural Trends in Aerospace Manufacturing conference (TRAM09). This brought together 28 speakers over two days, who presented in sessions on advanced manufacturing trends for the aerospace sector. Areas covered included new materials, including composites, advanced machining, state of the art additive manufacturing techniques, assembly and supply chain issues.

  7. High frequency guided ultrasonic waves for hidden fatigue crack growth monitoring in multi-layer model aerospace structures

    NASA Astrophysics Data System (ADS)

    Chan, Henry; Masserey, Bernard; Fromme, Paul

    2015-02-01

    Especially for ageing aircraft the development of fatigue cracks at fastener holes due to stress concentration and varying loading conditions constitutes a significant maintenance problem. High frequency guided waves offer a potential compromise between the capabilities of local bulk ultrasonic measurements with proven defect detection sensitivity and the large area coverage of lower frequency guided ultrasonic waves. High frequency guided waves have energy distributed through all layers of the specimen thickness, allowing in principle hidden (2nd layer) fatigue damage monitoring. For the integration into structural health monitoring systems the sensitivity for the detection of hidden fatigue damage in inaccessible locations of the multi-layered components from a stand-off distance has to be ascertained. The multi-layered model structure investigated consists of two aluminium plate-strips with an epoxy sealant layer. During cyclic loading fatigue crack growth at a fastener hole was monitored. Specific guided wave modes (combination of fundamental A0 and S0 Lamb modes) were selectively excited above the cut-off frequencies of higher modes using a standard ultrasonic wedge transducer. Non-contact laser measurements close to the defect were performed to qualify the influence of a fatigue crack in one aluminium layer on the guided wave scattering. Fatigue crack growth monitoring using laser interferometry showed good sensitivity and repeatability for the reliable detection of small, quarter-elliptical cracks. Standard ultrasonic pulse-echo equipment was employed to monitor hidden fatigue damage from a stand-off distance without access to the damaged specimen layer. Sufficient sensitivity for the detection of fatigue cracks located in the inaccessible aluminium layer was verified, allowing in principle practical in situ ultrasonic monitoring of fatigue crack growth.

  8. Identification of structural interface characteristics using component mode synthesis

    NASA Technical Reports Server (NTRS)

    Huckelbridge, A. A.; Lawrence, C.

    1987-01-01

    The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig are presented.

  9. Identification of structural interface characteristics using component mode synthesis

    NASA Technical Reports Server (NTRS)

    Huckelbridge, A. A.; Lawrence, C.

    1987-01-01

    The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig, are presented.

  10. Identification of structural interface characteristics using component mode synthesis

    NASA Technical Reports Server (NTRS)

    Huckelbridge, A. A.; Lawrence, C.

    1989-01-01

    The inability to adequately model connections has limited the ability to predict overall system dynamic response. Connections between structural components are often mechanically complex and difficult to accurately model analytically. Improved analytical models for connections are needed to improve system dynamic predictions. This study explores combining Component Mode synthesis methods for coupling structural components with Parameter Identification procedures for improving the analytical modeling of the connections. Improvements in the connection properties are computed in terms of physical parameters so the physical characteristics of the connections can be better understood, in addition to providing improved input for the system model. Two sample problems, one utilizing simulated data, the other using experimental data from a rotor dynamic test rig, are presented.

  11. Biological Insights from Structures of Two-Component Proteins

    PubMed Central

    Gao, Rong; Stock, Ann M.

    2013-01-01

    Two-component signal transduction based on phosphotransfer from a histidine protein kinase to a response regulator protein is a prevalent strategy for coupling environmental stimuli to adaptive responses in bacteria. In both histidine kinases and response regulators, modular domains with conserved structures and biochemical activities adopt different conformational states in the presence of stimuli or upon phosphorylation, enabling a diverse array of regulatory mechanisms based on inhibitory and/or activating protein-protein interactions imparted by different domain arrangements. This review summarizes some of the recent structural work that has provided insight to the functioning of bacterial histidine kinases and response regulators. Particular emphasis is placed on identifying features that are expected to be conserved among different two-component proteins from those that are expected to differ, with the goal of defining the extent to which knowledge of previously characterized two-component proteins can be applied to newly discovered systems. PMID:19575571

  12. Experimental component mode synthesis of structures with sloppy joints

    NASA Technical Reports Server (NTRS)

    Blackwood, Gary H.; Von Flotow, A. H.

    1988-01-01

    The accuracy of component mode synthesis is investigated experimentally for substructures coupled by nonideal joints. The work is based upon a segmented experimental beam for which free-interface frequency response matrices are measured for each segment. These measurements are used directly in component mode synthesis to predict the behavior of the assembled structure; the segments are then physically joined, and the resulting frequency response of the superstructure is compared to the prediction. Rotational freeplay is then introduced into the connecting joint, and the new superstructure frequency response is compared to the original linear component mode synthesis prediction. The level of accuracy to be expected in component mode synthesis is discussed in terms of the degree of nonlinearity in the joints, mode number, and mode shapes.

  13. Evaluating Aerospace Workshops.

    ERIC Educational Resources Information Center

    Leonard, Rex L.

    1978-01-01

    Declining enrollments in aerospace teacher workshops suggest the need for evaluation and cost effectiveness measurements. A major purpose of this article is to illustrate some typical evaluation methodologies, including the semantic differential. (MA)

  14. Aerospace bibliography, seventh edition

    NASA Technical Reports Server (NTRS)

    Blashfield, J. F. (Compiler)

    1983-01-01

    Space travel, planetary probes, applications satellites, manned spaceflight, the impacts of space exploration, future space activities, astronomy, exobiology, aeronautics, energy, space and the humanities, and aerospace education are covered.

  15. Ninteenth Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The proceedings of the 19th Aerospace Mechanisms Symposium are reported. Technological areas covered include space lubrication, bearings, aerodynamic devices, spacecraft/Shuttle latches, deployment, positioning, and pointing. Devices for spacecraft docking and manipulator and teleoperator mechanisms are also described.

  16. NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 12: The diffusion of federally funded aerospace research and development (R/D) and the information seeking behavior of US aerospace engineers and scientists

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Kennedy, John M.; Barclay, Rebecca O.

    1991-01-01

    In this paper, the diffusion of federally funded aerospace R&D is explored from the perspective of the information-seeking behavior of U.S. aerospace engineers and scientists. The following three assumptions frame this exploration: (1) knowledge production, transfer, and utilization are equally important components of the aerospace R&D process; (2) the diffusion of knowledge resulting from federally funded aerospace R&D is indispensable for the U.S. to remain a world leader in aerospace; and (3) U.S. government technical reports, produced by NASA and DOD, play an important, but as yet undefined, role in the diffusion of federally funded aerospace R&D. A conceptual model for federally funded aerospace knowledge diffusion, one that emphasizes U.S. goverment technical reports, is presented. Data regarding three research questions concerning the information-seeking behavior of U.S. aerospace engineers and scientists are also presented.

  17. Beyond lamins: other structural components of the nucleoskeleton

    PubMed Central

    Zhong, Zhixia; Wilson, Katherine L.; Dahl, Kris Noel

    2010-01-01

    The nucleus is bordered by a double bilayer nuclear envelope, communicates with the cytoplasm via embedded nuclear pore complexes, and is structurally supported by an underlying nucleoskeleton. The nucleoskeleton includes nuclear intermediate filaments formed by lamin proteins, which provide major structural and mechanical support to the nucleus. However other structural proteins also contribute to the function of nucleoskeleton and help connect it to the cytoskeleton. This chapter reviews nucleoskeletal components beyond lamins, and summarizes specific methods and strategies useful for analyzing nuclear structural proteins including actin, spectrin, titin, LINC complex proteins and nuclear spindle matrix proteins. These components can localize to highly specific functional subdomains at the nuclear envelope or nuclear interior, and can interact either stably or dynamically with a variety of partners. These components confer upon the nucleoskeleton a functional diversity and mechanical resilience that appears to rival the cytoskeleton. To facilitate the exploration of this understudied area of biology, we summarize methods useful for localizing, solubilizing and immunoprecipitating nuclear structural proteins, and a state-of-the-art method to measure a newly-recognized mechanical property of nucleus. PMID:20816232

  18. Beyond lamins other structural components of the nucleoskeleton.

    PubMed

    Zhong, Zhixia; Wilson, Katherine L; Dahl, Kris Noel

    2010-01-01

    The nucleus is bordered by a double bilayer nuclear envelope, communicates with the cytoplasm via embedded nuclear pore complexes, and is structurally supported by an underlying nucleoskeleton. The nucleoskeleton includes nuclear intermediate filaments formed by lamin proteins, which provide major structural and mechanical support to the nucleus. However, other structural proteins also contribute to the function of the nucleoskeleton and help connect it to the cytoskeleton. This chapter reviews nucleoskeletal components beyond lamins and summarizes specific methods and strategies useful for analyzing nuclear structural proteins including actin, spectrin, titin, linker of nucleoskeleton and cytoskeleton (LINC) complex proteins, and nuclear spindle matrix proteins. These components can localize to highly specific functional subdomains at the nuclear envelope or nuclear interior and can interact either stably or dynamically with a variety of partners. These components confer upon the nucleoskeleton a functional diversity and mechanical resilience that appears to rival the cytoskeleton. To facilitate the exploration of this understudied area of biology, we summarize methods useful for localizing, solubilizing, and immunoprecipitating nuclear structural proteins, and a state-of-the-art method to measure a newly-recognized mechanical property of nucleus. PMID:20816232

  19. Equilibrium Structures of Differentially Rotating Primary Components of Binary Stars

    NASA Astrophysics Data System (ADS)

    Mohan, C.; Lal, A. K.; Singh, V. P.

    1997-11-01

    In this paper a method is proposed for computing the equilibrium structures and various other observable physical parameters of the primary components of stars in binary systems assuming that the primary is more massive than the secondary and is rotating differentially about its axis. Kippenhahn and Thomas averaging approach (1970) is used in a manner earlier used by Mohan, Saxena and Agarwal (1990) to incorporate the rotational and tidal effects in the equations of stellar structure. Explicit expressions for the distortional terms appearing in the stellar structure equations have been obtained by assuming a general law of differential rotation of the typeω2 = b 0+b 1 s 2+b 2 s 4, where ω is the angular velocity of rotation of a fluid element in the star at a distance s from the axis of rotation, and b 0, b 1, b 2 are suitably chosen numerical constants. The expressions incorporate the effects of differential rotation and tidal distortions up to second order terms. The use of the proposed method has been illustrated by applying it to obtain the structures and observable parameters of certain differentially rotating primary components of the binary stars assuming the primary components to have polytropic structures.

  20. Polymer-based composites for aerospace: An overview of IMAST results

    NASA Astrophysics Data System (ADS)

    Milella, Eva; Cammarano, Aniello

    2016-05-01

    This paper gives an overview of technological results, achieved by IMAST, the Technological Cluster on Engineering of Polymeric Composite Materials and Structures, in the completed Research Projects in the aerospace field. In this sector, the Cluster developed different solutions: lightweight multifunctional fiber-reinforced polymer composites for aeronautic structures, advanced manufacturing processes (for the optimization of energy consumption and waste reduction) and multifunctional components (e.g., thermal, electrical, acoustic and fire resistance).

  1. Crystal structure of the RNA component of bacterial ribonuclease P

    SciTech Connect

    Torres-Larios, Alfredo; Swinger, Kerren K.; Krasilnikov, Andrey S.; Pan, Tao; Mondragon, Alfonso

    2010-03-08

    Transfer RNA (tRNA) is produced as a precursor molecule that needs to be processed at its 3' and 5' ends. Ribonuclease P is the sole endonuclease responsible for processing the 5' end of tRNA by cleaving the precursor and leading to tRNA maturation. It was one of the first catalytic RNA molecules identified and consists of a single RNA component in all organisms and only one protein component in bacteria. It is a true multi-turnover ribozyme and one of only two ribozymes (the other being the ribosome) that are conserved in all kingdoms of life. Here we show the crystal structure at 3.85 {angstrom} resolution of the RNA component of Thermotoga maritima ribonuclease P. The entire RNA catalytic component is revealed, as well as the arrangement of the two structural domains. The structure shows the general architecture of the RNA molecule, the inter- and intra-domain interactions, the location of the universally conserved regions, the regions involved in pre-tRNA recognition and the location of the active site. A model with bound tRNA is in agreement with all existing data and suggests the general basis for RNA-RNA recognition by this ribozyme.

  2. 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.

  3. NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 26: The relationship between technology policy and scientific and technical information within the US and Japanese aerospace industries

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Barclay, Rebecca O.; Kennedy, John M.

    1993-01-01

    Government technology policy has nurtured the growth of the aerospace industry which is vital to both the U.S. and Japanese economies. Japanese technology policy differs significantly from U.S. technology policy, however, particularly with respect to the production, transfer, and use of scientific and technical information (STI). In this paper, we discuss the unique position of the aerospace industry in the U.S. and Japan, U.S. and Japanese aerospace policy, and the role of STI in the process of aerospace innovation. The information-seeking behaviors of U.S. and Japanese aerospace engineers and scientists are compared. The authors advocate the development of innovation-adoption technology and STI policy goals for U.S. aerospace and the inclusion of an aerospace knowledge diffusion transfer system with an 'active' component for scanning and acquiring foreign aerospace technology and STI.

  4. Probabilistic structural analysis methods for select space propulsion system components

    NASA Technical Reports Server (NTRS)

    Millwater, H. R.; Cruse, T. A.

    1989-01-01

    The Probabilistic Structural Analysis Methods (PSAM) project developed at the Southwest Research Institute integrates state-of-the-art structural analysis techniques with probability theory for the design and analysis of complex large-scale engineering structures. An advanced efficient software system (NESSUS) capable of performing complex probabilistic analysis has been developed. NESSUS contains a number of software components to perform probabilistic analysis of structures. These components include: an expert system, a probabilistic finite element code, a probabilistic boundary element code and a fast probability integrator. The NESSUS software system is shown. An expert system is included to capture and utilize PSAM knowledge and experience. NESSUS/EXPERT is an interactive menu-driven expert system that provides information to assist in the use of the probabilistic finite element code NESSUS/FEM and the fast probability integrator (FPI). The expert system menu structure is summarized. The NESSUS system contains a state-of-the-art nonlinear probabilistic finite element code, NESSUS/FEM, to determine the structural response and sensitivities. A broad range of analysis capabilities and an extensive element library is present.

  5. Damage rates for FFTF structural components and surveillance assemblies

    SciTech Connect

    Simons, R.L.

    1993-08-01

    The Fast Flux Test Facility (FFTF) surveillance program provides coupon surveillance materials that are irradiated to the expected lifetime damage dose that the represented component will experience. This methodology requires a knowledge of the damage dose rates to the surveillance assemblies and to the critical locations of the structural components. This analysis updates the predicted exposures from a total fluence to a displacement per atom (dpa) basis using Monte Carlo (computer code for) neutron photon (transport) code (MCNP). The MCNP calculation improves the relative consistency and lowers the predicted damage rates uncertainty in a number of out-of-core locations. The results were used an part of the evaluation to extend the lifetime of the invessel components to 30 years in support of multiple missions for FFTF.

  6. Experimental component mode systhesis of structures with nonlinear joints

    NASA Technical Reports Server (NTRS)

    Blackwood, Gary H.; Vonflotow, A. H.

    1988-01-01

    The accuracy of component mode synthesis is investigated experimentally for substructures coupled by non-ideal joints. The work is based upon a segmented experimental beam for which the free-interface frequency response matrices are measured for each segment. These measurements are used directly in component mode synthesis to predict the behavior of the assembled structure; the segments are then physically joined and the resulting frequency response of the superstructure is compared to the prediction. Rotational freeplay is then introduced into the connecting joint and the new superstructure frequency response is compared to the original linear CMS prediction. The level of accuracy to be expected in component mode synthesis is discussed in terms of the degree of nonlinearity in the joints, mode number and mode shapes.

  7. A life prediction model for laminated composite structural components

    NASA Technical Reports Server (NTRS)

    Allen, David H.

    1990-01-01

    A life prediction methodology for laminated continuous fiber composites subjected to fatigue loading conditions was developed. A summary is presented of research completed. A phenomenological damage evolution law was formulated for matrix cracking which is independent of stacking sequence. Mechanistic and physical support was developed for the phenomenological evolution law proposed above. The damage evolution law proposed above was implemented to a finite element computer program. And preliminary predictions were obtained for a structural component undergoing fatigue loading induced damage.

  8. A structured overview of simultaneous component based data integration

    PubMed Central

    Van Deun, Katrijn; Smilde, Age K; van der Werf, Mariët J; Kiers, Henk AL; Van Mechelen, Iven

    2009-01-01

    Background Data integration is currently one of the main challenges in the biomedical sciences. Often different pieces of information are gathered on the same set of entities (e.g., tissues, culture samples, biomolecules) with the different pieces stemming, for example, from different measurement techniques. This implies that more and more data appear that consist of two or more data arrays that have a shared mode. An integrative analysis of such coupled data should be based on a simultaneous analysis of all data arrays. In this respect, the family of simultaneous component methods (e.g., SUM-PCA, unrestricted PCovR, MFA, STATIS, and SCA-P) is a natural choice. Yet, different simultaneous component methods may lead to quite different results. Results We offer a structured overview of simultaneous component methods that frames them in a principal components setting such that both the common core of the methods and the specific elements with regard to which they differ are highlighted. An overview of principles is given that may guide the data analyst in choosing an appropriate simultaneous component method. Several theoretical and practical issues are illustrated with an empirical example on metabolomics data for Escherichia coli as obtained with different analytical chemical measurement methods. Conclusion Of the aspects in which the simultaneous component methods differ, pre-processing and weighting are consequential. Especially, the type of weighting of the different matrices is essential for simultaneous component analysis. These types are shown to be linked to different specifications of the idea of a fair integration of the different coupled arrays. PMID:19671149

  9. [Structural components and peculiarities of Pseudomonas aeruginosa biofilm organization].

    PubMed

    Balko, O B; Avdieieva, L V

    2010-01-01

    Peculiarities of the structural organization of bacterial biofilm during its formation and disintegration have been investigated on the model of Pseudomonas aeruginosa UCM B-900 (ATCC 9027). It was shown, that development of the biofilm in a stationary system on glass was a two-vector process with changes in time and space. P. aeruginosa UCM B-900 biofilm is formed from single cells, passes through the stages of base components, net structure, islands and comes to the end with integration into a complete monolayer. The biofilm degradation repeats the stages of its formation in the reverse sequence. PMID:20812507

  10. Incorporation of a hierarchical grid component structure into GRIDGEN

    NASA Technical Reports Server (NTRS)

    Steinbrenner, John P.; Chawner, John R.

    1993-01-01

    The underlying framework of the GRIDGEN multiple block grid generation system has been refined so that grid components are now stored within a hierarchical data structure. This restructuring has enhanced the usability of the software by allowing grids to be generated on a more intuitive level. This new framework also provides a means by which the multiple block system can be edited at most any level in the grid generation process. Editing tools are currently being added to GRIDGEN so that a change to the grid can be propagated backward and forward in the data hierarchy. The new data structure, the editing tools, and other recent GRIDGEN improvements are described in this paper.

  11. Aircraft fatigue and crack growth considering loads by structural component

    NASA Technical Reports Server (NTRS)

    Yost, J. D.

    1994-01-01

    The indisputable 1968 C-130 fatigue/crack growth data is reviewed to obtain additional useful information on fatigue and crack growth. The proven Load Environment Model concept derived empirically from F-105D multichannel recorder data is refined to a simpler method by going from 8 to 5 variables in the spectra without a decrease in accuracy. This approach provides the true fatigue/crack growth and load environment by structural component for both fatigue and strength design. Methods are presented for defining fatigue scatter and damage at crack initiation. These design tools and criteria may be used for both metal and composite aircraft structure.

  12. The 21st Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1987-01-01

    During the symposium technical topics addressed included deployable structures, electromagnetic devices, tribology, actuators, latching devices, positioning mechanisms, robotic manipulators, and automated mechanisms synthesis. A summary of the 20th Aerospace Mechanisms Symposium panel discussions is included as an appendix. However, panel discussions on robotics for space and large space structures which were held are not presented herein.

  13. An assessment of COMSCAN, a Compton backscatter imaging camera, for the one-sided non-destructive inspection of aerospace components

    NASA Astrophysics Data System (ADS)

    Sponder, L.

    1993-07-01

    This report presents some results obtained using a Compton backscatter imaging camera, developed by Philips Industries, which were obtained during a visit to the Defense Research Establishment Pacific (DREP) during May/June 1992. Compton backscatter imaging is an X-ray technique which can be used to non-destructively inspect the interior of both metallic and non-metallic structures and, unlike conventional X-ray methods, requires access to only one side of the part being inspected.

  14. Conservation of Strategic Aerospace Materials (COSAM)

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1981-01-01

    Research efforts to reduce the dependence of the aerospace industry on strategic metals, such as cobalt (Co), columbium (Cb), tantalum (Ta), and chromium (Cr), by providing the materials technology needed to minimize the strategic metal content of critical aerospace components for gas turbine engines are addressed. Thrusts in three technology areas are identified: near term activities in the area of strategic element substitution; intermediate-range activities in the area of materials processing; and long term, high risk activities in the area of 'new classes' of high temprature metallic materials. Specifically, the role of cobalt in nickel-base and cobalt-base superalloys vital to the aerospace industry is examined along with the mechanical and physical properties of intermetallics that will contain a minimum of the stragetic metals.

  15. Computer-aided design of antenna structures and components

    NASA Technical Reports Server (NTRS)

    Levy, R.

    1976-01-01

    This paper discusses computer-aided design procedures for antenna reflector structures and related components. The primary design aid is a computer program that establishes cross sectional sizes of the structural members by an optimality criterion. Alternative types of deflection-dependent objectives can be selected for designs subject to constraints on structure weight. The computer program has a special-purpose formulation to design structures of the type frequently used for antenna construction. These structures, in common with many in other areas of application, are represented by analytical models that employ only the three translational degrees of freedom at each node. The special-purpose construction of the program, however, permits coding and data management simplifications that provide advantages in problem size and execution speed. Size and speed are essentially governed by the requirements of structural analysis and are relatively unaffected by the added requirements of design. Computation times to execute several design/analysis cycles are comparable to the times required by general-purpose programs for a single analysis cycle. Examples in the paper illustrate effective design improvement for structures with several thousand degrees of freedom and within reasonable computing times.

  16. Advanced Materials and Coatings for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2004-01-01

    In the application area of aerospace tribology, researchers and developers must guarantee the highest degree of reliability for materials, components, and systems. Even a small tribological failure can lead to catastrophic results. The absence of the required knowledge of tribology, as Professor H.P. Jost has said, can act as a severe brake in aerospace vehicle systems-and indeed has already done so. Materials and coatings must be able to withstand the aerospace environments that they encounter, such as vacuum terrestrial, ascent, and descent environments; be resistant to the degrading effects of air, water vapor, sand, foreign substances, and radiation during a lengthy service; be able to withstand the loads, stresses, and temperatures encountered form acceleration and vibration during operation; and be able to support reliable tribological operations in harsh environments throughout the mission of the vehicle. This presentation id divided into two sections: surface properties and technology practice related to aerospace tribology. The first section is concerned with the fundamental properties of the surfaces of solid-film lubricants and related materials and coatings, including carbon nanotubes. The second is devoted to applications. Case studies are used to review some aspects of real problems related to aerospace systems to help engineers and scientists to understand the tribological issues and failures. The nature of each problem is analyzed, and the tribological properties are examined. All the fundamental studies and case studies were conducted at the NASA Glenn Research Center.

  17. Aerospace Environmental Technology Conference

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F. (Editor)

    1995-01-01

    The mandated elimination of CFC's, Halons, TCA, and other ozone depleting chemicals and specific hazardous materials has required changes and new developments in aerospace materials and processes. The aerospace industry has been involved for several years in providing product substitutions, redesigning entire production processes, and developing new materials that minimize or eliminate damage to the environment. These activities emphasize replacement cleaning solvents and their application verifications, compliant coatings including corrosion protection systems, and removal techniques, chemical propulsion effects on the environment, and the initiation of modifications to relevant processing and manufacturing specifications and standards. The Executive Summary of this Conference is published as NASA CP-3297.

  18. Aerospace applications of advanced aluminum alloys

    NASA Technical Reports Server (NTRS)

    Chellman, D. J.; Langenbeck, S. L.

    1993-01-01

    Advanced metallic materials within the Al-base family are being developed for applications on current and future aerospace vehicles. These advanced materials offer significant improvements in density, strength, stiffness, fracture resistance, and/or higher use temperature which translates into improved vehicle performance. Aerospace applications of advanced metallic materials include space structures, fighters, military and commercial transport aircraft, and missiles. Structural design requirements, including not only static and durability/damage tolerance criteria but also environmental considerations, drive material selections. Often trade-offs must be made regarding strength, fracture resistance, cost, reliability, and maintainability in order to select the optimum material for a specific application. These trade studies not only include various metallic materials but also many times include advanced composite materials. Details of material comparisons, aerospace applications, and material trades will be presented.

  19. Managing complexity of aerospace systems

    NASA Astrophysics Data System (ADS)

    Tamaskar, Shashank

    Growing complexity of modern aerospace systems has exposed the limits of conventional systems engineering tools and challenged our ability to design them in a timely and cost effective manner. According to the US Government Accountability Office (GAO), in 2009 nearly half of the defense acquisition programs are expecting 25% or more increase in unit acquisition cost. Increase in technical complexity has been identified as one of the primary drivers behind cost-schedule overruns. Thus to assure the affordability of future aerospace systems, it is increasingly important to develop tools and capabilities for managing their complexity. We propose an approach for managing the complexity of aerospace systems to address this pertinent problem. To this end, we develop a measure that improves upon the state-of-the-art metrics and incorporates key aspects of system complexity. We address the problem of system decomposition by presenting an algorithm for module identification that generates modules to minimize integration complexity. We demonstrate the framework on diverse spacecraft and show the impact of design decisions on integration cost. The measure and the algorithm together help the designer track and manage complexity in different phases of system design. We next investigate how complexity can be used as a decision metric in the model-based design (MBD) paradigm. We propose a framework for complexity enabled design space exploration that introduces the idea of using complexity as a non-traditional design objective. We also incorporate complexity with the component based design paradigm (a sub-field of MBD) and demonstrate it on several case studies. The approach for managing complexity is a small but significant contribution to the vast field of complexity management. We envision our approach being used in concert with a suite of complexity metrics to provide an ability to measure and track complexity through different stages of design and development. This will not

  20. Nde of Bonded Aluminum Components on Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Barnard, Daniel J.; Hsu, David K.; Foreman, Cory; Wendt, Scott; Kreitinger, Nicholas A.; Steffes, Gary J.

    2008-02-01

    Bonded aluminum structures have been commonly used on aircraft for many years, and many of these applications include flight control surfaces. These bonded structures can be made up of aluminum face sheets adhesively bonded to a central honeycomb core, or they could also be composed of machined components that are bonded in a tongue-in-groove type manner called Grid-Lock. Nondestructive Inspection (NDI) methods of bonded aluminum structures usually involve the detection of skin-to-core disbonds, core buckling and damage caused by impacts. In the case of Grid-Lock, NDI techniques are focused on the detection of failures in the tongue-in-groove adhesive joint. Three nondestructive inspection methods were applied to honeycomb sandwich structures and Grid-Lock panels. The three methods were computer aided tap test (CATT), air-coupled ultrasonic testing (ACUT), and mechanical impedance analysis (MIA). The honeycomb structures tested consisted of structural panels and flight control surfaces from various aircraft. The Grid-Lock samples tested are laboratory specimens that simulate various defects. Experimental results and comparisons from each of these methods and samples will be presented.

  1. Composite Load Spectra for Select Space Propulsion Structural Components

    NASA Technical Reports Server (NTRS)

    Ho, Hing W.; Newell, James F.

    1994-01-01

    Generic load models are described with multiple levels of progressive sophistication to simulate the composite (combined) load spectra (CLS) that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades and liquid oxygen (LOX) posts. These generic (coupled) models combine the deterministic models for composite load dynamic, acoustic, high-pressure and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients are then determined using advanced probabilistic simulation methods with and without strategically selected experimental data. The entire simulation process is included in a CLS computer code. Applications of the computer code to various components in conjunction with the PSAM (Probabilistic Structural Analysis Method) to perform probabilistic load evaluation and life prediction evaluations are also described to illustrate the effectiveness of the coupled model approach.

  2. Analytical Approach for Estimating Preliminary Mass of ARES I Crew Launch Vehicle Upper Stage Structural Components

    NASA Technical Reports Server (NTRS)

    Aggarwal, Pravin

    2007-01-01

    electrical power functions to other Elements of the CLV, is included as secondary structure. The MSFC has an overall responsibility for the integrated US element as well as structural design an thermal control of the fuel tanks, intertank, interstage, avionics, main propulsion system, Reaction Control System (RCS) for both the Upper Stage and the First Stage. MSFC's Spacecraft and Vehicle Department, Structural and Analysis Design Division is developing a set of predicted mass of these elements. This paper details the methodology, criterion and tools used for the preliminary mass predictions of the upper stage structural assembly components. In general, weight of the cylindrical barrel sections are estimated using the commercial code Hypersizer, whereas, weight of the domes are developed using classical solutions. HyperSizer is software that performs automated structural analysis and sizing optimization based on aerospace methods for strength, stability, and stiffness. Analysis methods range from closed form, traditional hand calculations repeated every day in industry to more advanced panel buckling algorithms. Margin-of-safety reporting for every potential failure provides the engineer with a powerful insight into the structural problem. Optimization capabilities include finding minimum weight panel or beam concepts, material selections, cross sectional dimensions, thicknesses, and lay-ups from a library of 40 different stiffened and sandwich designs and a database of composite, metallic, honeycomb, and foam materials. Multiple different concepts (orthogrid, isogrid, and skin stiffener) were run for multiple loading combinations of ascent design load with and with out tank pressure as well as proof pressure condition. Subsequently, selected optimized concept obtained from Hypersizer runs was translated into a computer aid design (CAD) model to account for the wall thickness tolerance, weld land etc for developing the most probable weight of the components. The flow diram

  3. NASA-UVa Light Aerospace Alloy and Structures Technology Program: Aluminum-Based Materials for High Speed Aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr. (Editor)

    1996-01-01

    This report is concerned with 'Aluminum-Based Materials for High Speed Aircraft' which was initiated to identify the technology needs associated with advanced, low-cost aluminum base materials for use as primary structural materials. Using a reference baseline aircraft, these materials concept will be further developed and evaluated both technically and economically to determine the most attractive combinations of designs, materials, and manufacturing techniques for major structural sections of an HSCT. Once this has been accomplished, the baseline aircraft will be resized, if applicable, and performance objectives and economic evaluations made to determine aircraft operating costs. The two primary objectives of this study are: (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials, and (2) to assess these materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT.

  4. Residual Strength Analysis Methodology: Laboratory Coupons to Structural Components

    NASA Technical Reports Server (NTRS)

    Dawicke, D. S.; Newman, J. C., Jr.; Starnes, J. H., Jr.; Rose, C. A.; Young, R. D.; Seshadri, B. R.

    2000-01-01

    The NASA Aircraft Structural Integrity (NASIP) and Airframe Airworthiness Assurance/Aging Aircraft (AAA/AA) Programs have developed a residual strength prediction methodology for aircraft fuselage structures. This methodology has been experimentally verified for structures ranging from laboratory coupons up to full-scale structural components. The methodology uses the critical crack tip opening angle (CTOA) fracture criterion to characterize the fracture behavior and a material and a geometric nonlinear finite element shell analysis code to perform the structural analyses. The present paper presents the results of a study to evaluate the fracture behavior of 2024-T3 aluminum alloys with thickness of 0.04 inches to 0.09 inches. The critical CTOA and the corresponding plane strain core height necessary to simulate through-the-thickness effects at the crack tip in an otherwise plane stress analysis, were determined from small laboratory specimens. Using these parameters, the CTOA fracture criterion was used to predict the behavior of middle crack tension specimens that were up to 40 inches wide, flat panels with riveted stiffeners and multiple-site damage cracks, 18-inch diameter pressurized cylinders, and full scale curved stiffened panels subjected to internal pressure and mechanical loads.

  5. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The following areas of NASA's responsibilities are examined: (1) the Space Transportation System (STS) operations and evolving program elements; (2) establishment of the Space Station program organization and issuance of requests for proposals to the aerospace industry; and (3) NASA's aircraft operations, including research and development flight programs for two advanced X-type aircraft.

  6. Aerospace Bibliography. Seventh Edition.

    ERIC Educational Resources Information Center

    Blashfield, Jean F., Comp.

    Provided for teachers and the general adult reader is an annotated and graded list of books and reference materials dealing with aerospace subjects. Only non-fiction books and pamphlets that need to be purchased from commercial or government sources are included. Free industrial materials and educational aids are not included because they tend to…

  7. Aerospace at Saint Francis.

    ERIC Educational Resources Information Center

    Aviation/Space, 1980

    1980-01-01

    Discusses an aviation/aerospace program as a science elective for 11th and 12th year students. This program is multi-faceted and addresses the needs of a wide variety of students. Its main objective is to present aviation and space sciences which will provide a good base for higher education in these areas. (SK)

  8. Structural ECM components in the premetastatic and metastatic niche.

    PubMed

    Høye, Anette M; Erler, Janine T

    2016-06-01

    The aim of this review is to give an overview of the extracellular matrix (ECM) components that are important for creating structural changes in the premetastatic and metastatic niche. The successful arrival and survival of cancer cells that have left the primary tumor and colonized distant sites depends on the new microenvironment they encounter. The primary tumor itself releases factors into the circulation that travel to distant organs and then initiate structural changes, both non-enzymatic and enzymatic, to create a favorable niche for the disseminating tumor cells. Therapeutic strategies aimed at targeting cell-ECM interactions may well be one of the best viable approaches to combat metastasis and thus improve patient care. PMID:27053524

  9. Detection of Component Failures for Smart Structure Control Systems

    NASA Astrophysics Data System (ADS)

    Okubo, Hiroshi

    Uncertainties in the dynamics model of a smart structure are often of significance due to model errors caused by parameter identification errors and reduced-order modeling of the system. Design of a model-based Failure Detection and Isolation (FDI) system for smart structures, therefore, needs careful consideration regarding robustness with respect to such model uncertainties. In this paper, we proposes a new method of robust fault detection that is insensitive to the disturbances caused by unknown modeling errors while it is highly sensitive to the component failures. The capability of the robust detection algorithm is examined for the sensor failure of a flexible smart beam control system. It is shown by numerical simulations that the proposed method suppresses the disturbances due to model errors and markedly improves the detection performance.

  10. Magnons in one-dimensional k-component Fibonacci structures

    SciTech Connect

    Costa, C. H.; Vasconcelos, M. S.

    2014-05-07

    We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: S{sub n}{sup (k)}=S{sub n−1}{sup (k)}S{sub n−k}{sup (k)} (n≥k=0,1,2,…), where S{sub n}{sup (k)} is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.

  11. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During 1997, the Aerospace Safety Advisory Panel (ASAP) continued its safety reviews of NASA's human space flight and aeronautics programs. Efforts were focused on those areas that the Panel believed held the greatest potential to impact safety. Continuing safe Space Shuttle operations and progress in the manufacture and testing of primary components for the International Space Station (ISS) were noteworthy. The Panel has continued to monitor the safety implications of the transition of Space Shuttle operations to the United Space Alliance (USA). One area being watched closely relates to the staffing levels and skill mix in both NASA and USA. Therefore, a section of this report is devoted to personnel and other related issues that are a result of this change in NASA's way of doing business for the Space Shuttle. Attention will continue to be paid to this important topic in subsequent reports. Even though the Panel's activities for 1997 were extensive, fewer specific recommendations were formulated than has been the case in recent years. This is indicative of the current generally good state of safety of NASA programs. The Panel does, however, have several longer term concerns that have yet to develop to the level of a specific recommendation. These are covered in the introductory material for each topic area in Section 11. In another departure from past submissions, this report does not contain individual findings and recommendations for the aeronautics programs. While the Panel devoted its usual efforts to examining NASA's aeronautic centers and programs, no specific recommendations were identified for inclusion in this report. In lieu of recommendations, a summary of the Panel's observations of NASA's safety efforts in aeronautics and future Panel areas of emphasis is provided. With profound sadness the Panel notes the passing of our Chairman, Paul M. Johnstone, on December 17, 1997, and our Staff Assistant, Ms. Patricia M. Harman, on October 5, 1997. Other

  12. Multidisciplinary aerospace design optimization: Survey of recent developments

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

    1995-01-01

    The increasing complexity of engineering systems has sparked increasing interest in multidisciplinary optimization (MDO). This paper presents a survey of recent publications in the field of aerospace where interest in MDO has been particularly intense. The two main challenges of MDO are computational expense and organizational complexity. Accordingly the survey is focussed on various ways different researchers use to deal with these challenges. The survey is organized by a breakdown of MDO into its conceptual components. Accordingly, the survey includes sections on Mathematical Modeling, Design-oriented Analysis, Approximation Concepts, Optimization Procedures, System Sensitivity, and Human Interface. With the authors' main expertise being in the structures area, the bulk of the references focus on the interaction of the structures discipline with other disciplines. In particular, two sections at the end focus on two such interactions that have recently been pursued with a particular vigor: Simultaneous Optimization of Structures and Aerodynamics, and Simultaneous Optimization of Structures Combined With Active Control.

  13. 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.

  14. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Ho, H. W.; Kurth, R. E.

    1991-01-01

    The work performed to develop composite load spectra (CLS) for the Space Shuttle Main Engine (SSME) using probabilistic methods. The three methods were implemented to be the engine system influence model. RASCAL was chosen to be the principal method as most component load models were implemented with the method. Validation of RASCAL was performed. High accuracy comparable to the Monte Carlo method can be obtained if a large enough bin size is used. Generic probabilistic models were developed and implemented for load calculations using the probabilistic methods discussed above. Each engine mission, either a real fighter or a test, has three mission phases: the engine start transient phase, the steady state phase, and the engine cut off transient phase. Power level and engine operating inlet conditions change during a mission. The load calculation module provides the steady-state and quasi-steady state calculation procedures with duty-cycle-data option. The quasi-steady state procedure is for engine transient phase calculations. In addition, a few generic probabilistic load models were also developed for specific conditions. These include the fixed transient spike model, the poison arrival transient spike model, and the rare event model. These generic probabilistic load models provide sufficient latitude for simulating loads with specific conditions. For SSME components, turbine blades, transfer ducts, LOX post, and the high pressure oxidizer turbopump (HPOTP) discharge duct were selected for application of the CLS program. They include static pressure loads and dynamic pressure loads for all four components, centrifugal force for the turbine blade, temperatures of thermal loads for all four components, and structural vibration loads for the ducts and LOX posts.

  15. An Assessment of the State-of-the-Art in the Design and Manufacturing of Large Composite Structures for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Shuart, Mark J.

    2001-01-01

    An assessment of the State-of-the-Art in the design and manufacturing of large composite structures has been conducted. The focus of the assessment is large structural components in commercial and military aircraft. Applications of composites are reviewed for commercial transport aircraft, general aviation aircraft, rotorcraft, and military aircraft.

  16. Aerospace applications of integer and combinatorial optimization

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Kincaid, R. K.

    1995-01-01

    Research supported by NASA Langley Research Center includes many applications of aerospace design optimization and is conducted by teams of applied mathematicians and aerospace engineers. This paper investigates the benefits from this combined expertise in solving combinatorial optimization problems. Applications range from the design of large space antennas to interior noise control. A typical problem, for example, seeks the optimal locations for vibration-damping devices on a large space structure and is expressed as a mixed/integer linear programming problem with more than 1500 design variables.

  17. Second Conference on NDE for Aerospace Requirements

    NASA Technical Reports Server (NTRS)

    Woodis, Kenneth W. (Compiler); Bryson, Craig C. (Compiler); Workman, Gary L. (Compiler)

    1990-01-01

    Nondestructive evaluation and inspection procedures must constantly improve rapidly in order to keep pace with corresponding advances being made in aerospace material and systems. In response to this need, the 1989 Conference was organized to provide a forum for discussion between the materials scientists, systems designers, and NDE engineers who produce current and future aerospace systems. It is anticipated that problems in current systems can be resolved more quickly and that new materials and structures can be designed and manufactured in such a way as to be more easily inspected and to perform reliably over the life cycle of the system.

  18. Wireless Sensing Opportunities for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Wilson, William; Atkinson, Gary

    2007-01-01

    Wireless sensors and sensor networks is an emerging technology area with many applications within the aerospace industry. Integrated vehicle health monitoring (IVHM) of aerospace vehicles is needed to ensure the safety of the crew and the vehicle, yet often high costs, weight, size and other constraints prevent the incorporation of instrumentation onto spacecraft. This paper presents a few of the areas such as IVHM, where new wireless sensing technology is needed on both existing vehicles as well as future spacecraft. From ground tests to inflatable structures to the International Space Station, many applications could receive benefits from small, low power, wireless sensors. This paper also highlights some of the challenges that need to overcome when implementing wireless sensor networks for aerospace vehicles.

  19. Machine intelligence and autonomy for aerospace systems

    NASA Technical Reports Server (NTRS)

    Heer, Ewald (Editor); Lum, Henry (Editor)

    1988-01-01

    The present volume discusses progress toward intelligent robot systems in aerospace applications, NASA Space Program automation and robotics efforts, the supervisory control of telerobotics in space, machine intelligence and crew/vehicle interfaces, expert-system terms and building tools, and knowledge-acquisition for autonomous systems. Also discussed are methods for validation of knowledge-based systems, a design methodology for knowledge-based management systems, knowledge-based simulation for aerospace systems, knowledge-based diagnosis, planning and scheduling methods in AI, the treatment of uncertainty in AI, vision-sensing techniques in aerospace applications, image-understanding techniques, tactile sensing for robots, distributed sensor integration, and the control of articulated and deformable space structures.

  20. Aerospace NESHAP: A collaborative approach to implementation

    SciTech Connect

    McAfee, M.; Lee, A.; Williamson, C.; Willenberg, J.

    1998-12-31

    The purpose of the Aerospace National Emission Standard for Hazardous Air Pollutants (NESHAP) is to minimize emissions of hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from major sources who manufacture or rework aerospace vehicles or components. The NESHAP requires emission reductions through implementation of work practices, application of slower evaporating solvents and coatings with low-HAP and low-VOC content, usage of high transfer efficiency spray equipment, and installation of high capture efficiency exhaust filtration for coatings containing metals. The rule also requires extensive monitoring, recordkeeping, and self-reporting to track compliance. For existing sources the rule becomes effective September 1,1998. Over the past year the Puget Sound Air Pollution Control Agency (PSAPCA) has worked with the Boeing Company and EPA to identify the requirements of the aerospace NESHAP, understand what it means in everyday practice, and develop an enforcement strategy for ensuring compliance. A workshop was held with aerospace manufacturers, local regulators, and EPA to discuss implementation of the rule. Issues regarding compliance efforts and determinations were openly discussed. Subsequent to the workshop, PSAPCA and the Boeing Company participated in several mock inspections to review facility compliance efforts before the rule became effective. Collaborative efforts also ensued to develop operating permit monitoring requirements. Aerospace NESHAP requirements were incorporated into these permits. There are still questions regarding compliance determinations that must be further discussed and resolved. But by using the collaborative approach and having regulators and sources working together, there is a process to work out answers and approaches that will lead to an increased mutual understanding of the aerospace NESHAP and eventual compliance with the standard.

  1. The 18th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Topics concerning aerospace mechanisms, their functional performance, and design specifications are presented. Discussed subjects include the design and development of release mechanisms, actuators, linear driver/rate controllers, antenna and appendage deployment systems, position control systems, and tracking mechanisms for antennas and solar arrays. Engine design, spaceborne experiments, and large space structure technology are also examined.

  2. Advanced lightweight alloys for aerospace applications

    NASA Astrophysics Data System (ADS)

    Frazier, William E.; Lee, Eui W.; Donnellan, Mary E.; Thompson, James J.

    1989-05-01

    The design requirements of the next generation of advanced aerospace vehicles and propulsion systems necessitate the development of structural materials with properties vastly superior to those which are currently achievable. Recognizing that each class of materials possesses its own unique set of advantages and disadvantages, the designers of tomorrow's aircraft must choose wisely from the plethora of available alloys.

  3. The 15th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Technological areas covered include: aerospace propulsion; aerodynamic devices; crew safety; space vehicle control; spacecraft deployment, positioning, and pointing; deployable antennas/reflectors; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activities on the space shuttle orbiter are also described.

  4. X-Aerogels for Structural Components and High Temperature Applications

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process

  5. Structure of the basal components of a bacterial transporter

    SciTech Connect

    Meisner, Jeffrey; Maehigashi, Tatsuya; André, Ingemar; Dunham, Christine M.; Moran, Jr., Charles P.

    2012-12-10

    Proteins SpoIIQ and SpoIIIAH interact through two membranes to connect the forespore and the mother cell during endospore development in the bacterium Bacillus subtilis. SpoIIIAH consists of a transmembrane segment and an extracellular domain with similarity to YscJ proteins. YscJ proteins form large multimeric rings that are the structural scaffolds for the assembly of type III secretion systems in Gram-negative bacteria. The predicted ring-forming motif of SpoIIIAH and other evidence led to the model that SpoIIQ and SpoIIIAH form the core components of a channel or transporter through which the mother cell nurtures forespore development. Therefore, to understand the roles of SpoIIIAH and SpoIIQ in channel formation, it is critical to determine whether SpoIIIAH adopts a ring-forming structural motif, and whether interaction of SpoIIIAH with SpoIIQ would preclude ring formation. We report a 2.8-{angstrom} resolution structure of a complex of SpoIIQ and SpoIIIAH. SpoIIIAH folds into the ring-building structural motif, and modeling shows that the structure of the SpoIIQ-SpoIIIAH complex is compatible with forming a symmetrical oligomer that is similar to those in type III systems. The inner diameters of the two most likely ring models are large enough to accommodate several copies of other integral membrane proteins. SpoIIQ contains a LytM domain, which is found in metalloendopeptidases, but lacks residues important for metalloprotease activity. Other LytM domains appear to be involved in protein-protein interactions. We found that the LytM domain of SpoIIQ contains an accessory region that interacts with SpoIIIAH.

  6. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr.

    1997-01-01

    This is the final report of the study "Aluminum-Based Materials for High Speed Aircraft" which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX without Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys, and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  7. A study of active thermography approaches for the non-destructive testing and evaluation of aerospace structures

    NASA Astrophysics Data System (ADS)

    Avdelidis, Nicolas P.; Ibarra-Castanedo, Clemente; Marioli-Riga, Zaira P.; Bendada, Abdelhakim; Maldague, Xavier P. V.

    2008-03-01

    The prerequisite for more competent and cost effective aircraft has led to the evolution of innovative testing and evaluation procedures. Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of an aircraft structure are essential to both reduce manufacturing costs and out of service time of aircraft due to maintenance. Nowadays, active - transient thermal NDT & E (i.e. thermography) is commonly used for assessing aircraft composites. This research work evaluates the potential of pulsed thermography (PT) and/or pulsed phase thermography (PPT) for assessing defects (i.e. impact damage and inclusions for delaminations) on GLARE and GLARE type composites. Finally, in the case of the detection of inserts - delaminations C-Scan ultrasonic testing was also used with the intention of providing supplementary results.

  8. Performance categorization of structures, systems & components and related issues

    SciTech Connect

    Hossain, Q.A.

    1993-09-30

    Provisions of DOE-STD-1021-93 on performance categorization of structures, systems and components (SSCs) subjected to natural phenomena hazards (NPHs) are summarized. The interrelationship among safety classification of SSCs (per DOE 6430.1A and DOE 5480.30), facility hazard categorization/classification (per DOE 5481.1B and DOE 5480.23), and NPH performance categorization of SSCs (per DOE 5480.28 and DOE-STD-1021-93) is discussed. The compatibility between the safety goals in the Department of Energy Safety Policy, SEN-35-91, and the numerical NPH performance goals of DOE 5480.28, as presented in UCRL-ID-12612 (draft), is examined.

  9. Induced radioactivity of LDEF materials and structural components

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Laird, C. E.; Fishman, G. J.; Parnell, T. A.; Camp, D. C.; Frederick, C. E.; Hurley, D. L.; Lindstrom, D. J.; Moss, C. E.; Reedy, R. C.; Reeves, J. H.; Smith, A. R.; Winn, W. G.; Benton, E. V.

    1996-01-01

    We present an overview of the Long Duration Exposure Facility (LDEF) induced activation measurements. The LDEF, which was gravity-gradient stabilized, was exposed to the low Earth orbit (LEO) radiation environment over a 5.8 year period. Retrieved activation samples and structural components from the spacecraft were analyzed with low and ultra-low background HPGe gamma spectrometry at several national facilities. This allowed a very sensitive measurement of long-lived radionuclides produced by proton- and neutron-induced reactions in the time-dependent, non-isotropic LEO environment. A summary of major findings from this study is given that consists of directionally dependent activation, depth profiles, thermal neutron activation, and surface beryllium-7 deposition from the upper atmosphere. We also describe a database of these measurements that has been prepared for use in testing radiation environmental models and spacecraft design.

  10. Induced radioactivity of LDEF materials and structural components.

    PubMed

    Harmon, B A; Laird, C E; Fishman, G J; Parnell, T A; Camp, D C; Frederick, C E; Hurley, D L; Lindstrom, D J; Moss, C E; Reedy, R C; Reeves, J H; Smith, A R; Winn, W G; Benton, E V

    1996-11-01

    We present an overview of the Long Duration Exposure Facility (LDEF) induced activation measurements. The LDEF, which was gravity-gradient stabilized, was exposed to the low Earth orbit (LEO) radiation environment over a 5.8 year period. Retrieved activation samples and structural components from the spacecraft were analyzed with low and ultra-low background HPGe gamma spectrometry at several national facilities. This allowed a very sensitive measurement of long-lived radionuclides produced by proton- and neutron-induced reactions in the time-dependent, non-isotropic LEO environment. A summary of major findings from this study is given that consists of directionally dependent activation, depth profiles, thermal neutron activation, and surface beryllium-7 deposition from the upper atmosphere. We also describe a database of these measurements that has been prepared for use in testing radiation environmental models and spacecraft design. PMID:11540519

  11. Applications of aerospace technology

    NASA Technical Reports Server (NTRS)

    Rouse, Doris J.

    1984-01-01

    The objective of the Research Triangle Institute Technology Transfer Team is to assist NASA in achieving widespread utilization of aerospace technology in terrestrial applications. Widespread utilization implies that the application of NASA technology is to benefit a significant sector of the economy and population of the Nation. This objective is best attained by stimulating the introduction of new or improved commercially available devices incorporating aerospace technology. A methodology is presented for the team's activities as an active transfer agent linking NASA Field Centers, industry associations, user groups, and the medical community. This methodology is designed to: (1) identify priority technology requirements in industry and medicine, (2) identify applicable NASA technology that represents an opportunity for a successful solution and commercial product, (3) obtain the early participation of industry in the transfer process, and (4) successfully develop a new product based on NASA technology.

  12. 3D printed components with ultrasonically arranged microscale structure

    NASA Astrophysics Data System (ADS)

    Llewellyn-Jones, Thomas M.; Drinkwater, Bruce W.; Trask, Richard S.

    2016-02-01

    This paper shows the first application of in situ manipulation of discontinuous fibrous structure mid-print, within a 3D printed polymeric composite architecture. Currently, rapid prototyping methods (fused filament fabrication, stereolithography) are gaining increasing popularity within the engineering commnity to build structural components. Unfortunately, the full potential of these components is limited by the mechanical properties of the materials used. The aim of this study is to create and demonstrate a novel method to instantaneously orient micro-scale glass fibres within a selectively cured photocurable resin system, using ultrasonic forces to align the fibres in the desired 3D architecture. To achieve this we have mounted a switchable, focused laser module on the carriage of a three-axis 3D printing stage, above an in-house ultrasonic alignment rig containing a mixture of photocurable resin and discontinuous 14 μm diameter glass fibre reinforcement(50 μm length). In our study, a suitable print speed of 20 mm s-1 was used, which is comparable to conventional additive layer techniques. We show the ability to construct in-plane orthogonally aligned sections printed side by side, where the precise orientation of the configurations is controlled by switching the ultrasonic standing wave profile mid-print. This approach permits the realisation of complex fibrous architectures within a 3D printed landscape. The versatile nature of the ultrasonic manipulation technique also permits a wide range of particle types (diameters, aspect ratios and functions) and architectures (in-plane, and out-plane) to be patterned, leading to the creation of a new generation of fibrous reinforced composites for 3D printing.

  13. 43rd Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A.

    2016-01-01

    The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Sponsored and organized by the Mechanisms Education Association, responsibility for hosting the AMS is shared by the National Aeronautics and Space Administration and Lockheed Martin Space Systems Company (LMSSC). Now in its 43rd symposium, the AMS continues to be well attended, attracting participants from both the U.S. and abroad. The 43rd AMS was held in Santa Clara, California on May 4, 5 and 6, 2016. During these three days, 42 papers were presented. Topics included payload and positioning mechanisms, components such as hinges and motors, CubeSats, tribology, and mechanism testing. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components. The high quality of this symposium is a result of the work of many people, and their efforts are gratefully acknowledged. This extends to the voluntary members of the symposium organizing committee representing the eight NASA field centers, LMSSC, and the European Space Agency. Appreciation is also extended to the session chairs, the authors, and particularly the personnel at ARC responsible for the symposium arrangements and the publication of these proceedings. A sincere thank you also goes to the symposium executive committee who is responsible for the year-to-year management of the AMS, including paper processing and preparation of the program. The use of trade names of manufacturers in this publication does not constitute an official endorsement of such products or manufacturers, either expressed or implied, by the National Aeronautics and Space Administration.

  14. Wiring for aerospace applications

    NASA Technical Reports Server (NTRS)

    Christian, J. L., Jr.; Dickman, J. E.; Bercaw, R. W.; Myers, I. T.; Hammoud, A. N.; Stavnes, M.; Evans, J.

    1992-01-01

    In this paper, the authors summarize the current state of knowledge of arc propagation in aerospace power wiring and efforts by the National Aeronautics and Space Administration (NASA) towards the understanding of the arc tracking phenomena in space environments. Recommendations will be made for additional testing. A database of the performance of commonly used insulating materials will be developed to support the design of advanced high power missions, such as Space Station Freedom and Lunar/Mars Exploration.

  15. Aerospace safety advisory panel

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report from the Aerospace Safety Advisory Panel (ASAP) contains findings, recommendations, and supporting material concerning safety issues with the space station program, the space shuttle program, aeronautics research, and other NASA programs. Section two presents findings and recommendations, section three presents supporting information, and appendices contain data about the panel membership, the NASA response to the March 1993 ASAP report, and a chronology of the panel's activities during the past year.

  16. Unmanned Aerospace Vehicle Workshop

    SciTech Connect

    Vitko, J. Jr.

    1995-04-01

    The Unmanned Aerospace Vehicle (UAV) Workshop concentrated on reviewing and refining the science experiments planned for the UAV Demonstration Flights (UDF) scheduled at the Oklahoma Cloud and Radiation Testbed (CART) in April 1994. These experiments were focused around the following sets of parameters: Clear sky, daylight; Clear-sky, night-to-day transition; Clear sky - improve/validate the accuracy of radiative fluxes derived from satellite-based measurements; Daylight, clouds of opportunity; and, Daylight, broken clouds.

  17. Role of the micro/macro structure of welds in crack nucleation and propagation in aerospace aluminum-lithium alloy

    NASA Technical Reports Server (NTRS)

    Talia, George E.

    1996-01-01

    Al-Li alloys offer the benefits of increased strength, elastic modulus and lower densities as compared to conventional aluminum alloys. Martin Marietta Laboratories has developed an Al-Li alloy designated 2195 which is designated for use in the cryogenic tanks of the space shuttle. The Variable Polarity Plasma Arc (VPPA) welding process is currently being used to produce these welds [1]. VPPA welding utilizes high temperature ionized gas (plasma) to transfer heat to the workpiece. An inert gas, such as Helium, is used to shield the active welding zone to prevent contamination of the molten base metal with surrounding reactive atmospheric gases. [1] In the Space Shuttle application, two passes of the arc are used to complete a butt-type weld. The pressure of the plasma stream is increased during the first pass to force the arc entirely through the material, a practice commonly referred to as keyholing. Molten metal forms on either side of the arc and surface tension draws this liquid together as the arc passes. 2319 Al alloy filler material may also be fed into the weld zone during this pass. During the second pass, the plasma stream pressure is reduced such that only partial penetration of the base material is obtained. Al 2319 filler material is added during this pass to yield a uniform, fully filled welded joint. This additional pass also acts to alter the grain structure of the weld zone to yield a higher strength joint.

  18. Role of the micro/macro structure of welds in crack nucleation and propagation in aerospace aluminum-lithium alloy

    SciTech Connect

    Talia, G.E.

    1996-02-01

    Al-Li alloys offer the benefits of increased strength, elastic modulus and lower densities as compared to conventional aluminum alloys. Martin Marietta Laboratories has developed an Al-Li alloy designated 2195 which is designated for use in the cryogenic tanks of the space shuttle. The Variable Polarity Plasma Arc (VPPA) welding process is currently being used to produce these welds. VPPA welding utilizes high temperature ionized gas (plasma) to transfer heat to the workpiece. An inert gas, such as Helium, is used to shield the active welding zone to prevent contamination of the molten base metal with surrounding reactive atmospheric gases. (1) In the Space Shuttle application, two passes of the arc are used to complete a butt-type weld. The pressure of the plasma stream is increased during the first pass to force the arc entirely through the material, a practice commonly referred to as keyholing. Molten metal forms on either side of the arc and surface tension draws this liquid together as the arc passes. 2319 Al alloy filler material may also be fed into the weld zone during this pass. During the second pass, the plasma stream pressure is reduced such that only partial penetration of the base material is obtained. Al 2319 filler material is added during this pass to yield a uniform, fully filled welded joint. This additional pass also acts to alter the grain structure of the weld zone to yield a higher strength joint.

  19. Structure and phase behavior in five-component microemulsions

    SciTech Connect

    Billman, J.F. ); Kaler, E.W. )

    1990-03-01

    Droplet-to-bicontinuous structure transitions in a family of five-component microemulsions formed with sodium 4-(1{prime}-heptylnonyl)benzenesulfonate, isobutyl alcohol, D{sub 2}O, sodium chloride, and alkanes with even carbon numbers from octane to hexadecane are probed by using small-angle neutron scattering, electrical conductivity, and NMR self-diffusion measurements. The phase behavior and structure of these microemulsions are intimately linked and depend on salinity and the chain length of the alkane. Both the range of salt concentration in which the three-phase region is observed and the range of microemulsion water volume fraction within the three-phase region decrease with decreasing alkane chain length. Further, the appearance of the three-phase region is preceded by droplet-to-bicontinuous transitions. Microemulsions not exhibiting three-phase regions become bicontinuous only when they contain equal amounts of oil and water. The coincidence of the so-called percolation thresholds as determined by using electrical conductivity and self-diffusion measurements shows that electrical conduction in a dispersion of water droplets occurs with the exchange of material between the droplets.

  20. Bonding and structure in dense multi-component molecular mixtures.

    PubMed

    Meyer, Edmund R; Ticknor, Christopher; Bethkenhagen, Mandy; Hamel, Sebastien; Redmer, Ronald; Kress, Joel D; Collins, Lee A

    2015-10-28

    We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10,000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systems engendered by variations in the concentration ratios. A basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers. PMID:26520533

  1. Bonding and structure in dense multi-component molecular mixtures

    DOE PAGESBeta

    Meyer, Edmund R.; Ticknor, Christopher; Bethkenhagen, Mandy; Hamel, Sebastien; Redmer, Ronald; Kress, Joel D.; Collins, Lee A.

    2015-10-30

    We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systemsmore » engendered by variations in the concentration ratios. As a result, a basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.« less

  2. Recognizing genes and other components of genomic structure

    SciTech Connect

    Burks, C. ); Myers, E. . Dept. of Computer Science); Stormo, G.D. . Dept. of Molecular, Cellular and Developmental Biology)

    1991-01-01

    The Aspen Center for Physics (ACP) sponsored a three-week workshop, with 26 scientists participating, from 28 May to 15 June, 1990. The workshop, entitled Recognizing Genes and Other Components of Genomic Structure, focussed on discussion of current needs and future strategies for developing the ability to identify and predict the presence of complex functional units on sequenced, but otherwise uncharacterized, genomic DNA. We addressed the need for computationally-based, automatic tools for synthesizing available data about individual consensus sequences and local compositional patterns into the composite objects (e.g., genes) that are -- as composite entities -- the true object of interest when scanning DNA sequences. The workshop was structured to promote sustained informal contact and exchange of expertise between molecular biologists, computer scientists, and mathematicians. No participant stayed for less than one week, and most attended for two or three weeks. Computers, software, and databases were available for use as electronic blackboards'' and as the basis for collaborative exploration of ideas being discussed and developed at the workshop. 23 refs., 2 tabs.

  3. Development and fabrication of structural components for a scramjet engine

    NASA Technical Reports Server (NTRS)

    Buchmann, O. A.

    1990-01-01

    A program broadly directed toward design and development of long-life (100 hours and 1,000 cycles with a goal of 1,000 hours and 10,000 cycles) hydrogen-cooled structures for application to scramjets is presented. Previous phases of the program resulted in an overall engine design and analytical and experimental characterization of selected candidate materials and concepts. The latter efforts indicated that the basic life goals for the program can be reached with available means. The main objective of this effort was an integrated, experimental evaluation of the results of the previous program phases. The fuel injection strut was selected for this purpose, including fabrication development and fabrication of a full-scale strut. Testing of the completed strut was to be performed in a NASA-Langley wind tunnel. In addition, conceptual designs were formulated for a heat transfer test unit and a flat panel structural test unit. Tooling and fabrication procedures required to fabricate the strut were developed, and fabrication and delivery to NASA of all strut components, including major subassemblies, were completed.

  4. Bonding and structure in dense multi-component molecular mixtures

    SciTech Connect

    Meyer, Edmund R.; Ticknor, Christopher; Bethkenhagen, Mandy; Hamel, Sebastien; Redmer, Ronald; Kress, Joel D.; Collins, Lee A.

    2015-10-30

    We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systems engendered by variations in the concentration ratios. As a result, a basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.

  5. NASA's activities in the conservation of strategic aerospace materials

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1980-01-01

    The primary objective of the Conservation of Strategic Aerospace Materials (COSAM) Program is to help reduce the dependence of the United States aerospace industry on strategic metals by providing the materials technology needed to minimize the strategic metal content of critical aerospace components with prime emphasis on components for gas turbine engines. Initial emphasis was placed in the area of strategic element substinction. Specifically, the role of cobalt in nickel base and cobalt base superalloys vital to the aerospace industry is being examined in great detail by means of cooperative university-industry-government research efforts. Investigations are underway in the area of "new classes" of alloys. Specifically, a study was undertaken to investigate the mechanical and physical properties of intermetallics that contain a minimum of the strategic metals. Current plans for the much larger COSAM Program are also presented.

  6. Sputtering and ion plating for aerospace applications

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    Sputtering and ion plating technologies are reviewed in terms of their potential and present uses in the aerospace industry. Sputtering offers great universality and flexibility in depositing any material or in the synthesis of new ones. The sputter deposition process has two areas of interest: thin film and fabrication technology. Thin film sputtering technology is primarily used for aerospace mechanical components to reduce friction, wear, erosion, corrosion, high temperature oxidation, diffusion and fatigue, and also to sputter-construct temperature and strain sensors for aircraft engines. Sputter fabrication is used in intricate aircraft component manufacturing. Ion plating applications are discussed in terms of the high energy evaporant flux and the high throwing power. Excellent adherence and 3 dimensional coverage are the primary attributes of this technology.

  7. Quantifying Ecosystem Structural Components with Highly Portable Lidar

    NASA Astrophysics Data System (ADS)

    Schaaf, C.; Paynter, I.; Peri, F.; Saenz, E. J.; Genest, D.; Strahler, A. H.; Li, Z.

    2015-12-01

    Terrestrial laser scanners (TLS), which utilize light detection and ranging (lidar) have demonstrated the ability to produce accurate reconstructions of ecosystems, including spatially complex systems such as forests. Reconstructions at the object or plot scale can be used to interpret or simulate satellite observations, particularly for lidar instruments such as those involved in the forthcoming GEDI and ICESat 2 missions. The Compact Biomass Lidar (CBL) is a TLS optimized for portability and scanning speed, developed and operated by University of Massachusetts Boston. This 905nm wavelength scanner achieves an angular resolution of 0.25 degrees at a rate of 33 seconds per scan. The rapid scanning of the CBL and similar highly portable TLS improve acquisition of 3D surfaces such as canopy height models and digital elevation models derived from point clouds. This is due to the ability to capture additional scanning points within the window of temporal stability for the ecosystem, mitigating the rapid loss of information density associated with distance and occlusion. Utilizing terrestrial lidar in tandem with airborne lidar profiles vertically distributed structural components of ecosystems, such as the canopy of forests. We will present 3D surfaces documenting the growth of vegetation species including the invasive Phragmites australis over the 2015 growing season at Plum Island Long Term Ecological Research sites, derived from CBL. Additionally we will show vertical structure profiles from voxelization analyses in tropical forest (La Selva, Costa Rica) and temperate forest (Harvard Forest, MA, USA). We will discuss and present results from emerging point cloud reconstruction methods, including the Quantitative Structure Model (QSM) for tree modeling, and their implications particularly for GEDI-related calibration and validation studies.

  8. Cyanobacterial Two-Component Proteins: Structure, Diversity, Distribution, and Evolution†

    PubMed Central

    Ashby, Mark K.; Houmard, Jean

    2006-01-01

    A survey of the already characterized and potential two-component protein sequences that exist in the nine complete and seven partially annotated cyanobacterial genome sequences available (as of May 2005) showed that the cyanobacteria possess a much larger repertoire of such proteins than most other bacteria. By analysis of the domain structure of the 1,171 potential histidine kinases, response regulators, and hybrid kinases, many various arrangements of about thirty different modules could be distinguished. The number of two-component proteins is related in part to genome size but also to the variety of physiological properties and ecophysiologies of the different strains. Groups of orthologues were defined, only a few of which have representatives with known physiological functions. Based on comparisons with the proposed phylogenetic relationships between the strains, the orthology groups show that (i) a few genes, some of them clustered on the genome, have been conserved by all species, suggesting their very ancient origin and an essential role for the corresponding proteins, and (ii) duplications, fusions, gene losses, insertions, and deletions, as well as domain shuffling, occurred during evolution, leading to the extant repertoire. These mechanisms are put in perspective with the different genetic properties that cyanobacteria have to achieve genome plasticity. This review is designed to serve as a basis for orienting further research aimed at defining the most ancient regulatory mechanisms and understanding how evolution worked to select and keep the most appropriate systems for cyanobacteria to develop in the quite different environments that they have successfully colonized. PMID:16760311

  9. Rapid adhesive bonding and field repair of aerospace materials

    NASA Technical Reports Server (NTRS)

    Stein, B. A.

    1985-01-01

    Adhesive bonding in the aerospace industry typically utilizes autoclaves or presses which have considerable thermal mass. As a consequence, the rates of heatup and cooldown of the bonded parts are limited and the total time and cost of the bonding process are often relatively high. Many of the adhesives themselves do not inherently require long processing times. Bonding could be performed rapidly if the heat was concentrated in the bond lines or at least in the adherends. Rapid Adhesive Bonding concepts are developed to utilize induction heating techniques to provide heat directly to the bond line and/or adherends without heating the entire structure, supports, and fixtures of a bonding assembly. Bonding times for specimens can be cut by a factor of 10 to 100 compared to standard press or autoclave bonding. The development of Rapid Adhesive Bonding for lap shear specimens (per ASTM D1002 and D3163), for aerospace panel or component bonding, and for field repair needs of metallic and advanced fiber reinforced polymeric-matrix composite structures is reviewed. Equipment and procedures are described for bonding and repairing thin sheets, simple geometries, and honeycomb core panels.

  10. High temperature arc-track resistant aerospace insulation

    NASA Technical Reports Server (NTRS)

    Dorogy, William

    1994-01-01

    The topics are presented in viewgraph form and include the following: high temperature aerospace insulation; Foster-Miller approach to develop a 300 C rated, arc-track resistant aerospace insulation; advantages and disadvantages of key structural features; summary goals and achievements of the phase 1 program; performance goals for selected materials; materials under evaluation; molecular structures of candidate polymers; candidate polymer properties; film properties; and a detailed program plan.

  11. CHEMICAL STRUCTURES IN COAL: GEOCHEMICAL EVIDENCE FOR THE PRESENCE OF MIXED STRUCTURAL COMPONENTS.

    USGS Publications Warehouse

    Hatcher, P.G.; Breger, I.A.; Maciel, G.E.; Szeverenyi, N.M.

    1983-01-01

    The purpose of this paper is to summarize work on the chemical structural components of coal, comparing them with their possible plant precursors in modern peat. Solid-state **1**3C nuclear magnetic resonance (NMR), infrared spectroscopy (IR), elemental analysis and, in some cases, individual compound analyses formed the bases for these comparisons.

  12. The Aerospace Environment. Aerospace Education I. Instructor Handbook.

    ERIC Educational Resources Information Center

    Air Univ., Maxwell AFB, AL. Junior Reserve Office Training Corps.

    This publication provides guidelines for teachers using the textbook entitled "Aerospace Environment," published in the Aerospace Education I series. Major categories included in each chapter are objectives, behavioral objectives, suggested outline, orientation, suggested key points, instructional aids, projects, and further reading. Background…

  13. NASA-UVA Light Aerospace Alloy and Structures Technology Program (LA2ST). Supplement: Research on Materials for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Gangloff, Richard P.; Starke, Edgar A., Jr.

    1997-01-01

    This report documents the progress achieved over the past 6 to 12 months on four graduate student projects conducted within the NASA-UVA Light Aerospace Alloy and Structures Technology Program. These studies were aimed specifically at light metallic alloy issues relevant to the High Speed Civil Transport. Research on Hydrogen-Enhanced Fracture of High-Strength Titanium Alloy Sheet refined successfully the high resolution R-curve method necessary to characterize initiation and growth fracture toughnesses. For solution treated and aged Low Cost Beta without hydrogen precharging, fracture is by ductile transgranular processes at 25 C, but standardized initiation toughnesses are somewhat low and crack extension is resolved at still lower K-levels. This fracture resistance is degraded substantially, by between 700 and 1000 wppm of dissolved hydrogen, and a fracture mode change is affected. The surface oxide on P-titanium alloys hinders hydrogen uptake and complicates the electrochemical introduction of low hydrogen concentrations that are critical to applications of these alloys. Ti-15-3 sheet was obtained for study during the next reporting period. Research on Mechanisms of deformation and Fracture in High-Strength Titanium Alloys is examining the microstructure and fatigue resistance of very thin sheet. Aging experiments on 0. 14 mm thick (0.0055 inch) foil show microstructural agility that may be used to enhance fatigue performance. Fatigue testing of Ti-15-3 sheet has begun. The effects of various thermo-mechanical processing regimens on mechanical properties will be examined and deformation modes identified. Research on the Effect of Texture and Precipitates on Mechanical Property Anisotropy of Al-Cu-Mg-X and Al-Cu alloys demonstrated that models predict a minor influence of stress-induced alignment of Phi, caused by the application of a tensile stress during aging, on the yield stress anisotropy of both modified AA2519 and a model Al-Cu binary alloy. This project

  14. Structural materials for ITER in-vessel component design

    NASA Astrophysics Data System (ADS)

    Kalinin, G.; Gauster, W.; Matera, R.; Tavassoli, A.-A. F.; Rowcliffe, A.; Fabritsiev, S.; Kawamura, H.

    1996-10-01

    The materials proposed for ITER in-vessel components have to exhibit adequate performance for the operating lifetime of the reactor or for specified replacement intervals. Estimates show that maximum irradiation dose to be up to 5-7 dpa (for 1 MWa/m 2 in the basic performance phase (BPP)) within a temperature range from 20 to 300°C. Austenitic SS 316LN-ITER Grade was defined as a reference option for the vacuum vessel, blanket, primary wall, pipe lines and divertor body. Conventional technologies and mill products are proposed for blanket, back plate and manifold manufacturing. HIPing is proposed as a reference manufacturing method for the primary wall and blanket and as an option for the divertor body. The existing data show that mechanical properties of HIPed SS are no worse than those of forged 316LN SS. Irradiation will result in property changes. Minimum ductility has been observed after irradiation in an approximate temperature range between 250 and 350°C, for doses of 5-10 dpa. In spite of radiation-induced changes in tensile deformation behavior, the fracture remains ductile. Irradiation assisted corrosion cracking is a concern for high doses of irradiation and at high temperatures. Re-welding is one of the critical issues because of the need to replace failed components. It is also being considered for the replacement of shielding blanket modules by breeding modules after the BPP. Estimates of radiation damage at the locations for re-welding show that the dose will not exceed 0.05 dpa (with He generation of 1 appm) for the manifold and 0.01 dpa (with He generation 0.1 appm) for the back plate for the BPP of ITER operation. Existing experimental data show that these levels will not result in property changes for SS; however, neutron irradiation and He generation promote crack formation in the heat affected zone during welding. Cu based alloys, DS-Cu (Glidcop A125) and PHCu CuCrZr bronze) are proposed as a structural materials for high heat flux

  15. Materials Selection for Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Arnold, Steven M.; Cebon, David; Ashby, Mike

    2012-01-01

    A systematic design-oriented, five-step approach to material selection is described: 1) establishing design requirements, 2) material screening, 3) ranking, 4) researching specific candidates and 5) applying specific cultural constraints to the selection process. At the core of this approach is the definition performance indices (i.e., particular combinations of material properties that embody the performance of a given component) in conjunction with material property charts. These material selection charts, which plot one property against another, are introduced and shown to provide a powerful graphical environment wherein one can apply and analyze quantitative selection criteria, such as those captured in performance indices, and make trade-offs between conflicting objectives. Finding a material with a high value of these indices maximizes the performance of the component. Two specific examples pertaining to aerospace (engine blades and pressure vessels) are examined, both at room temperature and elevated temperature (where time-dependent effects are important) to demonstrate the methodology. The discussion then turns to engineered/hybrid materials and how these can be effectively tailored to fill in holes in the material property space, so as to enable innovation and increases in performance as compared to monolithic materials. Finally, a brief discussion is presented on managing the data needed for materials selection, including collection, analysis, deployment, and maintenance issues.

  16. Limitless Horizons: Careers in Aerospace.

    ERIC Educational Resources Information Center

    Lewis, Mary H.

    This is a manual for acquainting students with pertinent information relating to career choices in aerospace science, engineering, and technology. The first chapter presents information about the aerospace industry by describing disciplines typical of this industry. The National Aeronautics and Space Administration's (NASA) classification system…

  17. Limitless Horizons. Careers in Aerospace

    NASA Technical Reports Server (NTRS)

    Lewis, M. H.

    1980-01-01

    A manual is presented for use by counselors in career guidance programs. Pertinent information is provided on choices open in aerospace sciences, engineering, and technology. Accredited institutions awarding degrees in pertinent areas are listed as well as additional sources of aerospace career information. NASA's role and fields of interest are emphasized.

  18. Aerospace Activities and Language Development

    ERIC Educational Resources Information Center

    Jones, Robert M.; Piper, Martha

    1975-01-01

    Describes how science activities can be used to stimulate language development in the elementary grades. Two aerospace activities are described involving liquid nitrogen and the launching of a weather balloon which integrate aerospace interests into the development of language skills. (BR)

  19. Lewis Structures Technology, 1988. Volume 2: Structural Mechanics

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Lewis Structures Div. performs and disseminates results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practitioners of structural engineering mechanics beyond the aerospace arena. The engineering community was familiarized with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

  20. National Aerospace Plane Thermal Development. (Latest Citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The bibliography contains citations concerning thermal properties of the National Aerospace Plane (NASP). Analysis of thermal stress, and methods for determining thermal effects on the plane's supersonic structure are discussed. The citations also review temperature extremes that the vehicle is likely to encounter. (Contains 50-250 citations and includes a subject term index and title list.)

  1. National Aerospace Plane Thermal Development. (Latest citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The bibliography contains citations concerning thermal properties of the National Aerospace Plane (NASP). Analysis of thermal stress, and methods for determining thermal effects on the plane's supersonic structure are discussed. The citations also review temperature extremes that the vehicle is likely to encounter.

  2. NASA/DoD Aerospace Knowledge Diffusion Research Project. XXVI - The relationship between technology policy and scientific and technical information within the U.S. and Japanese aerospace industries

    NASA Technical Reports Server (NTRS)

    Pinelli, Thomas E.; Barclay, Rebecca O.; Lahr, Tom; Hoetker, Glenn

    1993-01-01

    Government technology policy has nurtured the growth of the aerospace industry, which is vital to both the U.S. and Japanese economies. Japanese technology policy differs significantly from U.S. technology policy, however, particularly with respect to the production, transfer, and use of scientific and technical information (STI). In this paper, we discuss the unique position of the aerospace industry in the U.S. and Japan, U.S. and Japanese aerospace policy, and the role of STI in the process of aerospace innovation. The information-seeking behaviors of U.S. and Japanese aerospace engineers and scientists are compared. The authors advocate the development of innovation-adoption technology and STI policy goals for U.S. aerospace and the inclusion of an aerospace knowledge diffusion transfer system with an 'active' component for scanning and acquiring foreign aerospace technology and STI.

  3. Explosion welding and cutting in aerospace engineering

    NASA Astrophysics Data System (ADS)

    Volgin, L. A.; Koroteev, A. Ia.; Malakovich, A. P.; Petushkov, V. G.; Sitalo, V. G.; Novikov, V. K.

    The paper presents the results of works of the E.O. Paton Electric Welding Institute and other Soviet organizations on the development of technology for explosion-welding of multilayer transition pieces and pipes used in the manufacture of aerospace products. Equipment and accessories used for this technology are described; in particular, a powerful explosion chamber of a tubular structure for up to 200 kg of explosives is presented. Information is also given about linear explosion separation devices.

  4. Study on application of aerospace technology to improve surgical implants

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.; Youngblood, J. L.

    1982-01-01

    The areas where aerospace technology could be used to improve the reliability and performance of metallic, orthopedic implants was assessed. Specifically, comparisons were made of material controls, design approaches, analytical methods and inspection approaches being used in the implant industry with hardware for the aerospace industries. Several areas for possible improvement were noted such as increased use of finite element stress analysis and fracture control programs on devices where the needs exist for maximum reliability and high structural performance.

  5. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Aerospace Safety Advisory Panel (ASAP) provided oversight on the safety aspects of many NASA programs. In addition, ASAP undertook three special studies. At the request of the Administrator, the panel assessed the requirements for an assured crew return vehicle (ACRV) for the space station and reviewed the organization of the safety and mission quality function within NASA. At the behest of Congress, the panel formed an independent, ad hoc working group to examine the safety and reliability of the space shuttle main engine. Section 2 presents findings and recommendations. Section 3 consists of information in support of these findings and recommendations. Appendices A, B, C, and D, respectively, cover the panel membership, the NASA response to the findings and recommendations in the March 1992 report, a chronology of the panel's activities during the reporting period, and the entire ACRV study report.

  6. Aerospace in the future

    NASA Technical Reports Server (NTRS)

    Mccarthy, J. F., Jr.

    1980-01-01

    National research and technology trends are introduced in the environment of accelerating change. NASA and the federal budget are discussed. The U.S. energy dependence on foreign oil, the increasing oil costs, and the U.S. petroleum use by class are presented. The $10 billion aerospace industry positive contribution to the U.S. balance of trade of 1979 is given as an indicator of the positive contribution of NASA in research to industry. The research work of the NASA Lewis Research Center in the areas of space, aeronautics, and energy is discussed as a team effort of government, the areas of space, aeronautics, and energy is discussed as a team effort of government, industry, universities, and business to maintain U.S. world leadership in advanced technology.

  7. Aerospace Human Factors

    NASA Technical Reports Server (NTRS)

    Jordan, Kevin

    1999-01-01

    The following contains the final report on the activities related to the Cooperative Agreement between the human factors research group at NASA Ames Research Center and the Psychology Department at San Jose State University. The participating NASA Ames division has been, as the organization has changed, the Aerospace Human Factors Research Division (ASHFRD and Code FL), the Flight Management and Human Factors Research Division (Code AF), and the Human Factors Research and Technology Division (Code IH). The inclusive dates for the report are November 1, 1984 to January 31, 1999. Throughout the years, approximately 170 persons worked on the cooperative agreements in one capacity or another. The Cooperative Agreement provided for research personnel to collaborate with senior scientists in ongoing NASA ARC research. Finally, many post-MA/MS and post-doctoral personnel contributed to the projects. It is worth noting that 10 former cooperative agreement personnel were hired into civil service positions directly from the agreements.

  8. Aerospace and military

    SciTech Connect

    Adam, J.A.; Esch, K

    1990-01-01

    This article reviews military and aerospace developments of 1989. The Voyager spacecraft returned astounding imagery from Neptune, sophisticated sensors were launched to explore Venus and Jupiter, and another craft went into earth orbit to explore cosmic rays, while a huge telescope is to be launched early in 1990. The U.S. space shuttle redesign was completed and access to space has become no longer purely a governmental enterprise. In the military realm, events within the Soviet bloc, such as the Berlin Wall's destruction, have popularized arms control. Several big treaties could be signed within the year. Massive troop, equipment, and budget reductions are being considered, along with a halt or delay of major new weapons systems. For new missions, the U.S. military is retreating to its role of a century ago - patrolling the nation's borders, this time against narcotics traffickers.

  9. Dynamics of aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Schmidt, David K.

    1991-01-01

    The focus of this research was to address the modeling, including model reduction, of flexible aerospace vehicles, with special emphasis on models used in dynamic analysis and/or guidance and control system design. In the modeling, it is critical that the key aspects of the system being modeled be captured in the model. In this work, therefore, aspects of the vehicle dynamics critical to control design were important. In this regard, fundamental contributions were made in the areas of stability robustness analysis techniques, model reduction techniques, and literal approximations for key dynamic characteristics of flexible vehicles. All these areas are related. In the development of a model, approximations are always involved, so control systems designed using these models must be robust against uncertainties in these models.

  10. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This report covers the activities of the Aerospace Safety Advisory Panel (ASAP) for calendar year 1998-a year of sharp contrasts and significant successes at NASA. The year opened with the announcement of large workforce cutbacks. The slip in the schedule for launching the International Space Station (ISS) created a 5-month hiatus in Space Shuttle launches. This slack period ended with the successful and highly publicized launch of the STS-95 mission. As the year closed, ISS assembly began with the successful orbiting and joining of the Functional Cargo Block (FGB), Zarya, from Russia and the Unity Node from the United States. Throughout the year, the Panel maintained its scrutiny of NASAs safety processes. Of particular interest were the potential effects on safety of workforce reductions and the continued transition of functions to the Space Flight Operations Contractor. Attention was also given to the risk management plans of the Aero-Space Technology programs, including the X-33, X-34, and X-38. Overall, the Panel concluded that safety is well served for the present. The picture is not as clear for the future. Cutbacks have limited the depth of talent available. In many cases, technical specialties are "one deep." The extended hiring freeze has resulted in an older workforce that will inevitably suffer significant departures from retirements in the near future. The resulting "brain drain" could represent a future safety risk unless appropriate succession planning is started expeditiously. This and other topics are covered in the section addressing workforce. In the case of the Space Shuttle, beneficial and mandatory safety and operational upgrades are being delayed because of a lack of sufficient present funding. Likewise, the ISS has little flexibility to begin long lead-time items for upgrades or contingency planning.

  11. An Assessment of the State-of-the-Art in the Design and Manufacturing of Large Composite Structures for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Starnes, James H., Jr.; Shuart, Mark J.

    2001-01-01

    The results of an assessment of the state-of-the-art in the design and manufacturing of large composite structures are described. The focus of the assessment is on the use of polymeric matrix composite materials for large airframe structural components. such as those in commercial and military aircraft and space transportation vehicles. Applications of composite materials for large commercial transport aircraft, general aviation aircraft, rotorcraft, military aircraft. and unmanned rocket launch vehicles are reviewed. The results of the assessment of the state-of-the-art include a summary of lessons learned, examples of current practice, and an assessment of advanced technologies under development. The results of the assessment conclude with an evaluation of the future technology challenges associated with applications of composite materials to the primary structures of commercial transport aircraft and advanced space transportation vehicles.

  12. Computational simulation of coupled material degradation processes for probabilistic lifetime strength of aerospace materials

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Bast, Callie C.

    1992-01-01

    The research included ongoing development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primative variables. These primative variable may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above described constitutive equation using actual experimental materials data together with linear regression of that data, thereby predicting values for the empirical material constraints for each effect or primative variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from the open literature for materials typically of interest to those studying aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology.

  13. Structure of multi-component/multi-Yukawa mixtures

    NASA Astrophysics Data System (ADS)

    Blum, L.; Arias, M.

    2006-09-01

    Recent small angle scattering experiments reveal new peaks in the structure function S(k) of colloidal systems (Liu et al 2005 J. Chem. Phys. 122 044507), in a region that was inaccessible with older instruments. It has been increasingly evident that a single (or double) Yukawa MSA-closure cannot account for these observations, and three or more terms are needed. On the other hand the MSA is not sufficiently accurate (Broccio et al 2005 Preprint); more accurate theories such as the HNC have been tried. But while the MSA is asymptotically exact at high densities (Rosenfield and Blum 1986 J. Chem. Phys. 85 1556), it does not satisfy the low density asymptotics. This has been corrected in the soft MSA (Blum et al 1972 J. Chem. Phys. 56 5197, Narten et al 1974 J. Chem. Phys. 60 3378) by adding exponential type terms. The results compared to experiment and simulation for liquid sodium by Rahman and Paskin (as shown in Blum et al 1972 J. Chem. Phys. 56 5197) are remarkably good. We use here a general closure of the Ornstein-Zernike equation, which is not necessarily the MSA closure (Blum and Hernando 2001 Condensed Matter Theories vol 16 ed Hernandez and Clark (New York: Nova) p 411). \\begin{equation} \\fl c_{ij}(r)=\\sum_{n=1}^{M}{\\cal{K}}_{ij}^{(n)}\\rme^{-z_{n}r}/r\\tqs {\\cal{K}}_{ij}^{(n)}=K^{(n)}\\delta_{i}^{(n)}\\delta_{j}^{(n)}\\tqs r\\geq \\sigma_{ij} \\label{eq1} \\end{equation} with the boundary condition for gij(r) = 0 for r<=σij. This general closure of the Ornstein-Zernike equation will go well beyond the MSA since it has been tested by Monte Carlo simulation for tetrahedral water (Blum et al 1999 Physica A 265 396), toroidal ion channels (Enriquez and Blum 2005 Mol. Phys. 103 3201) and polyelectrolytes (Blum and Bernard 2004 Proc. Int. School of Physics Enrico Fermi, Course CLV vol 155, ed Mallamace and Stanley (Amsterdam: IOS Press) p 335). For this closure we get for the Laplace transform of the pair correlation function an explicitly symmetric result

  14. Developing IVHM Requirements for Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Rajamani, Ravi; Saxena, Abhinav; Kramer, Frank; Augustin, Mike; Schroeder, John B.; Goebel, Kai; Shao, Ginger; Roychoudhury, Indranil; Lin, Wei

    2013-01-01

    The term Integrated Vehicle Health Management (IVHM) describes a set of capabilities that enable sustainable and safe operation of components and subsystems within aerospace platforms. However, very little guidance exists for the systems engineering aspects of design with IVHM in mind. It is probably because of this that designers have to use knowledge picked up exclusively by experience rather than by established process. This motivated a group of leading IVHM practitioners within the aerospace industry under the aegis of SAE's HM-1 technical committee to author a document that hopes to give working engineers and program managers clear guidance on all the elements of IVHM that they need to consider before designing a system. This proposed recommended practice (ARP6883 [1]) will describe all the steps of requirements generation and management as it applies to IVHM systems, and demonstrate these with a "real-world" example related to designing a landing gear system. The team hopes that this paper and presentation will help start a dialog with the larger aerospace community and that the feedback can be used to improve the ARP and subsequently the practice of IVHM from a systems engineering point-of-view.

  15. Structure and compositional studies of multi-component nanoparticles

    NASA Astrophysics Data System (ADS)

    Malyavanatham, Gokul

    The laser ablation of microparticle (LAM) process was used to study nanoparticles of multi-component materials. The production process utilized laser ablation of a continuously flowing aerosol of micron-sized particles under a gas ambient. An aerosol generator entrained microparticles into a gas flow and directed them through a nozzle into a laser interaction cell. After plasma breakdown, the shock wave propagated through the microparticles and the nanoparticles condensed behind this shockwave. Two methods were developed to collect nanoparticles; the first method used supersonic impaction on substrates at room temperature to enable direct writing of thick films and the second method used electric fields to deflect and collect charged, individual nanoparticles. Two methods for generating multi-component nanostructured materials were studied. The first method involved feeding single-phase microparticles containing the desired composition. Lead Zirconate Titanate (PZT) microparticles were used to generate nanoparticles that were then impacted onto substrates to produce thick films. Quality, morphology, crystallization and composition variations of these thick films were analyzed using material characterization techniques. Segregation of elements and an overall deficiency in Zr and Ti were observed in the deposited thick films as a result of the agglomerated state of the PZT microparticles. However, the analysis for this material system was complicated by the presence of multiple compounds. To develop a further understanding of how segregation occurs in multi-component systems during the LAM process, a second method for generating multi-component nanoparticles by feeding mixtures of single component microparticles was studied. Nanoparticles generated by ablation of Cu and Au microparticle mixtures were collected electrostatically and analyzed. Interactions between exploding microparticles resulted in condensation of nanoparticles that were non-equilibrium solid

  16. Aerospace Applications of Optimization under Uncertainty

    NASA Technical Reports Server (NTRS)

    Padula, Sharon; Gumbert, Clyde; Li, Wu

    2003-01-01

    The Multidisciplinary Optimization (MDO) Branch at NASA Langley Research Center develops new methods and investigates opportunities for applying optimization to aerospace vehicle design. This paper describes MDO Branch experiences with three applications of optimization under uncertainty: (1) improved impact dynamics for airframes, (2) transonic airfoil optimization for low drag, and (3) coupled aerodynamic/structures optimization of a 3-D wing. For each case, a brief overview of the problem and references to previous publications are provided. The three cases are aerospace examples of the challenges and opportunities presented by optimization under uncertainty. The present paper will illustrate a variety of needs for this technology, summarize promising methods, and uncover fruitful areas for new research.

  17. Aerospace Applications of Optimization under Uncertainty

    NASA Technical Reports Server (NTRS)

    Padula, Sharon; Gumbert, Clyde; Li, Wu

    2006-01-01

    The Multidisciplinary Optimization (MDO) Branch at NASA Langley Research Center develops new methods and investigates opportunities for applying optimization to aerospace vehicle design. This paper describes MDO Branch experiences with three applications of optimization under uncertainty: (1) improved impact dynamics for airframes, (2) transonic airfoil optimization for low drag, and (3) coupled aerodynamic/structures optimization of a 3-D wing. For each case, a brief overview of the problem and references to previous publications are provided. The three cases are aerospace examples of the challenges and opportunities presented by optimization under uncertainty. The present paper will illustrate a variety of needs for this technology, summarize promising methods, and uncover fruitful areas for new research.

  18. Aerospace management techniques: Commercial and governmental applications

    NASA Technical Reports Server (NTRS)

    Milliken, J. G.; Morrison, E. J.

    1971-01-01

    A guidebook for managers and administrators is presented as a source of useful information on new management methods in business, industry, and government. The major topics discussed include: actual and potential applications of aerospace management techniques to commercial and governmental organizations; aerospace management techniques and their use within the aerospace sector; and the aerospace sector's application of innovative management techniques.

  19. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.

    1987-01-01

    The objective of this program is to develop generic load models to simulate the composite load spectra (CLS) that are induced in space propulsion system components representative of the space shuttle main engines (SSME). These models are being developed through describing individual component loads with an appropriate mix of deterministic and state-of-the-art probabilistic models that are related to key generic variables. Combinations of the individual loads are used to synthesize the composite loads spectra. A second approach for developing the composite loads spectra load model simulation, the option portion of the contract will develop coupled models which combine the individual load models. Statistically varying coefficients of the physical models will be used to obtain the composite load spectra.

  20. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Annual Report of the Aerospace Safety Advisory Panel (ASAP) presents results of activities during calendar year 2001. The year was marked by significant achievements in the Space Shuttle and International Space Station (ISS) programs and encouraging accomplishments by the Aerospace Technology Enterprise. Unfortunately, there were also disquieting mishaps with the X-43, a LearJet, and a wind tunnel. Each mishap was analyzed in an orderly process to ascertain causes and derive lessons learned. Both these accomplishments and the responses to the mishaps led the Panel to conclude that safety and risk management is currently being well served within NASA. NASA's operations evidence high levels of safety consciousness and sincere efforts to place safety foremost. Nevertheless, the Panel's safety concerns have never been greater. This dichotomy has arisen because the focus of most NASA programs has been directed toward program survival rather than effective life cycle planning. Last year's Annual Report focused on the need for NASA to adopt a realistically long planning horizon for the aging Space Shuttle so that safety would not erode. NASA's response to the report concurred with this finding. Nevertheless, there has been a greater emphasis on current operations to the apparent detriment of long-term planning. Budget cutbacks and shifts in priorities have severely limited the resources available to the Space Shuttle and ISS for application to risk-reduction and life-extension efforts. As a result, funds originally intended for long-term safety-related activities have been used for operations. Thus, while safety continues to be well served at present, the basis for future safety has eroded. Section II of this report develops this theme in more detail and presents several important, overarching findings and recommendations that apply to many if not all of NASA's programs. Section III of the report presents other significant findings, recommendations and supporting

  1. Norwegian Aerospace Activities: an Overview

    NASA Technical Reports Server (NTRS)

    Arnesen, T. (Editor); Rosenberg, G. (Editor)

    1986-01-01

    Excerpts from a Governmental Investigation concerning Norwegian participation in the European Space Organization (ESA) is presented. The implications and advantages of such a move and a suggestion for the reorganization of Norwegian Aerospace activity is given.

  2. The FASST Aerospace Student Forum

    ERIC Educational Resources Information Center

    David, Leonard

    1976-01-01

    Describes a three-day Forum for the Advancement of Students in Science and Technology (FASST), at which students from 20 colleges and universities and six Soviet students discussed the application of aerospace technology to the problems of society. (MLH)

  3. AeroSpace Days 2013

    NASA Video Gallery

    At the eighth annual AeroSpace Days, first mom in space, Astronaut AnnaFisher, and Sen. Louise Lucas, interacted with students from Mack BennJr. Elementary School in Suffolk, Va. through NASA’s...

  4. Heat transfer in aerospace propulsion

    NASA Technical Reports Server (NTRS)

    Simoneau, Robert J.; Hendricks, Robert C.; Gladden, Herbert J.

    1988-01-01

    Presented is an overview of heat transfer related research in support of aerospace propulsion, particularly as seen from the perspective of the NASA Lewis Research Center. Aerospace propulsion is defined to cover the full spectrum from conventional aircraft power plants through the Aerospace Plane to space propulsion. The conventional subsonic/supersonic aircraft arena, whether commercial or military, relies on the turbine engine. A key characteristic of turbine engines is that they involve fundamentally unsteady flows which must be properly treated. Space propulsion is characterized by very demanding performance requirements which frequently push systems to their limits and demand tailored designs. The hypersonic flight propulsion systems are subject to severe heat loads and the engine and airframe are truly one entity. The impact of the special demands of each of these aerospace propulsion systems on heat transfer is explored.

  5. Ball Aerospace AMSD Progress Update

    NASA Technical Reports Server (NTRS)

    Blair, Mark; Brown, Robert; Chaney, David; Lightsey, Paul; Russell, J. Kevin (Technical Monitor)

    2002-01-01

    The current status of the Advanced Mirror System Demonstrator program being performed by Ball Aerospace is presented. The hexagonal low-areal density Beryllium mirror blank has been fabricated and undergoing polishing at the time of this presentation.

  6. 32nd Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Walker, S. W. (Compiler); Boesiger, Edward A. (Compiler)

    1998-01-01

    The proceedings of the 32nd Aerospace Mechanism Symposium are reported. NASA John F. Kennedy Space Center (KSC) hosted the symposium that was held at the Hilton Oceanfront Hotel in Cocoa Beach, Florida on May 13-15, 1998. The symposium was cosponsored by Lockheed Martin Missiles and Space and the Aerospace Mechanisms Symposium Committee. During these days, 28 papers were presented. Topics included robotics, deployment mechanisms, bearing, actuators, scanners, boom and antenna release, and test equipment.

  7. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This report provides findings, conclusions and recommendations regarding the National Space Transportation System (NSTS), the Space Station Freedom Program (SSFP), aeronautical projects and other areas of NASA activities. The main focus of the Aerospace Safety Advisory Panel (ASAP) during 1988 has been monitoring and advising NASA and its contractors on the Space Transportation System (STS) recovery program. NASA efforts have restored the flight program with a much better management organization, safety and quality assurance organizations, and management communication system. The NASA National Space Transportation System (NSTS) organization in conjunction with its prime contractors should be encouraged to continue development and incorporation of appropriate design and operational improvements which will further reduce risk. The data from each Shuttle flight should be used to determine if affordable design and/or operational improvements could further increase safety. The review of Critical Items (CILs), Failure Mode Effects and Analyses (FMEAs) and Hazard Analyses (HAs) after the Challenger accident has given the program a massive data base with which to establish a formal program with prioritized changes.

  8. Aerospace Safety Advisory Panel

    NASA Astrophysics Data System (ADS)

    1989-03-01

    This report provides findings, conclusions and recommendations regarding the National Space Transportation System (NSTS), the Space Station Freedom Program (SSFP), aeronautical projects and other areas of NASA activities. The main focus of the Aerospace Safety Advisory Panel (ASAP) during 1988 has been monitoring and advising NASA and its contractors on the Space Transportation System (STS) recovery program. NASA efforts have restored the flight program with a much better management organization, safety and quality assurance organizations, and management communication system. The NASA National Space Transportation System (NSTS) organization in conjunction with its prime contractors should be encouraged to continue development and incorporation of appropriate design and operational improvements which will further reduce risk. The data from each Shuttle flight should be used to determine if affordable design and/or operational improvements could further increase safety. The review of Critical Items (CILs), Failure Mode Effects and Analyses (FMEAs) and Hazard Analyses (HAs) after the Challenger accident has given the program a massive data base with which to establish a formal program with prioritized changes.

  9. Detection of bondline delaminations in multilayer structures with lossy components

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Winfree, William P.; Smith, B. T.; Heyman, Joseph H.

    1988-01-01

    The detection of bondline delaminations in multilayer structures using ultrasonic reflection techniques is a generic problem in adhesively bonded composite structures such as the Space Shuttles's Solid Rocket Motors (SRM). Standard pulse echo ultrasonic techniques do not perform well for a composite resonator composed of a resonant layer combined with attenuating layers. Excessive ringing in the resonant layer tends to mask internal echoes emanating from the attenuating layers. The SRM is made up of a resonant steel layer backed by layers of adhesive, rubber, liner and fuel, which are ultrasonically attenuating. The structure's response is modeled as a lossy ultrasonic transmission line. The model predicts that the acoustic response of the system is sensitive to delaminations at the interior bondlines in a few narrow frequency bands. These predictions are verified by measurements on a fabricated system. Successful imaging of internal delaminations is sensitive to proper selection of the interrogating frequency. Images of fabricated bondline delaminations are presented based on these studies.

  10. Development of Methodologies for the Estimation of Thermal Properties Associated with Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Scott, Elaine P.

    1996-01-01

    A thermal stress analysis is an important aspect in the design of aerospace structures and vehicles such as the High Speed Civil Transport (HSCT) at the National Aeronautics and Space Administration Langley Research Center (NASA-LaRC). These structures are complex and are often composed of numerous components fabricated from a variety of different materials. The thermal loads on these structures induce temperature variations within the structure, which in turn result in the development of thermal stresses. Therefore, a thermal stress analysis requires knowledge of the temperature distributions within the structures which consequently necessitates the need for accurate knowledge of the thermal properties, boundary conditions and thermal interface conditions associated with the structural materials. The goal of this proposed multi-year research effort was to develop estimation methodologies for the determination of the thermal properties and interface conditions associated with aerospace vehicles. Specific objectives focused on the development and implementation of optimal experimental design strategies and methodologies for the estimation of thermal properties associated with simple composite and honeycomb structures. The strategy used in this multi-year research effort was to first develop methodologies for relatively simple systems and then systematically modify these methodologies to analyze complex structures. This can be thought of as a building block approach. This strategy was intended to promote maximum usability of the resulting estimation procedure by NASA-LARC researchers through the design of in-house experimentation procedures and through the use of an existing general purpose finite element software.

  11. Heat-stressed structural components in combustion-engine design

    NASA Technical Reports Server (NTRS)

    Kraemer, Otto

    1938-01-01

    Heated structural parts alter their shape. Anything which hinders free heat expansion will give rise to heat stresses. Design rules are thus obtained for the heated walls themselves as well as for the adjoining parts. An important guiding principle is that of designing the heat-conducting walls as thin as possible.

  12. Release strategies for making transferable semiconductor structures, devices and device components

    DOEpatents

    Rogers, John A; Nuzzo, Ralph G; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J

    2014-11-25

    Provided are methods for making a device or device component by providing a multilayer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  13. Release strategies for making transferable semiconductor structures, devices and device components

    DOEpatents

    Rogers, John A.; Nuzzo, Ralph G.; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J.

    2016-05-24

    Provided are methods for making a device or device component by providing a multi layer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  14. Release strategies for making transferable semiconductor structures, devices and device components

    DOEpatents

    Rogers, John A.; Nuzzo, Ralph G.; Meitl, Matthew; Ko, Heung Cho; Yoon, Jongseung; Menard, Etienne; Baca, Alfred J.

    2011-04-26

    Provided are methods for making a device or device component by providing a multilayer structure having a plurality of functional layers and a plurality of release layers and releasing the functional layers from the multilayer structure by separating one or more of the release layers to generate a plurality of transferable structures. The transferable structures are printed onto a device substrate or device component supported by a device substrate. The methods and systems provide means for making high-quality and low-cost photovoltaic devices, transferable semiconductor structures, (opto-)electronic devices and device components.

  15. Engineering in the 21st century. [aerospace technology prospects

    NASA Technical Reports Server (NTRS)

    Mccarthy, J. F., Jr.

    1978-01-01

    A description is presented of the nature of the aerospace technology system that might be expected by the 21st century from a reasonable evolution of the current resources and capabilities. An aerospace employment outlook is provided. The years 1977 and 1978 seem to be marking the beginning of a period of stability and moderate growth in the aerospace industry. Aerospace research and development employment increased to 70,000 in 1977 and is now occupying a near-constant 18% share of the total research and development work force. The changing job environment is considered along with the future of aerospace education. It is found that one trend is toward a more interdisciplinary education. Most trend setters in engineering education recognize that the really challenging engineering problems invariably require the judicious exercise of several disciplines for their solution. Some future trends in aerospace technology are discussed. By the year 2000 space technology will have achieved major advances in four areas, including management of information, transportation, space structures, and energy.

  16. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Kurth, R. E.; Ho, H.

    1991-01-01

    The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen posts and system ducting. The first approach will consist of using state of the art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The second approach will consist of developing coupled models for composite load spectra simulation which combine the deterministic models for composite load dynamic, acoustic, high pressure, and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data.

  17. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Kurth, R. E.; Ho, H.

    1991-01-01

    The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen (LOX) posts and system ducting. These models will be developed using two independent approaches. The first approach consists of using state-of-the-art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The methodology required to combine the various individual load simulation models (hot-gas dynamic, vibrations, instantaneous position, centrifugal field, etc.) into composite load spectra simulation models will be developed under this program. A computer code incorporating the various individual and composite load spectra models will be developed to construct the specific load model desired. The second approach, which is covered under the options portion of the contract, will consist of developing coupled models for composite load spectra simulation which combine the (deterministic) models for composite load dynamic, acoustic, high-pressure and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data. This report covers the efforts of the third year of the contract. The overall program status is that the turbine blade loads have been completed and implemented. The transfer duct loads are defined and are being implemented. The thermal loads for all components are defined and coding is being developed. A dynamic pressure load model is under development. The parallel work on the probabilistic methodology is essentially completed. The overall effort is being

  18. An Ongoing Role for Structural Sarcomeric Components in Maintaining Drosophila melanogaster Muscle Function and Structure

    PubMed Central

    Perkins, Alexander D.; Tanentzapf, Guy

    2014-01-01

    Animal muscles must maintain their function while bearing substantial mechanical loads. How muscles withstand persistent mechanical strain is presently not well understood. The basic unit of muscle is the sarcomere, which is primarily composed of cytoskeletal proteins. We hypothesized that cytoskeletal protein turnover is required to maintain muscle function. Using the flight muscles of Drosophila melanogaster, we confirmed that the sarcomeric cytoskeleton undergoes turnover throughout adult life. To uncover which cytoskeletal components are required to maintain adult muscle function, we performed an RNAi-mediated knockdown screen targeting the entire fly cytoskeleton and associated proteins. Gene knockdown was restricted to adult flies and muscle function was analyzed with behavioural assays. Here we analyze the results of that screen and characterize the specific muscle maintenance role for several hits. The screen identified 46 genes required for muscle maintenance: 40 of which had no previously known role in this process. Bioinformatic analysis highlighted the structural sarcomeric proteins as a candidate group for further analysis. Detailed confocal and electron microscopic analysis showed that while muscle architecture was maintained after candidate gene knockdown, sarcomere length was disrupted. Specifically, we found that ongoing synthesis and turnover of the key sarcomere structural components Projectin, Myosin and Actin are required to maintain correct sarcomere length and thin filament length. Our results provide in vivo evidence of adult muscle protein turnover and uncover specific functional defects associated with reduced expression of a subset of cytoskeletal proteins in the adult animal. PMID:24915196

  19. Design-Load Basis for LANL Structures, Systems, and Components

    SciTech Connect

    I. Cuesta

    2004-09-01

    This document supports the recommendations in the Los Alamos National Laboratory (LANL) Engineering Standard Manual (ESM), Chapter 5--Structural providing the basis for the loads, analysis procedures, and codes to be used in the ESM. It also provides the justification for eliminating the loads to be considered in design, and evidence that the design basis loads are appropriate and consistent with the graded approach required by the Department of Energy (DOE) Code of Federal Regulation Nuclear Safety Management, 10, Part 830. This document focuses on (1) the primary and secondary natural phenomena hazards listed in DOE-G-420.1-2, Appendix C, (2) additional loads not related to natural phenomena hazards, and (3) the design loads on structures during construction.

  20. Optimal glass-ceramic structures: Components of giant mirror telescopes

    NASA Technical Reports Server (NTRS)

    Eschenauer, Hans A.

    1990-01-01

    Detailed investigations are carried out on optimal glass-ceramic mirror structures of terrestrial space technology (optical telescopes). In order to find an optimum design, a nonlinear multi-criteria optimization problem is formulated. 'Minimum deformation' at 'minimum weight' are selected as contradictory objectives, and a set of further constraints (quilting effect, optical faults etc.) is defined and included. A special result of the investigations is described.

  1. The Effects of Polyunsaturated Lipid Components on bilayer Structure

    NASA Astrophysics Data System (ADS)

    Pramudya, Y.; Kiss, A.; Nguyen, Lam T.; Yuan, J.; Hirst, Linda S.

    2007-03-01

    Polyunsaturated fatty acids (PUFAs), such as DHA (Docosahexanoic Acid) and AA (Alphalinoleic Acid) have been the focus of much research attention in recent years, due to their apparent health benefits and effects on cell physiology. They are found in a variety of biological membranes and have been implicated with lipid raft formation and possible function, particularly in the retinal rod cells and the central nervous system. In this work lipid bilayer structure has been investigated in lipid mixtures, incorporating polyunsaturated fatty acid moieties. The structural effects of increasing concentrations of both symmetric and asymmetric PUFA materials on the bilayer structure are investigated via synchrotron x-ray diffraction on solution samples. We observe bilayer spacings to increase with the percentage of unsaturated fatty acid lipid in the membrane, whilst the degree of ordering significantly decreases. In fact above 20% of fatty acid, well defined bilayers are no longer observed to form. Evidence of phase separation can be clearly seen from these x-ray results and in combination with AFM measurements.

  2. Design component method for sensitivity analysis of built-up structures

    NASA Technical Reports Server (NTRS)

    Choi, Kyung K.; Seong, Hwai G.

    1986-01-01

    A 'design component method' that provides a unified and systematic organization of design sensitivity analysis for built-up structures is developed and implemented. Both conventional design variables, such as thickness and cross-sectional area, and shape design variables of components of built-up structures are considered. It is shown that design of components of built-up structures can be characterized and system design sensitivity expressions obtained by simply adding contributions from each component. The method leads to a systematic organization of computations for design sensitivity analysis that is similar to the way in which computations are organized within a finite element code.

  3. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This report covers the activities of the Aerospace Safety Advisory Panel (ASAP) for calendar year 1998-a year of sharp contrasts and significant successes at NASA. The year opened with the announcement of large workforce cutbacks. The slip in the schedule for launching the International Space Station (ISS) created a five-month hiatus in Space Shuttle launches. This slack period ended with the successful and highly publicized launch of the STS-95 mission. As the year closed, ISS assembly began with the successful orbiting and joining of the Functional Cargo Block (FGB), Zarya, from Russia and the Unity Node from the United States. Throughout the year, the Panel maintained its scrutiny of NASA's safety processes. Of particular interest were the potential effects on safety of workforce reductions and the continued transition of functions to the Space Flight Operations Contractor. Attention was also given to the risk management plans of the Aero-Space Technology programs, including the X-33, X-34, and X-38. Overall, the Panel concluded that safety is well served for the present. The picture is not as clear for the future. Cutbacks have limited the depth of talent available. In many cases, technical specialties are 'one deep.' The extended hiring freeze has resulted in an older workforce that will inevitably suffer significant departures from retirements in the near future. The resulting 'brain drain' could represent a future safety risk unless appropriate succession planning is started expeditiously. This and other topics are covered in the section addressing workforce. The major NASA programs are also limited in their ability to plan property for the future. This is of particular concern for the Space Shuttle and ISS because these programs are scheduled to operate well into the next century. In the case of the Space Shuttle, beneficial and mandatory safety and operational upgrades are being delayed because of a lack of sufficient present funding. Likewise, the ISS has

  4. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This annual report is based on the activities of the Aerospace Safety Advisory Panel in calendar year 2000. During this year, the construction of the International Space Station (ISS) moved into high gear. The launch of the Russian Service Module was followed by three Space Shuttle construction and logistics flights and the deployment of the Expedition One crew. Continuous habitation of the ISS has begun. To date, both the ISS and Space Shuttle programs have met or exceeded most of their flight objectives. In spite of the intensity of these efforts, it is clear that safety was always placed ahead of cost and schedule. This safety consciousness permitted the Panel to devote more of its efforts to examining the long-term picture. With ISS construction accelerating, demands on the Space Shuttle will increase. While Russian Soyuz and Progress spacecraft will make some flights, the Space Shuttle remains the primary vehicle to sustain the ISS and all other U.S. activities that require humans in space. Development of a next generation, human-rated vehicle has slowed due to a variety of technological problems and the absence of an approach that can accomplish the task significantly better than the Space Shuttle. Moreover, even if a viable design were currently available, the realities of funding and development cycles suggest that it would take many years to bring it to fruition. Thus, it is inescapable that for the foreseeable future the Space Shuttle will be the only human-rated vehicle available to the U.S. space program for support of the ISS and other missions requiring humans. Use of the Space Shuttle will extend well beyond current planning, and is likely to continue for the life of the ISS.

  5. 78 FR 19541 - Proposed Revision to Design of Structures, Components, Equipment and Systems

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-01

    ... published in the Federal Register (FR) on March 1, 2013 (78 FR 13911), that announced the request for comments on the proposed revisions in Chapter 3, ``Design of Structures, Components, Equipment, and Systems... COMMISSION Proposed Revision to Design of Structures, Components, Equipment and Systems AGENCY:...

  6. 78 FR 15755 - Proposed Revision to Design of Structures, Components, Equipment and Systems; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ... March 1, 2013 (41 FR 13911), that announced the solicitation for comments of the proposed revision in Chapter 3, ``Design of Structures, Components, Equipment, and Systems'' and is soliciting public comment... COMMISSION Proposed Revision to Design of Structures, Components, Equipment and Systems; Correction...

  7. Design procedures for fiber composite structural components: Rods, columns and beam columns

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1983-01-01

    Step by step procedures are described which are used to design structural components (rods, columns, and beam columns) subjected to steady state mechanical loads and hydrothermal environments. Illustrative examples are presented for structural components designed for static tensile and compressive loads, and fatigue as well as for moisture and temperature effects. Each example is set up as a sample design illustrating the detailed steps that are used to design similar components.

  8. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Kurth, R. E.; Ho, H.

    1986-01-01

    A multiyear program is performed with the objective to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen (LOX) posts. Progress of the first year's effort includes completion of a sufficient portion of each task -- probabilistic models, code development, validation, and an initial operational code. This code has from its inception an expert system philosophy that could be added to throughout the program and in the future. The initial operational code is only applicable to turbine blade type loadings. The probabilistic model included in the operational code has fitting routines for loads that utilize a modified Discrete Probabilistic Distribution termed RASCAL, a barrier crossing method and a Monte Carlo method. An initial load model was developed by Battelle that is currently used for the slowly varying duty cycle type loading. The intent is to use the model and related codes essentially in the current form for all loads that are based on measured or calculated data that have followed a slowly varying profile.

  9. Flight-service evaluation of composite structural components

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1973-01-01

    A review of programs aimed at flight-service evaluation of composite materials in various applications is presented. These flight-service programs are expected to continue for up to 5 years and include selective reinforcement of an airplane center wing box a helicopter tail cone, and composite replacements for commercial aircraft spoilers and fairings. These longtime flight-service programs will help provide the necessary information required by commercial airlines to commit advanced composites to aircraft structures with confidence. Results of these programs will provide information concerning the stability of composite materials when subjected to various flight environments.

  10. Probabilistic Structural Analysis Methods (PSAM) for select space propulsion system components, part 2

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The technical effort and computer code enhancements performed during the sixth year of the Probabilistic Structural Analysis Methods program are summarized. Various capabilities are described to probabilistically combine structural response and structural resistance to compute component reliability. A library of structural resistance models is implemented in the Numerical Evaluations of Stochastic Structures Under Stress (NESSUS) code that included fatigue, fracture, creep, multi-factor interaction, and other important effects. In addition, a user interface was developed for user-defined resistance models. An accurate and efficient reliability method was developed and was successfully implemented in the NESSUS code to compute component reliability based on user-selected response and resistance models. A risk module was developed to compute component risk with respect to cost, performance, or user-defined criteria. The new component risk assessment capabilities were validated and demonstrated using several examples. Various supporting methodologies were also developed in support of component risk assessment.

  11. Electron microscopic examination of wastewater biofilm formation and structural components.

    PubMed Central

    Eighmy, T T; Maratea, D; Bishop, P L

    1983-01-01

    This research documents in situ wastewater biofilm formation, structure, and physiochemical properties as revealed by scanning and transmission electron microscopy. Cationized ferritin was used to label anionic sites of the biofilm glycocalyx for viewing in thin section. Wastewater biofilm formation paralleled the processes involved in marine biofilm formation. Scanning electron microscopy revealed a dramatic increase in cell colonization and growth over a 144-h period. Constituents included a variety of actively dividing morphological types. Many of the colonizing bacteria were flagellated. Filaments were seen after primary colonization of the surface. Transmission electron microscopy revealed a dominant gram-negative cell wall structure in the biofilm constituents. At least three types of glycocalyces were observed. The predominant glycocalyx possessed interstices and was densely labeled with cationized ferritin. Two of the glycocalyces appeared to mediate biofilm adhesion to the substratum. The results suggest that the predominant glycocalyx of this thin wastewater biofilm serves, in part, to: (i) enclose the bacteria in a matrix and anchor the biofilm to the substratum and (ii) provide an extensive surface area with polyanionic properties. Images PMID:6881965

  12. Secondary aerospace batteries and battery materials: A bibliography, 1969 - 1974

    NASA Technical Reports Server (NTRS)

    Mcdermott, P.; Halpert, G.; Ekpanyaskun, S.; Nche, P.

    1976-01-01

    This annotated bibliography on the subject of secondary aerospace battery materials and related physical and electrochemical processes was compiled from references to journal articles published between 1969 and 1974. A total of 332 citations are arranged in chronological order under journal titles. Indices by system and component, techniques and processes, and author are included.

  13. Computer Architecture. (Latest Citations from the Aerospace Database)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The bibliography contains citations concerning research and development in the field of computer architecture. Design of computer systems, microcomputer components, and digital networks are among the topics discussed. Multimicroprocessor system performance, software development, and aerospace avionics applications are also included. (Contains 50-250 citations and includes a subject term index and title list.)

  14. Ceramic Integration Technologies for Energy and Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay; Asthana, Ralph N.

    2007-01-01

    Robust and affordable integration technologies for advanced ceramics are required to improve the performance, reliability, efficiency, and durability of components, devices, and systems based on them in a wide variety of energy, aerospace, and environmental applications. Many thermochemical and thermomechanical factors including joint design, analysis, and optimization must be considered in integration of similar and dissimilar material systems.

  15. Silicon carbide tritium permeation barrier for steel structural components.

    SciTech Connect

    Causey, Rion A.; Garde, Joseph Maurico; Buchenauer, Dean A.; Calderoni, Pattrick; Holschuh, Thomas, Jr.; Youchison, Dennis Lee; Wright, Matt; Kolasinski, Robert D.

    2010-09-01

    Chemical vapor deposited (CVD) silicon carbide (SiC) has superior resistance to tritium permeation even after irradiation. Prior work has shown Ultrametfoam to be forgiving when bonded to substrates with large CTE differences. The technical objectives are: (1) Evaluate foams of vanadium, niobium and molybdenum metals and SiC for CTE mitigation between a dense SiC barrier and steel structure; (2) Thermostructural modeling of SiC TPB/Ultramet foam/ferritic steel architecture; (3) Evaluate deuterium permeation of chemical vapor deposited (CVD) SiC; (4) D testing involved construction of a new higher temperature (> 1000 C) permeation testing system and development of improved sealing techniques; (5) Fabricate prototype tube similar to that shown with dimensions of 7cm {theta} and 35cm long; and (6) Tritium and hermeticity testing of prototype tube.

  16. Smart Sensors Assess Structural Health

    NASA Technical Reports Server (NTRS)

    2010-01-01

    NASA frequently inspects launch vehicles, fuel tanks, and other components for structural damage. To perform quick evaluation and monitoring, the Agency pursues the development of structural health monitoring systems. In 2001, Acellent Technologies Inc., of Sunnyvale, California, received Small Business Innovation Research (SBIR) funding from Marshall Space Flight Center to develop a hybrid Stanford Multi-Actuator Receiver Transduction (SMART) Layer for aerospace vehicles and structures. As a result, Acellent expanded the technology's capability and now sells it to aerospace and automotive companies; construction, energy, and utility companies; and the defense, space, transportation, and energy industries for structural condition monitoring, damage detection, crack growth monitoring, and other applications.

  17. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This report presents the results of the Aerospace Safety Advisory Panel (ASAP) activities during 2002. The format of the report has been modified to capture a long-term perspective. Section II is new and highlights the Panel's view of NASA's safety progress during the year. Section III contains the pivotal safety issues facing NASA in the coming year. Section IV includes the program area findings and recommendations. The Panel has been asked by the Administrator to perform several special studies this year, and the resulting white papers appear in Appendix C. The year has been filled with significant achievements for NASA in both successful Space Shuttle operations and International Space Station (ISS) construction. Throughout the year, safety has been first and foremost in spite of many changes throughout the Agency. The relocation of the Orbiter Major Modifications (OMMs) from California to Kennedy Space Center (KSC) appears very successful. The transition of responsibilities for program management of the Space Shuttle and ISS programs from Johnson Space Center (JSC) to NASA Headquarters went smoothly. The decision to extend the life of the Space Shuttle as the primary NASA vehicle for access to space is viewed by the Panel as a prudent one. With the appropriate investments in safety improvements, in maintenance, in preserving appropriate inventories of spare parts, and in infrastructure, the Space Shuttle can provide safe and reliable support for the ISS for the foreseeable future. Indications of an aging Space Shuttle fleet occurred on more than one occasion this year. Several flaws went undetected in the early prelaunch tests and inspections. In all but one case, the problems were found prior to launch. These incidents were all handled properly and with safety as the guiding principle. Indeed, launches were postponed until the problems were fully understood and mitigating action could be taken. These incidents do, however, indicate the need to analyze the

  18. Vertical distribution of structural components in corn stover

    SciTech Connect

    Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.; Cantrell, Keri B.; Archer, David W.; Wienhold, Brian J.; Varvel, Gary E.; Laird, David A.; Baker, John; Ochsner, Tyson E.; Novak, Jeff M.; Halvorson, Ardell D.; Arriaga, Francisco; Lightle, David T.; Hoover, Amber; Emerson, Rachel; Barbour, Nancy W.

    2014-11-17

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg⁻¹, but with an alkalinity measure of 0.83 g MJ⁻¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha⁻¹, but it would be only 1000 L ha⁻¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  19. Vertical distribution of structural components in corn stover

    SciTech Connect

    Jane M. F. Johnson; Douglas L. Karlen; Garold L. Gresham; Keri B. Cantrell; David W. Archer; Brian J. Wienhold; Gary E. Varvel; David A. Laird; John Baker; Tyson E. Ochsner; Jeff M. Novak; Ardell D. Halvorson; Francisco Arriaga; David T. Lightle; Amber Hoover; Rachel Emerson; Nancy W. Barbour

    2014-11-01

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the ear averaged 16.3 ± 0.40 MJ kg?¹, but with an alkalinity measure of 0.83 g MJ?¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha?¹, but it would be only 1000 L ha?¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.

  20. Vertical distribution of structural components in corn stover

    DOE PAGESBeta

    Johnson, Jane M. F.; Karlen, Douglas L.; Gresham, Garold L.; Cantrell, Keri B.; Archer, David W.; Wienhold, Brian J.; Varvel, Gary E.; Laird, David A.; Baker, John; Ochsner, Tyson E.; et al

    2014-11-17

    In the United States, corn (Zea mays L.) stover has been targeted for second generation fuel production and other bio-products. Our objective was to characterize sugar and structural composition as a function of vertical distribution of corn stover (leaves and stalk) that was sampled at physiological maturity and about three weeks later from multiple USA locations. A small subset of samples was assessed for thermochemical composition. Concentrations of lignin, glucan, and xylan were about 10% greater at grain harvest than at physiological maturity, but harvestable biomass was about 25% less due to stalk breakage. Gross heating density above the earmore » averaged 16.3 ± 0.40 MJ kg⁻¹, but with an alkalinity measure of 0.83 g MJ⁻¹, slagging is likely to occur during gasification. Assuming a stover harvest height of 10 cm, the estimated ethanol yield would be >2500 L ha⁻¹, but it would be only 1000 L ha⁻¹ if stover harvest was restricted to the material from above the primary ear. Vertical composition of corn stover is relatively uniform; thus, decision on cutting height may be driven by agronomic, economic and environmental considerations.« less

  1. The structural components of music perception. A functional anatomical study.

    PubMed

    Platel, H; Price, C; Baron, J C; Wise, R; Lambert, J; Frackowiak, R S; Lechevalier, B; Eustache, F

    1997-02-01

    This work explores the cerebral structures involved in the appreciation of music. We studied six young healthy subjects (right handed, French, without musical talent), using a high resolution PET device (CTI 953B) and 15O-labelled water. In three tasks, we studied the effects of selective attention to pitch, timbre and rhythm; a final task studied semantic familiarity with tunes (considered as divided attention for pitch and rhythm). These four tasks were performed on the same material (a tape consisting of 30 randomly arranged sequences of notes). We selected a paradigm, without a reference task, to compare the activations produced by attention to different parameters of the same stimulus. We expected that the activations recorded during each task would differ according to the differences in cognitive operations. We found activations preferentially in the left hemisphere for familiarity, pitch tasks and rhythm, and in the right hemisphere for the timbre task. The familiarity task activated the left inferior frontal gyrus, Brodmann area (BA) 47, and superior temporal gyrus (in its anterior part, BA 22). These activations presumably represent lexico-semantic access to melodic representations. In the pitch task, activations were observed in the left cuneus/precuneus (BA 18/19). These results were unexpected and we interpret them as reflecting a visual mental imagery strategy employed to carry out this task. The rhythm task activated left inferior Broca's area (BA 44/6), with extention into the neighbouring insula, suggesting a role for this cerebral region in the processing of sequential sounds. PMID:9117371

  2. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    Research in the basic composition, characteristics, and processng science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to problems. Detailed descriptions of the progress achieved in the various component parts of his program are presented.

  3. Guidelines for Design and Analysis of Large, Brittle Spacecraft Components

    NASA Technical Reports Server (NTRS)

    Robinson, E. Y.

    1993-01-01

    There were two related parts to this work. The first, conducted at The Aerospace Corporation was to develop and define methods for integrating the statistical theory of brittle strength with conventional finite element stress analysis, and to carry out a limited laboratory test program to illustrate the methods. The second part, separately funded at Aerojet Electronic Systems Division, was to create the finite element postprocessing program for integrating the statistical strength analysis with the structural analysis. The second part was monitored by Capt. Jeff McCann of USAF/SMC, as Special Study No.11, which authorized Aerojet to support Aerospace on this work requested by NASA. This second part is documented in Appendix A. The activity at Aerojet was guided by the Aerospace methods developed in the first part of this work. This joint work of Aerospace and Aerojet stemmed from prior related work for the Defense Support Program (DSP) Program Office, to qualify the DSP sensor main mirror and corrector lens for flight as part of a shuttle payload. These large brittle components of the DSP sensor are provided by Aerojet. This document defines rational methods for addressing the structural integrity and safety of large, brittle, payload components, which have low and variable tensile strength and can suddenly break or shatter. The methods are applicable to the evaluation and validation of such components, which, because of size and configuration restrictions, cannot be validated by direct proof test.

  4. 20th Aerospace Mechanisms Symposium. Revised

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The proceedings of the 20th Aerospace Mechanisms Symposium, hosted by the NASA Lewis Research Center, Cleveland, Ohio, on May 7-9, 1986, is documented herein. During the 3 days, 23 technical papers were presented by experts from the United States and Western Europe. A panel discussion by an International group of experts on future directions In mechanisms was also presented; this discussion, however, is not documented herein. The technical topics addressed included deployable structures, electromagnetic devices, tribology, thermal/mechanical/hydraulic actuators, latching devices, positioning mechanisms, robotic manipulators, and computerized mechanisms synthesis.

  5. Challenges in aerospace medicine education.

    PubMed

    Grenon, S Marlene; Saary, Joan

    2011-11-01

    Aerospace medicine training and research represents a dream for many and a challenge for most. In Canada, although some opportunities exist for the pursuit of education and research in the aerospace medicine field, they are limited despite the importance of this field for enabling safe human space exploration. In this commentary, we aim to identify some of the challenges facing individuals wishing to get involved in the field as well as the causal factors for these challenges. We also explore strategies to mitigate against these. PMID:22097645

  6. Second Aerospace Environmental Technology Conference

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F. (Editor); Clark-Ingram, M. (Editor)

    1997-01-01

    The mandated elimination of CFC'S, Halons, TCA, and other ozone depleting chemicals and specific hazardous materials has required changes and new developments in aerospace materials and processes. The aerospace industry has been involved for several years in providing product substitutions, redesigning entire production processes, and developing new materials that minimize or eliminate damage to the environment. These activities emphasize replacement cleaning solvents and their application, verification, compliant coatings including corrosion protection system and removal techniques, chemical propulsion effects on the environment, and the initiation of modifications to relevant processing and manufacturing specifications and standards.

  7. Second Aerospace Environmental Technology Conference

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F.; Clark-Ingram, M.; Hessler, S. L.

    1997-01-01

    The mandated elimination of CFC's, Halons, TCA, and other ozone depleting chemicals and specific hazardous materials has required changes and new developments in aerospace materials and processes. The aerospace industry has been involved for several years in providing product substitutions, redesigning entire production processes, and developing new materials that minimize or eliminate damage to the environment. These activities emphasize replacement cleaning solvents and their application verifications, compliant coatings including corrosion protection systems, and removal techniques, chemical propulsion effects on the environment, and the initiation of modifications to relevant processing and manufacturing specifications and standards.

  8. Reliability-based design optimization of multiphysics, aerospace systems

    NASA Astrophysics Data System (ADS)

    Allen, Matthew R.

    Aerospace systems are inherently plagued by uncertainties in their design, fabrication, and operation. Safety factors and expensive testing at the prototype level traditionally account for these uncertainties. Reliability-based design optimization (RBDO) can drastically decrease life-cycle development costs by accounting for the stochastic nature of the system response in the design process. The reduction in cost is amplified for conceptually new designs, for which no accepted safety factors currently exist. Aerospace systems often operate in environments dominated by multiphysics phenomena, such as the fluid-structure interaction of aeroelastic wings or the electrostatic-mechanical interaction of sensors and actuators. The analysis of such phenomena is generally complex and computationally expensive, and therefore is usually simplified or approximated in the design process. However, this leads to significant epistemic uncertainties in modeling, which may dominate the uncertainties for which the reliability analysis was intended. Therefore, the goal of this thesis is to present a RBDO framework that utilizes high-fidelity simulation techniques to minimize the modeling error for multiphysics phenomena. A key component of the framework is an extended reduced order modeling (EROM) technique that can analyze various states in the design or uncertainty parameter space at a reduced computational cost, while retaining characteristics of high-fidelity methods. The computational framework is verified and applied to the RBDO of aeroelastic systems and electrostatically driven sensors and actuators, utilizing steady-state analysis and design criteria. The framework is also applied to the design of electrostatic devices with transient criteria, which requires the use of the EROM technique to overcome the computational burden of multiple transient analyses.

  9. Aerospace Education for the Melting Pot.

    ERIC Educational Resources Information Center

    Joels, Kerry M.

    1979-01-01

    Aerospace education is eminently suited to provide a framework for multicultural education. Effective programs accommodating minorities' frames of reference to the rapidly developing disciplines of aerospace studies have been developed. (RE)

  10. Aerospace Education and the Elementary Teacher

    ERIC Educational Resources Information Center

    Jones, Robert M.

    1978-01-01

    This articles attempts to stimulate otherwise reluctant school teachers to involve aerospace education in their content repertoire. Suggestions are made to aid the teacher in getting started with aerospace education. (MDR)

  11. Accommodation of Nontraditional Aerospace Degree Aspirants

    ERIC Educational Resources Information Center

    Schukert, Michael A.

    1977-01-01

    Presents results of a national survey of institutions offering college level aerospace studies. Primary survey concern is the availability of nontraditional aerospace education programs; however, information pertaining to institution characteristics, program characteristics, and staffing are also included. (SL)

  12. Making Lightweight Structures By Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Goela, Jitendra S.; Pickering, Michael A.; Taylor, Raymond L.

    1990-01-01

    Technique developed for fabrication of stiff, strong, lightweight structures of silicon carbide or other materials by any of several deposition processes. Structures made by method can have complicated shapes. Ability to manufacture complex shape from pure deposited SiC useful and leads to new products in several fields. These lightweight structures used as backup structures for optical components, as structural components in automotive, aerospace, and outer space applications, and as lightweight parts of furniture for outer space.

  13. Measurement of wavefront structure from large aperture optical components by phase shifting interferometry

    SciTech Connect

    Wolfe, C.R.; Lawson, J.K.; Kellam, M.; Maney, R.T.; Demiris, A.

    1995-05-12

    This paper discusses the results of high spatial resolution measurement of the transmitted or reflected wavefront of optical components using phase shifting interferometry with a wavelength of 6328 {angstrom}. The optical components studied range in size from approximately 50 mm {times} 100 mm to 400 mm {times} 750 mm. Wavefront data, in the form of 3-D phase maps, have been obtained for three regimes of scale length: ``micro roughness``, ``mid-spatial scale``, and ``optical figure/curvature.`` Repetitive wavefront structure has been observed with scale lengths from 10 mm to 100 mm. The amplitude of this structure is typically {lambda}/100 to {lambda}/20. Previously unobserved structure has been detected in optical materials and on the surfaces of components. We are using this data to assist in optimizing laser system design, to qualify optical components and fabrication processes under study in our component development program.

  14. Probabilistic Structural Analysis Methods (PSAM) for Select Space Propulsion System Components

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Probabilistic Structural Analysis Methods (PSAM) are described for the probabilistic structural analysis of engine components for current and future space propulsion systems. Components for these systems are subjected to stochastic thermomechanical launch loads. Uncertainties or randomness also occurs in material properties, structural geometry, and boundary conditions. Material property stochasticity, such as in modulus of elasticity or yield strength, exists in every structure and is a consequence of variations in material composition and manufacturing processes. Procedures are outlined for computing the probabilistic structural response or reliability of the structural components. The response variables include static or dynamic deflections, strains, and stresses at one or several locations, natural frequencies, fatigue or creep life, etc. Sample cases illustrates how the PSAM methods and codes simulate input uncertainties and compute probabilistic response or reliability using a finite element model with probabilistic methods.

  15. Aerospace Training. Washington's Community and Technical Colleges

    ERIC Educational Resources Information Center

    Washington State Board for Community and Technical Colleges, 2014

    2014-01-01

    Aerospace is an economic powerhouse that generates jobs and fuels our economy. Washington's community and technical colleges produce the world-class employees needed to keep it that way. With about 1,250 aerospace-related firms employing more than 94,000 workers, Washington has the largest concentration of aerospace expertise in the nation. To…

  16. Analytical prediction of aerospace vehicle vibration environments

    NASA Technical Reports Server (NTRS)

    Wilby, J. F.; Piersol, A. G.

    1981-01-01

    Considerable attention has been given recently to the formulation and validation of analytical models for the prediction of aerospace vehicle vibration response to acoustic and fluctuating pressures. This paper summarizes the development of such analytical models for two applications, (1) structural vibrations of the Space Shuttle orbiter vehicle due to broadband rocket noise and aerodynamic boundary layer turbulence, and (2) structural vibrations of general aviation aircraft due to discrete frequency propeller and reciprocating engine exhaust noise. In both cases, the spatial exterior excitations are convected pressure fields which are described on the basis of measured cross spectra (coherence and phase) information. Structural modal data are obtained from analytical predictions, and structural responses to appropriate excitation fields are calculated. The results are compared with test data, and the strengths and weaknesses of the analytical models are assessed.

  17. Analytical prediction of aerospace vehicle vibration environments

    NASA Astrophysics Data System (ADS)

    Wilby, J. F.; Piersol, A. G.

    1981-09-01

    Considerable attention has been given recently to the formulation and validation of analytical models for the prediction of aerospace vehicle vibration response to acoustic and fluctuating pressures. This paper summarizes the development of such analytical models for two applications, (1) structural vibrations of the Space Shuttle orbiter vehicle due to broadband rocket noise and aerodynamic boundary layer turbulence, and (2) structural vibrations of general aviation aircraft due to discrete frequency propeller and reciprocating engine exhaust noise. In both cases, the spatial exterior excitations are convected pressure fields which are described on the basis of measured cross spectra (coherence and phase) information. Structural modal data are obtained from analytical predictions, and structural responses to appropriate excitation fields are calculated. The results are compared with test data, and the strengths and weaknesses of the analytical models are assessed.

  18. Extended Aging Theories for Predictions of Safe Operational Life of Critical Airborne Structural Components

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Chen, Tony

    2006-01-01

    The previously developed Ko closed-form aging theory has been reformulated into a more compact mathematical form for easier application. A new equivalent loading theory and empirical loading theories have also been developed and incorporated into the revised Ko aging theory for the prediction of a safe operational life of airborne failure-critical structural components. The new set of aging and loading theories were applied to predict the safe number of flights for the B-52B aircraft to carry a launch vehicle, the structural life of critical components consumed by load excursion to proof load value, and the ground-sitting life of B-52B pylon failure-critical structural components. A special life prediction method was developed for the preflight predictions of operational life of failure-critical structural components of the B-52H pylon system, for which no flight data are available.

  19. AGE-RELATED DEGRADATION OF NUCLEAR POWER PLANT STRUCTURES AND COMPONENTS.

    SciTech Connect

    BRAVERMAN,J.

    1999-03-29

    This paper summarizes and highlights the results of the initial phase of a research project on the assessment of aged and degraded structures and components important to the safe operation of nuclear power plants (NPPs). A review of age-related degradation of structures and passive components at NPPs was performed. Instances of age-related degradation have been collected and reviewed. Data were collected from plant generated documents such as Licensing Event Reports, NRC generic communications, NUREGs and industry reports. Applicable cases of degradation occurrences were reviewed and then entered into a computerized database. The results obtained from the review of degradation occurrences are summarized and discussed. Various trending analyses were performed to identify which structures and components are most affected, whether degradation occurrences are worsening, and what are the most common aging mechanisms. The paper also discusses potential aging issues and degradation-susceptible structures and passive components which would have the greatest impact on plant risk.

  20. Age-Related Degradation of Nuclear Power Plant Structures and Components

    SciTech Connect

    Braverman, J.; Chang, T.-Y.; Chokshi, N.; Hofmayer, C.; Morante, R.; Shteyngart, S.

    1999-03-29

    This paper summarizes and highlights the results of the initial phase of a research project on the assessment of aged and degraded structures and components important to the safe operation of nuclear power plants (NPPs). A review of age-related degradation of structures and passive components at NPPs was performed. Instances of age-related degradation have been collected and reviewed. Data were collected from plant generated documents such as Licensing Event Reports, NRC generic communications, NUREGs and industry reports. Applicable cases of degradation occurrences were reviewed and then entered into a computerized database. The results obtained from the review of degradation occurrences are summarized and discussed. Various trending analyses were performed to identify which structures and components are most affected, whether degradation occurrences are worsening, and what was the most common aging mechanisms. The paper also discusses potential aging issues and degradation-susceptible structures and passive components which would have the greatest impact on plant risk.

  1. Job Prospects for Aerospace Engineers.

    ERIC Educational Resources Information Center

    Basta, Nicholas

    1987-01-01

    Discusses the recent trends in job opportunities for aerospace engineers. Mentions some of the political, technological, and economic factors affecting the overall employment picture. Includes a description of the job prospects created by the general upswing of the large commercial aircraft market. (TW)

  2. Careers in the Aerospace Industry.

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC. Office of General Aviation.

    The document briefly presents career information in the field of aerospace industry. Employment exists in three areas: (1) professional and technical occupations in research and development (engineers, scientists, and technicians); (2) administrative, clerical, and related occupations (engineers, scientists, technicians, clerks, secretaries,…

  3. Technology utilization. [aerospace technology transfer

    NASA Technical Reports Server (NTRS)

    Kubokawa, C. C.

    1978-01-01

    NASA developed technologies were used to tackle problems associated with safety, transportation, industry, manufacturing, construction and state and local governments. Aerospace programs were responsible for more innovations for the benefit of mankind than those brought about by either major wars, or peacetime programs. Briefly outlined are some innovations for manned space flight, satellite surveillance applications, and pollution monitoring techniques.

  4. Graphical simulation for aerospace manufacturing

    NASA Technical Reports Server (NTRS)

    Babai, Majid; Bien, Christopher

    1994-01-01

    Simulation software has become a key technological enabler for integrating flexible manufacturing systems and streamlining the overall aerospace manufacturing process. In particular, robot simulation and offline programming software is being credited for reducing down time and labor cost, while boosting quality and significantly increasing productivity.

  5. Ball Aerospace Actuator Cryogenic Testing

    NASA Technical Reports Server (NTRS)

    Kingsbury, Lana; Lightsey, Paul; Quigley, Phil; Rutkowski, Joel; Russell, J. Kevin (Technical Monitor)

    2002-01-01

    The ambient testing characterizing step size and repeatability for the Ball Aerospace Cryogenic Nano-Positioner actuators for the AMSD (Advanced Mirror System Demonstrator) program has been completed and are presented. Current cryogenic testing is underway. Earlier cryogenic test results for a pre-cursor engineering model are presented.

  6. Aerospace for the Very Young.

    ERIC Educational Resources Information Center

    2003

    This packet includes games and activities concerning aerospace education for the very young. It is designed to develop and strengthen basic concepts and skills in a non-threatening atmosphere of fun. Activities include: (1) "The Sun, Our Nearest Star"; (2) "Twinkle, Twinkle, Little Star, How I Wonder Where You Are"; (3) "Shadows"; (4) "The Earth…

  7. Aerospace/Aviation Science Occupations.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Occupational Education.

    The guide was developed to provide secondary students the opportunity to study aviation and aerospace education from the conceptual and career approach coupled with general education specifically related to science. Unit plans were prepared to motivate, develop skills, and offer counseling to the students of aviation science and occupational…

  8. 33rd Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Boesiger, Edward A. (Compiler); Litty, Edward C. (Compiler); Sevilla, Donald R. (Compiler)

    1999-01-01

    The proceedings of the 33rd Aerospace Mechanisms Symposium are reported. JPL hosted the conference, which was held at the Pasadena Conference and Exhibition Center, Pasadena, California, on May 19-21, 1999. Lockheed Martin Missiles and Space cosponsored the symposium. Technology areas covered include bearings and tribology; pointing, solar array and deployment mechanisms; orbiter/space station; and other mechanisms for spacecraft.

  9. 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.

  10. Shape memory polymers and their composites in aerospace applications: a review

    NASA Astrophysics Data System (ADS)

    Liu, Yanju; Du, Haiyang; Liu, Liwu; Leng, Jinsong

    2014-02-01

    As a new class of smart materials, shape memory polymers and their composites (SMPs and SMPCs) can respond to specific external stimulus and remember the original shape. There are many types of stimulus methods to actuate the deformation of SMPs and SMPCs, of which the thermal- and electro-responsive components and structures are common. In this review, the general mechanism of SMPs and SMPCs are first introduced, the stimulus methods are then discussed to demonstrate the shape recovery effect, and finally, the applications of SMPs and SMPCs that are reinforced with fiber materials in aerospace are reviewed. SMPC hinges and booms are discussed in the part on components; the booms can be divided again into foldable SMPC truss booms, coilable SMPC truss booms and storable tubular extendible member (STEM) booms. In terms of SMPC structures, the solar array and deployable panel, reflector antenna and morphing wing are introduced in detail. Considering the factors of weight, recovery force and shock effect, SMPCs are expected to have great potential applications in aerospace.

  11. A Rayleigh-Ritz approach to the synthesis of large structures with rotating flexible components

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Hale, A. L.

    1976-01-01

    The equations of motion for large structures with rotating flexible components are derived by regarding the structure as an assemblage of substructures. Based on a stationarity principle for rotating structures, it is shown that each continuous or discrete substructure can be simulated by a suitable set of admissible functions or admissible vectors. This substructure synthesis approach provides a rational basis for truncating the number of degrees of freedom both of each substructure and of the assembled structure.

  12. Computational simulation of probabilistic lifetime strength for aerospace materials subjected to high temperature, mechanical fatigue, creep, and thermal fatigue

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Bast, Callie C.; Trimble, Greg A.

    1992-01-01

    The results of a fourth year effort of a research program conducted for NASA-LeRC by The University of Texas at San Antonio (UTSA) are presented. The research included on-going development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primitive variables. These primitive variables may include high temperature, fatigue, or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation was randomized and is included in the computer program, PROMISC. Also included in the research is the development of methodology to calibrate the above-described constitutive equation using actual experimental materials data together with regression analysis of that data, thereby predicting values for the empirical material constants for each effect or primitive variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from industry and the open literature for materials typically for applications in aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology.

  13. Computational simulation of probabilistic lifetime strength for aerospace materials subjected to high temperature, mechanical fatigue, creep and thermal fatigue

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Bast, Callie C.; Trimble, Greg A.

    1992-01-01

    This report presents the results of a fourth year effort of a research program, conducted for NASA-LeRC by the University of Texas at San Antonio (UTSA). The research included on-going development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subject to a number of effects or primitive variables. These primitive variables may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above-described constitutive equation using actual experimental materials data together with regression analysis of that data, thereby predicting values for the empirical material constants for each effect or primitive variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from industry and the open literature for materials typically for applications in aerospace propulsion system components. Material data for Inconel 718 has been analyzed using the developed methodology.

  14. Aerospace engineering curriculum for the 21st century

    NASA Technical Reports Server (NTRS)

    Simitses, George J.

    1995-01-01

    The second year of the study was devoted to completing the information-gathering phase of this redesign effort, using the conclusions from that activity to prepare the initial structure for the new curriculum, publicizing activities to a wider engineering forum, and preparing the department faculty (Aerospace Engineering and Engineering Mechanics at University of Cincinnati) for the roles they will play in the curriculum redesign and implementation. These activities are summarized briefly in this progress report. Attached is a paper resulting from the data acquisition of this effort, 'Educating Aerospace Engineers for the Twenty-First Century: Results of a Survey.'

  15. Lightning Protection Guidelines for Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Goodloe, C. C.

    1999-01-01

    This technical memorandum provides lightning protection engineering guidelines and technical procedures used by the George C. Marshall Space Flight Center (MSFC) Electromagnetics and Aerospace Environments Branch for aerospace vehicles. The overviews illustrate the technical support available to project managers, chief engineers, and design engineers to ensure that aerospace vehicles managed by MSFC are adequately protected from direct and indirect effects of lightning. Generic descriptions of the lightning environment and vehicle protection technical processes are presented. More specific aerospace vehicle requirements for lightning protection design, performance, and interface characteristics are available upon request to the MSFC Electromagnetics and Aerospace Environments Branch, mail code EL23.

  16. Sonic fatigue of launch vehicle components

    SciTech Connect

    Wentz, K.R.; Camden, M.P.

    1997-01-01

    Wright Laboratory has long been a leader in the technologies required for aerospace structures. One of these driving technology areas is that of the dynamic environments of acoustics and vibration to which structures are exposed and required to survive. This paper presents an overview of sonic fatigue of launch vehicle components. An experimental program to develop sonic fatigue design criteria for a proposed thermal protection system is reviewed. Wright Laboratory{close_quote}s experimental facilities utilized to subject structures to simulated launch vehicle environments which are necessary to generate the experimental data required to provide sonic fatigue design criteria are described. {copyright} {ital 1997 American Institute of Physics.}

  17. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The results of the Panel's activities are presented in a set of findings and recommendations. Highlighted here are both improvements in NASA's safety and reliability activities and specific areas where additional gains might be realized. One area of particular concern involves the curtailment or elimination of Space Shuttle safety and reliability enhancements. Several findings and recommendations address this area of concern, reflecting the opinion that safety and reliability enhancements are essential to the continued successful operation of the Space Shuttle. It is recommended that a comprehensive and continuing program of safety and reliability improvements in all areas of Space Shuttle hardware/software be considered an inherent component of ongoing Space Shuttle operations.

  18. High Performance Fortran for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Mehrotra, Piyush; Zima, Hans; Bushnell, Dennis M. (Technical Monitor)

    2000-01-01

    This paper focuses on the use of High Performance Fortran (HPF) for important classes of algorithms employed in aerospace applications. HPF is a set of Fortran extensions designed to provide users with a high-level interface for programming data parallel scientific applications, while delegating to the compiler/runtime system the task of generating explicitly parallel message-passing programs. We begin by providing a short overview of the HPF language. This is followed by a detailed discussion of the efficient use of HPF for applications involving multiple structured grids such as multiblock and adaptive mesh refinement (AMR) codes as well as unstructured grid codes. We focus on the data structures and computational structures used in these codes and on the high-level strategies that can be expressed in HPF to optimally exploit the parallelism in these algorithms.

  19. 76 FR 69292 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    .... ML100920158), for which a notice of availability was published in the Federal Register on June 22, 2010 (75 FR... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY... Staff Guidance (LR-ISG), LR- ISG-2011-01, ``Aging Management of Stainless Steel Structures...

  20. On bi-Hamiltonian structure of two-component Novikov equation

    NASA Astrophysics Data System (ADS)

    Li, Nianhua; Liu, Q. P.

    2013-01-01

    In this Letter, we present a bi-Hamiltonian structure for the two-component Novikov equation. We also show that proper reduction of this bi-Hamiltonian structure leads to the Hamiltonian operators found by Hone and Wang for the Novikov equation.

  1. Aerospace safety advisory panel

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Data acquired on the actual flight experience with the various subsystems are assessed. These subsystems include: flight control and performance, structural integrity, orbiter landing gear, lithium batteries, EVA and prebreathing, and main engines. Improvements for routine operations are recommended. Policy issues for operations and flight safety for aircraft operations are discussed.

  2. Vlasov Simulation of Electrostatic Solitary Structures in Multi-Component Plasmas

    NASA Technical Reports Server (NTRS)

    Umeda, Takayuki; Ashour-Abdalla, Maha; Pickett, Jolene S.; Goldstein, Melvyn L.

    2012-01-01

    Electrostatic solitary structures have been observed in the Earth's magnetosheath by the Cluster spacecraft. Recent theoretical work has suggested that these solitary structures are modeled by electron acoustic solitary waves existing in a four-component plasma system consisting of core electrons, two counter-streaming electron beams, and one species of background ions. In this paper, the excitation of electron acoustic waves and the formation of solitary structures are studied by means of a one-dimensional electrostatic Vlasov simulation. The present result first shows that either electron acoustic solitary waves with negative potential or electron phase-space holes with positive potential are excited in four-component plasma systems. However, these electrostatic solitary structures have longer duration times and higher wave amplitudes than the solitary structures observed in the magnetosheath. The result indicates that a high-speed and small free energy source may be needed as a fifth component. An additional simulation of a five-component plasma consisting of a stable four-component plasma and a weak electron beam shows the generation of small and fast electron phase-space holes by the bump-on-tail instability. The physical properties of the small and fast electron phase-space holes are very similar to those obtained by the previous theoretical analysis. The amplitude and duration time of solitary structures in the simulation are also in agreement with the Cluster observation.

  3. Structures for attaching or sealing a space between components having different coefficients or rates of thermal expansion

    DOEpatents

    Corman, Gregory Scot; Dean, Anthony John; Tognarelli, Leonardo; Pecchioli, Mario

    2005-06-28

    A structure for attaching together or sealing a space between a first component and a second component that have different rates or amounts of dimensional change upon being exposed to temperatures other than ambient temperature. The structure comprises a first attachment structure associated with the first component that slidably engages a second attachment structure associated with the second component, thereby allowing for an independent floating movement of the second component relative to the first component. The structure can comprise split rings, laminar rings, or multiple split rings.

  4. Third Aerospace Environmental Technology Conference

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F. (Editor); Cross, D. R. (Editor); Caruso, S. V. (Editor); Clark-Ingram, M. (Editor)

    1999-01-01

    The elimination of CFC's, Halons, TCA, other ozone depleting chemicals, and specific hazardous materials is well underway. The phaseout of these chemicals has mandated changes and new developments in aerospace materials and processes. We are beyond discovery and initiation of these new developments and are now in the implementation phase. This conference provided a forum for materials and processes engineers, scientists, and managers to describe, review, and critically assess the evolving replacement and clean propulsion technologies from the standpoint of their significance, application, impact on aerospace systems, and utilization by the research and development community. The use of these new technologies, their selection and qualification, their implementation, and the needs and plans for further developments are presented.

  5. Pathways and Challenges to Innovation in Aerospace

    NASA Technical Reports Server (NTRS)

    Terrile, Richard J.

    2010-01-01

    This paper explores impediments to innovation in aerospace and suggests how successful pathways from other industries can be adopted to facilitate greater innovation. Because of its nature, space exploration would seem to be a ripe field of technical innovation. However, engineering can also be a frustratingly conservative endeavor when the realities of cost and risk are included. Impediments like the "find the fault" engineering culture, the treatment of technical risk as almost always evaluated in terms of negative impact, the difficult to account for expansive Moore's Law growth when making predictions, and the stove-piped structural organization of most large aerospace companies and federally funded research laboratories tend to inhibit cross-cutting technical innovation. One successful example of a multi-use cross cutting application that can scale with Moore's Law is the Evolutionary Computational Methods (ECM) technique developed at the Jet Propulsion Lab for automated spectral retrieval. Future innovations like computational engineering and automated design optimization can potentially redefine space exploration, but will require learning lessons from successful innovators.

  6. Advanced electromagnetic methods for aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Choi, Jachoon; El-Sharawy, El-Budawy; Hashemi-Yeganeh, Shahrokh; Birtcher, Craig R.

    1990-01-01

    High- and low-frequency methods to analyze various radiation elements located on aerospace vehicles with combinations of conducting, nonconducting, and energy absorbing surfaces and interfaces. The focus was on developing fundamental concepts, techniques, and algorithms which would remove some of the present limitations in predicting radiation characteristics of antennas on complex aerospace vehicles. In order to accomplish this, the following subjects were examined: (1) the development of techniques for rigorous analysis of surface discontinuities of metallic and nonmetallic surfaces using the equivalent surface impedance concept and Green's function; (2) the effects of anisotropic material on antenna radiation patterns through the use of an equivalent surface impedance concept which is incorporated into the existing numerical electromagnetics computer codes; and (3) the fundamental concepts of precipitation static (P-Static), such as formulations and analytical models. A computer code was used to model the P-Static process on a simple structure. Measurement techniques were also developed to characterized the electrical properties at microwave frequencies. Samples of typical materials used in airframes were tested and the results are included.

  7. [Aerospace radiobiology: 35 years (1960-1995)].

    PubMed

    Ushakov, I B; Davydov, B I

    1996-01-01

    The paper gives a brief history of the birth and development of aerospace radiobiology at the Institute of Aviation and Space Medicine. It covers from the first radiobiological investigations in space to the insurance of radiation safety for helicopter air crews who took part in cleaning-up operations of consequences of the Chernobyl accident. The workers of the Radiobiological Laboratory have performed some research theoretical and practical tasks in the interests of aviation and space, civil and military medicine: the impact of gravitation and radiation on genetic structures has been studied, a radiation safety system for vehicles of different use has been developed, new principles in the standardization of EMF for radiofrequency and microwave bands have been proposed, the new radioprotective agent indralin (B, B-190) has been discovered, which is accepted for supply and used in rotary wing aircraft pilots during liquidation works at the Chernobyl atomic power station. New experimental data on the combined effects of radiation and non-radiation flight factors have been obtained. Basically new data on the mechanism of action of ionizing and non-ionizing radiation on the brain have been also gained, a system for assessing the health and rehabilitation of pilots that cleaned-up the Chernobyl accident has been developed. Professor Pavel Petrovich Saksonov, RF Honoured Scientist, has the honour to create a school of aerospace radiobiology. PMID:8963185

  8. Chemical Microsensor Development for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Xu, Jennifer C.; Hunter, Gary W.; Lukco, Dorothy; Chen, Liangyu; Biaggi-Labiosa, Azlin M.

    2013-01-01

    Numerous aerospace applications, including low-false-alarm fire detection, environmental monitoring, fuel leak detection, and engine emission monitoring, would benefit greatly from robust and low weight, cost, and power consumption chemical microsensors. NASA Glenn Research Center has been working to develop a variety of chemical microsensors with these attributes to address the aforementioned applications. Chemical microsensors using different material platforms and sensing mechanisms have been produced. Approaches using electrochemical cells, resistors, and Schottky diode platforms, combined with nano-based materials, high temperature solid electrolytes, and room temperature polymer electrolytes have been realized to enable different types of microsensors. By understanding the application needs and chemical gas species to be detected, sensing materials and unique microfabrication processes were selected and applied. The chemical microsensors were designed utilizing simple structures and the least number of microfabrication processes possible, while maintaining high yield and low cost. In this presentation, an overview of carbon dioxide (CO2), oxygen (O2), and hydrogen/hydrocarbons (H2/CxHy) microsensors and their fabrication, testing results, and applications will be described. Particular challenges associated with improving the H2/CxHy microsensor contact wire-bonding pad will be discussed. These microsensors represent our research approach and serve as major tools as we expand our sensor development toolbox. Our ultimate goal is to develop robust chemical microsensor systems for aerospace and commercial applications.

  9. 30th Aerospace Mechanisms Symposium

    NASA Technical Reports Server (NTRS)

    Bradley, Obie H., Jr. (Compiler); Rogers, John F. (Compiler)

    1996-01-01

    The proceedings of the 30th Aerospace Mechanisms Symposium are reported. NASA Langley Research Center hosted the proceedings held at the Radisson Hotel in Hampton, Virginia on May 15-17, 1996, and Lockheed Martin Missiles and Space Company, Inc. co-sponsored the symposium. Technological areas covered include bearings and tribology; pointing, solar array, and deployment mechanisms; orbiter/space station; and other mechanisms for spacecraft.

  10. KIBO Industry, innovates in aerospace

    NASA Astrophysics Data System (ADS)

    Katayama, Naomi; Paillard, Jean-Philippe

    2016-07-01

    The conquest of space is a true inspiration. Imagine a long-duration mission to a distant destination. What shall we take to produce our food? A cow, fish, chicken, or just eggs. In the current state of the animal production technologies are complicated and expensive to implement, except perhaps one: the breeding of edible insects. Based on industry KIBO is postulated in partnership with Space Agriculture Task Force and the university's department of Nutrition Nagoya most innovative research program is created in modern nutrition. This program is called Pegasus. Pegasus research program aims to develop food productions and modules applicable to the aerospace conquest. Kibo entomocole industry is the first production company in Europe to human food, it aims to become the world leader by 2020. Kibo industry is particularly specialized in producing entomosource (products with insects). The first phase of the program is to achieve an outcome cereal bar edible insect to aerospace. So we will present the issues and objectives of the project, for aerospace and us. Jean-Philippe Paillard is the KIBO industry CEO and Vice President of the FFPIDI insects farms federation. He is also the co computer alone authorization dossier on the market in Europe and therefore the privileged interlocutor of the General Directorate for Health and Customer Review on this topic. He intervened at the last conference on the insect organized by FAO in Wageningen and in the universities of Angers, Nantes, Lille.

  11. KIBO Industry, innovates in aerospace

    NASA Astrophysics Data System (ADS)

    Paillard, Jean-Philippe

    2016-07-01

    The conquest of space is a true inspiration. Imagine a long-duration mission to a distant destination. What shall we take to produce our food? A cow, fish, chicken, or just eggs. In the current state of the animal production technologies are complicated and expensive to implement, except perhaps one: the breeding of edible insects. Based on this postulate KIBO in partnership with Space Agriculture Task Force and the university's department of Nutrition Nagoya most innovative research program is created in modern nutrition. This program is called Pegasus. Pegasus research program aims to develop food productions and modules applicable to the aerospace conquest. Kibo industry is the first entomocole production company creat in Europe to human food; it aims to become the world leader by 2020. Kibo industry is particularly specialized in producing entomosource (products with insects). The first phase of the program is to achieve an outcome cereal bar edible insect to aerospace. So we will present the issues and objectives of the project, for aerospace and us. Jean-Philippe Paillard is the KIBO industry CEO and Vice President of the FFPIDI insects farms federation. He is also the co computer alone authorization dossier on the market in Europe and therefore the privileged interlocutor of the General Directorate for Health and Customer Review on this topic. He intervened at the last conference on the insect organized by FAO in Wageningen and various universities in France.

  12. Ball Aerospace Hybrid Space Cryocoolers

    NASA Astrophysics Data System (ADS)

    Gully, W.; Glaister, D. S.; Hendershott, P.; Kotsubo, V.; Lock, J. S.; Marquardt, E.

    2008-03-01

    This paper describes the design, development, testing, and performance at Ball Aerospace of a long-life hybrid (combination of Stirling and Joule-Thomson [J-T] thermodynamic cycles) space cryocooler. Hybrid coolers are synergistic combinations of two thermodynamic cycles that combine advantages of each cycle to yield overall improved performance. Hybrid cooler performance advantages include: 1) load leveling of large heat loads; 2) remote cryogenic cooling with very low to negligible induced vibration and jitter; 3) very low redundant (off state) cooler penalties; 4) high power efficiency, especially at low temperatures; and 5) simplified system integration with capability to cross gimbals and no need for thermal straps or switches. Ball Aerospace is currently developing several different hybrid cooler systems. The 35 K hybrid cooler provides 2.0 W at 35 K and 8.5 W at 85 K with an emphasis on load leveling of high transient heat loads and remote, low vibration cooling. The 10 K hybrid cooler provides 200 mW at 10 K, 700 mW at 15 K, and 10.7 W at 85 K with an emphasis on power efficiency. In addition, Ball Aerospace built and tested a complete hybrid cooler that met the requirements of the JWST Mid-Infrared Instrument (MIRI) cooler including providing 80 mW at 6 K and 100 mW at 18 K for a total system (28 V) power of 310 W.

  13. Computational Control of Flexible Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Sharpe, Lonnie, Jr.; Shen, Ji Yao

    1994-01-01

    The main objective of this project is to establish a distributed parameter modeling technique for structural analysis, parameter estimation, vibration suppression and control synthesis of large flexible aerospace structures. This report concentrates on the research outputs produced in the last two years of the project. The main accomplishments can be summarized as follows. A new version of the PDEMOD Code had been completed. A theoretical investigation of the NASA MSFC two-dimensional ground-based manipulator facility by using distributed parameter modelling technique has been conducted. A new mathematical treatment for dynamic analysis and control of large flexible manipulator systems has been conceived, which may provide a embryonic form of a more sophisticated mathematical model for future modified versions of the PDEMOD Codes.

  14. Aerospace modal test optimization using VETO (virtual environment for test optimization)

    SciTech Connect

    Klenke, S.E.; Reese, G.M.; Schoof, L.A.; Shierling, C.L.

    1995-12-31

    We present a software environment integrating analysis and test based models to support optimal modal test design of aerospace components through a Virtual Environment for Test Optimization (VETO). A goal in developing this software tool is to provide test and analysis organizations with a capability of mathematically simulating the complete test environment within a computer. Derived models of test equipment, instrumentation and hardware can be combined within the VETO to provide the user with a unique analysis and visualization capability to evaluate new and existing test methods. The VETO assists analysis and test engineers in maximizing the value of each modal test. It is particularly advantageous for structural dynamics model reconciliation applications. The VETO enables an engineer to interact with a finite element model of an aerospace component to optimally place sensors and exciters and to investigate the selection of data acquisition parameters needed to conduct a complete modal survey. Additionally, the user can evaluate the use of different types of instrumentation such as filters, amplifiers and transducers for which models are available in the VETO. The dynamic response of most of the virtual instruments (including the device under test) are modeled in the state space domain. Design of modal excitation levels and appropriate test instrumentation are facilitated by the VETO`s ability to simulate such features as unmeasured external inputs, A/D quantization effects, and electronic noise.

  15. Design search and optimization in aerospace engineering.

    PubMed

    Keane, A J; Scanlan, J P

    2007-10-15

    In this paper, we take a design-led perspective on the use of computational tools in the aerospace sector. We briefly review the current state-of-the-art in design search and optimization (DSO) as applied to problems from aerospace engineering, focusing on those problems that make heavy use of computational fluid dynamics (CFD). This ranges over issues of representation, optimization problem formulation and computational modelling. We then follow this with a multi-objective, multi-disciplinary example of DSO applied to civil aircraft wing design, an area where this kind of approach is becoming essential for companies to maintain their competitive edge. Our example considers the structure and weight of a transonic civil transport wing, its aerodynamic performance at cruise speed and its manufacturing costs. The goals are low drag and cost while holding weight and structural performance at acceptable levels. The constraints and performance metrics are modelled by a linked series of analysis codes, the most expensive of which is a CFD analysis of the aerodynamics using an Euler code with coupled boundary layer model. Structural strength and weight are assessed using semi-empirical schemes based on typical airframe company practice. Costing is carried out using a newly developed generative approach based on a hierarchical decomposition of the key structural elements of a typical machined and bolted wing-box assembly. To carry out the DSO process in the face of multiple competing goals, a recently developed multi-objective probability of improvement formulation is invoked along with stochastic process response surface models (Krigs). This approach both mitigates the significant run times involved in CFD computation and also provides an elegant way of balancing competing goals while still allowing the deployment of the whole range of single objective optimizers commonly available to design teams. PMID:17519198

  16. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1984-01-01

    An assessment of NASA's safety performance for 1983 affirms that NASA Headquarters and Center management teams continue to hold the safety of manned flight to be their prime concern, and that essential effort and resources are allocated for maintaining safety in all of the development and operational programs. Those conclusions most worthy of NASA management concentration are given along with recommendations for action concerning; product quality and utility; space shuttle main engine; landing gear; logistics and management; orbiter structural loads, landing speed, and pitch control; the shuttle processing contractor; and the safety of flight operations. It appears that much needs to be done before the Space Transportation System can achieve the reliability necessary for safe, high rate, low cost operations.

  17. Implications of Pb-free microelectronics assembly in aerospace applications

    NASA Technical Reports Server (NTRS)

    Shapiro, A. A.; Bonner, J. K.; Ogunseitan, D.; Saphores, J. D.; Schoenung, J.

    2003-01-01

    The commercial microelectronics industry is rapidly moving to completely Pb-free assembly strategies within the next decade. This trend is being driven by existing and proposed legislation in Europe and in Japan. The microelectronics industry has become truly global, as indicated by major U .S. firms who already adopted Pb-free implementation programs. Among these forward-looking firms are AT&T, IBM, Motorola, HP and Intel to name a few.Following Moore's law, advances in microelectronics are happening very rapidly. In many cases, commercial industry is ahead of the aerospace sector in technology. Progress by commercial industry, along with cost, drives the use of Commercial Off-The-Shelf (COTS) parts for military and space applications. We can thus anticipate that the aerospace industry will, at some point, be forced to use Pb-free components and subsystems as part of their standard business practices. In this paper we attempt to provide a snapshot of the commercial industry trends and how they may impact electronics in the aerospace environment. In addition, we also look at different strategies for implementation. Finally we present data collected on a recent NASA project to focus on finding suitable alternatives to eutectic tin-lead solders and solder pastes. The world is moving toward implementation of environmentally friendly manufacturing techniques. The aerospace industry will be forced to deal with issues related with Pb free assembly, either by availability or legislation. This paper provides some insight into some of the tradeoffs that should be considered.

  18. A standardized Cernox™ cryogenic temperature sensor for aerospace applications

    NASA Astrophysics Data System (ADS)

    Courts, Samuel Scott

    2014-11-01

    The success of any aerospace mission depends upon the reliability of the discrete components comprising the instrument. To this end, many test standards have been developed to define test protocols and methods for the parts used in these missions. To date, no recognized MIL-type standard exists for cryogenic temperature sensors that are used from room temperature to 20 K or below. The aerospace applications utilizing these sensors require the procuring entity to develop a specification which the sensor manufacturer uses to screen and qualify a single build lot for flight use. The individual applications often require only a small number of sensors with the end result being a relatively high cost and long delivery time. Over the past two decades, Lake Shore Cryotronics, Inc. has worked with many aerospace companies to supply Cernox™ cryogenic temperature sensors for numerous missions. The experience gained from this work has led to the development of a manufacturing and test protocol resulting in 'off-the-shelf' cryogenic temperature sensors that should meet the requirements for many aerospace applications. Sensors will be available at the base part level with the ability to configure the delivered part with regard to lead wire material, package adapter, lead wire extensions, and calibration as appropriate or necessary for the application. This work presents details of this manufacturing, inspection, and test protocol as well as performance characteristics of Cernox™ temperature sensors when inspected and tested to this protocol.

  19. Component-Based Syntheses of Trioxacarcin A, DC-45-A1, and Structural Analogs

    PubMed Central

    Magauer, Thomas; Smaltz, Daniel J.; Myers, Andrew G.

    2014-01-01

    The trioxacarcins are polyoxygenated, structurally complex natural products that potently inhibit the growth of cultured human cancer cells. Here we describe syntheses of trioxacarcin A, DC-45-A1, and structural analogs by latestage, stereoselective glycosylation reactions of fully functionalized, differentially protected aglycon substrates. Key issues addressed in this work include the identification of an appropriate means to activate and protect each of the two 2-deoxysugar components, trioxacarcinose A and trioxacarcinose B, as well as a viable sequencing of the glycosidic couplings. The convergent, component-based sequence we present allows for rapid construction of structurally diverse, synthetic analogs that would be inaccessible by any other means, in amounts required to support biological evaluation. Analogs arising from modification of four of five modular components are assembled in 11 steps or fewer. The majority of these are found to be active in antiproliferative assays using cultured human cancer cells. PMID:24056347

  20. Component-based syntheses of trioxacarcin A, DC-45-A1 and structural analogues

    NASA Astrophysics Data System (ADS)

    Magauer, Thomas; Smaltz, Daniel J.; Myers, Andrew G.

    2013-10-01

    The trioxacarcins are polyoxygenated, structurally complex natural products that potently inhibit the growth of cultured human cancer cells. Here we describe syntheses of trioxacarcin A, DC-45-A1 and structural analogues by late-stage stereoselective glycosylation reactions of fully functionalized, differentially protected aglycon substrates. Key issues addressed in this work include the identification of an appropriate means to activate and protect each of the two 2-deoxysugar components, trioxacarcinose A and trioxacarcinose B, as well as a viable sequencing of the glycosidic couplings. The convergent, component-based sequence we present allows for rapid construction of structurally diverse, synthetic analogues that would be inaccessible by any other means, in amounts required to support biological evaluation. Analogues that arise from the modification of four of five modular components are assembled in 11 steps or fewer. The majority of these are found to be active in antiproliferative assays using cultured human cancer cells.