On the design and structural analysis of jet engine fan blade structures

NASA Astrophysics Data System (ADS)

Amoo, Leye M.

2013-07-01

Progress in the design and structural analysis of commercial jet engine fan blades is reviewed and presented. This article is motivated by the key role fan blades play in the performance of advanced gas turbine jet engines. The fundamentals of the associated physics are emphasized. Recent developments and advancements have led to an increase and improvement in fan blade structural durability, stability and reliability. This article is intended as a high level review of the fan blade environment and current state of structural design to aid further research in developing new and innovative fan blade technologies.

Protein Engineering Approaches in the Post-Genomic Era.

PubMed

Singh, Raushan K; Lee, Jung-Kul; Selvaraj, Chandrabose; Singh, Ranjitha; Li, Jinglin; Kim, Sang-Yong; Kalia, Vipin C

2018-01-01

Proteins are one of the most multifaceted macromolecules in living systems. Proteins have evolved to function under physiological conditions and, therefore, are not usually tolerant of harsh experimental and environmental conditions. The growing use of proteins in industrial processes as a greener alternative to chemical catalysts often demands constant innovation to improve their performance. Protein engineering aims to design new proteins or modify the sequence of a protein to create proteins with new or desirable functions. With the emergence of structural and functional genomics, protein engineering has been invigorated in the post-genomic era. The three-dimensional structures of proteins with known functions facilitate protein engineering approaches to design variants with desired properties. There are three major approaches of protein engineering research, namely, directed evolution, rational design, and de novo design. Rational design is an effective method of protein engineering when the threedimensional structure and mechanism of the protein is well known. In contrast, directed evolution does not require extensive information and a three-dimensional structure of the protein of interest. Instead, it involves random mutagenesis and selection to screen enzymes with desired properties. De novo design uses computational protein design algorithms to tailor synthetic proteins by using the three-dimensional structures of natural proteins and their folding rules. The present review highlights and summarizes recent protein engineering approaches, and their challenges and limitations in the post-genomic era. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Investigation of Exoskeletal Engine Propulsion System Concept

NASA Technical Reports Server (NTRS)

Roche, Joseph M.; Palac, Donald T.; Hunter, James E.; Myers, David E.; Snyder, Christopher A.; Kosareo, Daniel N.; McCurdy, David R.; Dougherty, Kevin T.

2005-01-01

An innovative approach to gas turbine design involves mounting compressor and turbine blades to an outer rotating shell. Designated the exoskeletal engine, compression (preferable to tension for high-temperature ceramic materials, generally) becomes the dominant blade force. Exoskeletal engine feasibility lies in the structural and mechanical design (as opposed to cycle or aerothermodynamic design), so this study focused on the development and assessment of a structural-mechanical exoskeletal concept using the Rolls-Royce AE3007 regional airliner all-axial turbofan as a baseline. The effort was further limited to the definition of an exoskeletal high-pressure spool concept, where the major structural and thermal challenges are represented. The mass of the high-pressure spool was calculated and compared with the mass of AE3007 engine components. It was found that the exoskeletal engine rotating components can be significantly lighter than the rotating components of a conventional engine. However, bearing technology development is required, since the mass of existing bearing systems would exceed rotating machinery mass savings. It is recommended that once bearing technology is sufficiently advanced, a "clean sheet" preliminary design of an exoskeletal system be accomplished to better quantify the potential for the exoskeletal concept to deliver benefits in mass, structural efficiency, and cycle design flexibility.

Thermal-structural design study of an airframe-integrated Scramjet

NASA Technical Reports Server (NTRS)

Killackey, J. J.; Katinsky, E. A.; Tepper, S.; Vuigner, A. A.

1978-01-01

Design concepts are developed and evaluated for a cooled structures assembly for the Scramjet engine, for engine subsystems mass, volume, and operating requirements, and for the aircraft/engine interface. A thermal protection system was defined that makes it possible to attain a life of 100 hours and 1000 cycles. The coolant equivalence ratio at the Mach 10 maximum thermal loading condition is 0.6, indicating a capacity for airframe cooling. The mechanical design is feasible for manufacture using conventional materials. For the cooled structures in a six-module engine, the mass per unit capture area is 12.4 KN/sq m. The total weight of a six-module engine assembly including the fuel system is 14.73 KN.

Materials and structural aspects of advanced gas-turbine helicopter engines

NASA Technical Reports Server (NTRS)

Freche, J. C.; Acurio, J.

1979-01-01

The key to improved helicopter gas turbine engine performance lies in the development of advanced materials and advanced structural and design concepts. The modification of the low temperature components of helicopter engines (such as the inlet particle separator), the introduction of composites for use in the engine front frame, the development of advanced materials with increased use-temperature capability for the engine hot section, can result in improved performance and/or decreased engine maintenance cost. A major emphasis in helicopter engine design is the ability to design to meet a required lifetime. This, in turn, requires that the interrelated aspects of higher operating temperatures and pressures, cooling concepts, and environmental protection schemes be integrated into component design. The major material advances, coatings, and design life-prediction techniques pertinent to helicopter engines are reviewed; the current state-of-the-art is identified; and when appropriate, progress, problems, and future directions are assessed.

Computer-Aided Structural Engineering (CASE) Project: State of the Art on Expert Systems Applications in Design, Construction and Maintenance of Structures

DTIC Science & Technology

1989-09-01

OGT, F1EPQRTJTL4, W" - 3^ n"r-- n *ON EXPERT SYSTEMS IN DESIGN, CONSTRUCTION AND’, IWAJNTENANCE-OF STRUCTURES Arockiasamy, Sunghoon Lee Clepartrhent...based expert system applications in the areas of structural design, design standards, and construction planning. This study will aid in the development...of a comprehensive expert system for tvical hydraulic structures. Funding for this report was provided by the US Army Engineer Waterways Experiment

Key issues in theoretical and functional pneumatic design

NASA Astrophysics Data System (ADS)

Xu, Z. G.; Yang, D. Y.; Liu, W. M.; Liu, T. T.

2017-10-01

This paper studies the energy release of the pneumatic engine in different thermodynamic processes, the isothermal process is the highest power output process, while adiabatic process is the lowest energy output process, and the energy release of the pneumatic engine is a multi-state thermodynamic process between them. Therefore heat exchanging should be increased between the pneumatic engine and the outer space, the gas expansion process in the cylinder should be as close as possible to the isothermal process. Heat exchange should be increased between the cylinder and the external spaces. Secondly, the fin structure is studied to increase the heat exchanging between the cylinder body and the outside space. The upper part has fin structures and the lower cylinder has no fin structure, this structure improved the working efficiency of pneumatic engine. Finally the cam and the hydraulic bottle of pneumatic engines are designed. Simulation and theoretical calculation are used to the analysis of the whole structure, which lay the foundation for the manufacturing and design of the pneumatic engines.

Protein engineering and the use of molecular modeling and simulation: the case of heterodimeric Fc engineering.

PubMed

Spreter Von Kreudenstein, Thomas; Lario, Paula I; Dixit, Surjit B

2014-01-01

Computational and structure guided methods can make significant contributions to the development of solutions for difficult protein engineering problems, including the optimization of next generation of engineered antibodies. In this paper, we describe a contemporary industrial antibody engineering program, based on hypothesis-driven in silico protein optimization method. The foundational concepts and methods of computational protein engineering are discussed, and an example of a computational modeling and structure-guided protein engineering workflow is provided for the design of best-in-class heterodimeric Fc with high purity and favorable biophysical properties. We present the engineering rationale as well as structural and functional characterization data on these engineered designs. Copyright © 2013 Elsevier Inc. All rights reserved.

Multidisciplinary Simulation of Graphite-Composite and Cermet Fuel Elements for NTP Point of Departure Designs

NASA Technical Reports Server (NTRS)

Stewart, Mark E.; Schnitzler, Bruce G.

2015-01-01

This paper compares the expected performance of two Nuclear Thermal Propulsion fuel types. High fidelity, fluid/thermal/structural + neutronic simulations help predict the performance of graphite-composite and cermet fuel types from point of departure engine designs from the Nuclear Thermal Propulsion project. Materials and nuclear reactivity issues are reviewed for each fuel type. Thermal/structural simulations predict thermal stresses in the fuel and thermal expansion mis-match stresses in the coatings. Fluid/thermal/structural/neutronic simulations provide predictions for full fuel elements. Although NTP engines will utilize many existing chemical engine components and technologies, nuclear fuel elements are a less developed engine component and introduce design uncertainty. Consequently, these fuel element simulations provide important insights into NTP engine performance.

Designing, engineering, and testing wood structures

NASA Technical Reports Server (NTRS)

Gorman, Thomas M.

1992-01-01

The objective of this paper is to introduce basic structural engineering concepts in a clear, simple manner while actively involving students. This project emphasizes the fact that a good design uses materials efficiently. The test structure in this experiment can easily be built and has various design options. Even when the structure is loaded to collapsing, only one or two pieces usually break, leaving the remaining pieces intact and reusable.

Structural and Machine Design Using Piezoceramic Materials: A Guide for Structural Design Engineers

NASA Technical Reports Server (NTRS)

Inman, Daniel J.; Cudney, Harley H.

2000-01-01

Using piezoceramic materials is one way the design engineer can create structures which have an ability to both sense and respond to their environment. Piezoceramic materials can be used to create structural sensors and structural actuators. Because piezoceramic materials have transduction as a material property, their sensing or actuation functions are a result of what happens to the material. This is different than discrete devices we might attach to the structure. For example, attaching an accelerometer to a structure will yield an electrical signal proportional to the acceleration at the attachment point on the structure. Using a electromagnetic shaker as an actuator will create an applied force at the attachment point. Active material elements in a structural design are not easily modeled as providing transduction at a point, but rather they change the physics of the structure in the areas where they are used. Hence, a designer must not think of adding discrete devices to a structure to obtain an effect, but rather must design a structural system which accounts for the physical principles of all the elements in the structure. The purpose of this manual is to provide practicing engineers the information necessary to incorporate piezoelectric materials in structural design and machine design. First, we will review the solid-state physics of piezoelectric materials. Then we will discuss the physical characteristics of the electrical-active material-structural system. We will present the elements of this system which must be considered as part of the design task for a structural engineer. We will cover simple modeling techniques and review the features and capabilities of commercial design tools that are available. We will then cover practical how-to elements of working with piezoceramic materials. We will review sources of piezoceramic materials and built-up devices, and their characteristics. Finally, we will provide two design examples using piezoceramic materials, first as discrete actuators for vibration isolation, and second as structurally-distributed sensor/actuators for active acoustic control.

Aero/structural tailoring of engine blades (AERO/STAEBL)

NASA Technical Reports Server (NTRS)

Brown, K. W.

1988-01-01

This report describes the Aero/Structural Tailoring of Engine Blades (AERO/STAEBL) program, which is a computer code used to perform engine fan and compressor blade aero/structural numerical optimizations. These optimizations seek a blade design of minimum operating cost that satisfies realistic blade design constraints. This report documents the overall program (i.e., input, optimization procedures, approximate analyses) and also provides a detailed description of the validation test cases.

Probabilistic Multi-Scale, Multi-Level, Multi-Disciplinary Analysis and Optimization of Engine Structures

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2000-01-01

Aircraft engines are assemblies of dynamically interacting components. Engine updates to keep present aircraft flying safely and engines for new aircraft are progressively required to operate in more demanding technological and environmental requirements. Designs to effectively meet those requirements are necessarily collections of multi-scale, multi-level, multi-disciplinary analysis and optimization methods and probabilistic methods are necessary to quantify respective uncertainties. These types of methods are the only ones that can formally evaluate advanced composite designs which satisfy those progressively demanding requirements while assuring minimum cost, maximum reliability and maximum durability. Recent research activities at NASA Glenn Research Center have focused on developing multi-scale, multi-level, multidisciplinary analysis and optimization methods. Multi-scale refers to formal methods which describe complex material behavior metal or composite; multi-level refers to integration of participating disciplines to describe a structural response at the scale of interest; multidisciplinary refers to open-ended for various existing and yet to be developed discipline constructs required to formally predict/describe a structural response in engine operating environments. For example, these include but are not limited to: multi-factor models for material behavior, multi-scale composite mechanics, general purpose structural analysis, progressive structural fracture for evaluating durability and integrity, noise and acoustic fatigue, emission requirements, hot fluid mechanics, heat-transfer and probabilistic simulations. Many of these, as well as others, are encompassed in an integrated computer code identified as Engine Structures Technology Benefits Estimator (EST/BEST) or Multi-faceted/Engine Structures Optimization (MP/ESTOP). The discipline modules integrated in MP/ESTOP include: engine cycle (thermodynamics), engine weights, internal fluid mechanics, cost, mission and coupled structural/thermal, various composite property simulators and probabilistic methods to evaluate uncertainty effects (scatter ranges) in all the design parameters. The objective of the proposed paper is to briefly describe a multi-faceted design analysis and optimization capability for coupled multi-discipline engine structures optimization. Results are presented for engine and aircraft type metrics to illustrate the versatility of that capability. Results are also presented for reliability, noise and fatigue to illustrate its inclusiveness. For example, replacing metal rotors with composites reduces the engine weight by 20 percent, 15 percent noise reduction, and an order of magnitude improvement in reliability. Composite designs exist to increase fatigue life by at least two orders of magnitude compared to state-of-the-art metals.

Engineering Encounters: Identifying an Engineering Design Problem

ERIC Educational Resources Information Center

Chizek, Lisa; VanMeeteren, Beth; McDermott, Mark; Uhlenberg, Jill

2018-01-01

Engineering is an intriguing way for students to connect the design process with their knowledge of science (NRC 2012). This article describes the "Engineering a Pancake Recipe" design process which was created to make the structure and properties of matter more meaningful for fifth grade students. The whole pancake recipe engineering…

76 FR 39763 - Special Conditions: Boeing Model 787-8 Airplane; Interaction of Systems and Structures...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

...) Protection, Limit Engine Torque Loads for Sudden Engine Stoppage, and Design Roll Maneuver Requirement AGENCY... design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. These design features include limit engine torque loads for sudden engine...

A probabilistic approach to randomness in geometric configuration of scalable origami structures

NASA Astrophysics Data System (ADS)

Liu, Ke; Paulino, Glaucio; Gardoni, Paolo

2015-03-01

Origami, an ancient paper folding art, has inspired many solutions to modern engineering challenges. The demand for actual engineering applications motivates further investigation in this field. Although rooted from the historic art form, many applications of origami are based on newly designed origami patterns to match the specific requirenments of an engineering problem. The application of origami to structural design problems ranges from micro-structure of materials to large scale deployable shells. For instance, some origami-inspired designs have unique properties such as negative Poisson ratio and flat foldability. However, origami structures are typically constrained by strict mathematical geometric relationships, which in reality, can be easily violated, due to, for example, random imperfections introduced during manufacturing, or non-uniform deformations under working conditions (e.g. due to non-uniform thermal effects). Therefore, the effects of uncertainties in origami-like structures need to be studied in further detail in order to provide a practical guide for scalable origami-inspired engineering designs. Through reliability and probabilistic analysis, we investigate the effect of randomness in origami structures on their mechanical properties. Dislocations of vertices of an origami structure have different impacts on different mechanical properties, and different origami designs could have different sensitivities to imperfections. Thus we aim to provide a preliminary understanding of the structural behavior of some common scalable origami structures subject to randomness in their geometric configurations in order to help transition the technology toward practical applications of origami engineering.

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1992-01-01

ATTAP activities during the past year included test-bed engine design and development, ceramic component design, materials and component characterization, ceramic component process development and fabrication, ceramic component rig testing, and test-bed engine fabrication and testing. Significant technical challenges remain, but all areas exhibited progress. Test-bed engine design and development included engine mechanical design, combustion system design, alternate aerodynamic designs of gasifier scrolls, and engine system integration aimed at upgrading the AGT-5 from a 1038 C (1900 F) metal engine to a durable 1372 C (2500 F) structural ceramic component test-bed engine. ATTAP-defined ceramic and associated ceramic/metal component design activities completed include the ceramic gasifier turbine static structure, the ceramic gasifier turbine rotor, ceramic combustors, the ceramic regenerator disk, the ceramic power turbine rotors, and the ceramic/metal power turbine static structure. The material and component characterization efforts included the testing and evaluation of seven candidate materials and three development components. Ceramic component process development and fabrication proceeded for the gasifier turbine rotor, gasifier turbine scroll, gasifier turbine vanes and vane platform, extruded regenerator disks, and thermal insulation. Component rig activities included the development of both rigs and the necessary test procedures, and conduct of rig testing of the ceramic components and assemblies. Test-bed engine fabrication, testing, and development supported improvements in ceramic component technology that permit the achievement of both program performance and durability goals. Total test time in 1991 amounted to 847 hours, of which 128 hours were engine testing, and 719 were hot rig testing.

Injector tip for an internal combustion engine

DOEpatents

Shyu, Tsu Pin; Ye, Wen

2003-05-20

This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

Similitude design for the vibration problems of plates and shells: A review

NASA Astrophysics Data System (ADS)

Zhu, Yunpeng; Wang, You; Luo, Zhong; Han, Qingkai; Wang, Deyou

2017-06-01

Similitude design plays a vital role in the analysis of vibration and shock problems encountered in large engineering equipment. Similitude design, including dimensional analysis and governing equation method, is founded on the dynamic similitude theory. This study reviews the application of similitude design methods in engineering practice and summarizes the major achievements of the dynamic similitude theory in structural vibration and shock problems in different fields, including marine structures, civil engineering structures, and large power equipment. This study also reviews the dynamic similitude design methods for thin-walled and composite material plates and shells, including the most recent work published by the authors. Structure sensitivity analysis is used to evaluate the scaling factors to attain accurate distorted scaling laws. Finally, this study discusses the existing problems and the potential of the dynamic similitude theory for the analysis of vibration and shock problems of structures.

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fire protection of flight controls, engine...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fire protection of flight controls, engine...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fire protection of flight controls, engine...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fire protection of flight controls, engine...

14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fire protection of flight controls, engine...

Applications of Computer Graphics in Engineering

NASA Technical Reports Server (NTRS)

1975-01-01

Various applications of interactive computer graphics to the following areas of science and engineering were described: design and analysis of structures, configuration geometry, animation, flutter analysis, design and manufacturing, aircraft design and integration, wind tunnel data analysis, architecture and construction, flight simulation, hydrodynamics, curve and surface fitting, gas turbine engine design, analysis, and manufacturing, packaging of printed circuit boards, spacecraft design.

Structural design and analysis of a Mach zero to five turbo-ramjet system

NASA Technical Reports Server (NTRS)

Spoth, Kevin A.; Moses, Paul L.

1993-01-01

The paper discusses the structural design and analysis of a Mach zero to five turbo-ramjet propulsion system for a Mach five waverider-derived cruise vehicle. The level of analysis detail necessary for a credible conceptual design is shown. The results of a finite-element failure mode sizing analysis for the engine primary structure is presented. The importance of engine/airframe integration is also discussed.

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.

Structural integrity of engineering composite materials: a cracking good yarn.

PubMed

Beaumont, Peter W R; Soutis, Costas

2016-07-13

Predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic fracture of the component will occur is one the oldest unsolved mysteries in the design and building of large-scale engineering structures. Where human life depends upon engineering ingenuity, the burden of testing to prove a 'fracture safe design' is immense. Fitness considerations for long-life implementation of large composite structures include understanding phenomena such as impact, fatigue, creep and stress corrosion cracking that affect reliability, life expectancy and durability of structure. Structural integrity analysis treats the design, the materials used, and figures out how best components and parts can be joined, and takes service duty into account. However, there are conflicting aims in the complete design process of designing simultaneously for high efficiency and safety assurance throughout an economically viable lifetime with an acceptable level of risk. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'. © 2016 The Author(s).

Effects of Structural Flexibility on Aircraft-Engine Mounts

NASA Technical Reports Server (NTRS)

Phillips, W. H.

1986-01-01

Analysis extends technique for design of widely used type of vibration-isolating mounts for aircraft engines, in which rubber mounting pads located in plane behind center of gravity of enginepropeller combination. New analysis treats problem in statics. Results of simple approach useful in providing equations for design of vibrationisolating mounts. Equations applicable in usual situation in which engine-mount structure itself relatively light and placed between large mass of engine and other heavy components of airplane.

Engine Structures Modeling Software System (ESMOSS)

NASA Technical Reports Server (NTRS)

1991-01-01

Engine Structures Modeling Software System (ESMOSS) is the development of a specialized software system for the construction of geometric descriptive and discrete analytical models of engine parts, components, and substructures which can be transferred to finite element analysis programs such as NASTRAN. The NASA Lewis Engine Structures Program is concerned with the development of technology for the rational structural design and analysis of advanced gas turbine engines with emphasis on advanced structural analysis, structural dynamics, structural aspects of aeroelasticity, and life prediction. Fundamental and common to all of these developments is the need for geometric and analytical model descriptions at various engine assembly levels which are generated using ESMOSS.

Integration of magnetic bearings in the design of advanced gas turbine engines

NASA Technical Reports Server (NTRS)

Storace, Albert F.; Sood, Devendra K.; Lyons, James P.; Preston, Mark A.

1994-01-01

Active magnetic bearings provide revolutionary advantages for gas turbine engine rotor support. These advantages include tremendously improved vibration and stability characteristics, reduced power loss, improved reliability, fault-tolerance, and greatly extended bearing service life. The marriage of these advantages with innovative structural network design and advanced materials utilization will permit major increases in thrust to weight performance and structural efficiency for future gas turbine engines. However, obtaining the maximum payoff requires two key ingredients. The first key ingredient is the use of modern magnetic bearing technologies such as innovative digital control techniques, high-density power electronics, high-density magnetic actuators, fault-tolerant system architecture, and electronic (sensorless) position estimation. This paper describes these technologies. The second key ingredient is to go beyond the simple replacement of rolling element bearings with magnetic bearings by incorporating magnetic bearings as an integral part of the overall engine design. This is analogous to the proper approach to designing with composites, whereby the designer tailors the geometry and load carrying function of the structural system or component for the composite instead of simply substituting composites in a design originally intended for metal material. This paper describes methodologies for the design integration of magnetic bearings in gas turbine engines.

Summary of engine design and analytical studies to mature the 1137400E engine baseline

NASA Technical Reports Server (NTRS)

Kleinert, D. E.; Lester, W. A.

1972-01-01

Activities in packaging components into integral module arrangements compatible with engine design requirements for the 1137400E flight engine baseline are summarized along with the applied mechanics and thermal analysis. Revisions to drawings, configurations, and support structures are discussed.

The structural approach to shared knowledge: an application to engineering design teams.

PubMed

Avnet, Mark S; Weigel, Annalisa L

2013-06-01

We propose a methodology for analyzing shared knowledge in engineering design teams. Whereas prior work has focused on shared knowledge in small teams at a specific point in time, the model presented here is both scalable and dynamic. By quantifying team members' common views of design drivers, we build a network of shared mental models to reveal the structure of shared knowledge at a snapshot in time. Based on a structural comparison of networks at different points in time, a metric of change in shared knowledge is computed. Analysis of survey data from 12 conceptual space mission design sessions reveals a correlation between change in shared knowledge and each of several system attributes, including system development time, system mass, and technological maturity. From these results, we conclude that an early period of learning and consensus building could be beneficial to the design of engineered systems. Although we do not examine team performance directly, we demonstrate that shared knowledge is related to the technical design and thus provide a foundation for improving design products by incorporating the knowledge and thoughts of the engineering design team into the process.

Design and Structure-Function Characterization of 3D Printed Synthetic Porous Biomaterials for Tissue Engineering.

PubMed

Kelly, Cambre N; Miller, Andrew T; Hollister, Scott J; Guldberg, Robert E; Gall, Ken

2018-04-01

3D printing is now adopted for use in a variety of industries and functions. In biomedical engineering, 3D printing has prevailed over more traditional manufacturing methods in tissue engineering due to its high degree of control over both macro- and microarchitecture of porous tissue scaffolds. However, with the improved flexibility in design come new challenges in characterizing the structure-function relationships between various architectures and both mechanical and biological properties in an assortment of clinical applications. Presently, the field of tissue engineering lacks a comprehensive body of literature that is capable of drawing meaningful relationships between the designed structure and resulting function of 3D printed porous biomaterial scaffolds. This work first discusses the role of design on 3D printed porous scaffold function and then reviews characterization of these structure-function relationships for 3D printed synthetic metallic, polymeric, and ceramic biomaterials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of Creative Problem-Solving Abilities in Undergraduate Structural Engineers through Interdisciplinary Problem-Based Learning

ERIC Educational Resources Information Center

McCrum, Daniel Patrick

2017-01-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs.…

Engineering design in the primary school: applying stem concepts to build an optical instrument

NASA Astrophysics Data System (ADS)

King, Donna; English, Lyn D.

2016-12-01

Internationally there is a need for research that focuses on STEM (Science, Technology, Engineering and Mathematics) education to equip students with the skills needed for a rapidly changing future. One way to do this is through designing engineering activities that reflect real-world problems and contextualise students' learning of STEM concepts. As such, this study examined the learning that occurred when fifth-grade students completed an optical engineering activity using an iterative engineering design model. Through a qualitative methodology using a case study design, we analysed multiple data sources including students' design sketches from eight focus groups. Three key findings emerged: first, the collaborative process of the first design sketch enabled students to apply core STEM concepts to model construction; second, during the construction stage students used experimentation for the positioning of lenses, mirrors and tubes resulting in a simpler 'working' model; and third, the redesign process enabled students to apply structural changes to their design. The engineering design model was useful for structuring stages of design, construction and redesign; however, we suggest a more flexible approach for advanced applications of STEM concepts in the future.

Ceramic automotive Stirling engine study

NASA Technical Reports Server (NTRS)

Musikant, S.; Chiu, W.; Darooka, D.; Mullings, D. M.; Johnson, C. A.

1985-01-01

A conceptual design study for a Ceramic Automotive Stirling Engine (CASE) is performed. Year 1990 structural ceramic technology is assumed. Structural and performance analyses of the conceptual design are performed as well as a manufacturing and cost analysis. The general conclusions from this study are that such an engine would be 10-26% more efficient over its performance map than the current metal Automotive Stirling Reference Engine (ASRE). Cost of such a ceramic engine is likely to be somewhat higher than that of the ASRE but engine cost is very sensitive to the ultimate cost of the high purity, ceramic powder raw materials required to fabricate high performance parts. When the design study is projected to the year 2000 technology, substantinal net efficiency improvements, on the order of 25 to 46% over the ASRE, are computed.

Structural tailoring of engine blades (STAEBL) user's manual

NASA Technical Reports Server (NTRS)

Brown, K. W.

1985-01-01

This User's Manual contains instructions and demonstration case to prepare input data, run, and modify the Structural Tailoring of Engine Blades (STAEBL) computer code. STAEBL was developed to perform engine fan and compressor blade numerical optimizations. This blade optimization seeks a minimum weight or cost design that satisfies realistic blade design constraints, by tuning one to twenty design variables. The STAEBL constraint analyses include blade stresses, vibratory response, flutter, and foreign object damage. Blade design variables include airfoil thickness at several locations, blade chord, and construction variables: hole size for hollow blades, and composite material layup for composite blades.

Cryogenic Technology, part 1. [conference proceedings; cryogenic wind tunnel design and instrumentation

NASA Technical Reports Server (NTRS)

1980-01-01

Different engineering problems associated with the design of mechanisms and systems to operate in a cryogenic environment are discussed. The focal point for the entire engineering effort was the design of the National Transonic Facility, which is a closed-circuit cryogenic wind tunnel. The papers covered a variety of mechanical, structural, and systems design subjects including thermal structures insulation systems, noise, seals, and materials.

Computational Infrastructure for Engine Structural Performance Simulation

NASA Technical Reports Server (NTRS)

Chamis, Christos C.

1997-01-01

Select computer codes developed over the years to simulate specific aspects of engine structures are described. These codes include blade impact integrated multidisciplinary analysis and optimization, progressive structural fracture, quantification of uncertainties for structural reliability and risk, benefits estimation of new technology insertion and hierarchical simulation of engine structures made from metal matrix and ceramic matrix composites. Collectively these codes constitute a unique infrastructure readiness to credibly evaluate new and future engine structural concepts throughout the development cycle from initial concept, to design and fabrication, to service performance and maintenance and repairs, and to retirement for cause and even to possible recycling. Stated differently, they provide 'virtual' concurrent engineering for engine structures total-life-cycle-cost.

Quiet Clean Short-haul Experimental Engine (QCSEE). Composite fan frame subsystem test report

NASA Technical Reports Server (NTRS)

Stotler, C. L., Jr.; Bowden, J. H.

1977-01-01

The element and subcomponent testing conducted to verify the composite fan frame design of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft is described. Emphasis is placed on the propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing, including technology in composite structures and digital engine controls. The element tests confirmed that the processes used in the frame design would produce the predicted mechanical properties. The subcomponent tests verified that the detail structural components of the frame had adequate structural integrity.

Visit from JAXA to NASA MSFC: The Engines Element & Ideas for Collaboration

NASA Technical Reports Server (NTRS)

Greene, William D.

2013-01-01

System Design, Development, and Fabrication: Design, develop, and fabricate or procure MB-60 component hardware compliant with the imposed technical requirements and in sufficient quantities to fulfill the overall MB-60 development effort. System Development, Assembly, and Test: Manage the scope of the development, assembly, and test-related activities for MB-60 development. This scope includes engine-level development planning, engine assembly and disassembly, test planning, engine testing, inspection, anomaly resolution, and development of necessary ground support equipment and special test equipment. System Integration: Provide coordinated integration in the realms of engineering, safety, quality, and manufacturing disciplines across the scope of the MB-60 design and associated products development Safety and Mission Assurance, structural design, fracture control, materials and processes, thermal analysis. Systems Engineering and Analysis: Manage and perform Systems Engineering and Analysis to provide rigor and structure to the overall design and development effort for the MB-60. Milestone reviews, requirements management, system analysis, program management support Program Management: Manage, plan, and coordinate the activities across all portions of the MB-60 work scope by providing direction for program administration, business management, and supplier management.

Energy efficient engine fan component detailed design report

NASA Technical Reports Server (NTRS)

Halle, J. E.; Michael, C. J.

1981-01-01

The fan component which was designed for the energy efficient engine is an advanced high performance, single stage system and is based on technology advancements in aerodynamics and structure mechanics. Two fan components were designed, both meeting the integrated core/low spool engine efficiency goal of 84.5%. The primary configuration, envisioned for a future flight propulsion system, features a shroudless, hollow blade and offers a predicted efficiency of 87.3%. A more conventional blade was designed, as a back up, for the integrated core/low spool demonstrator engine. The alternate blade configuration has a predicted efficiency of 86.3% for the future flight propulsion system. Both fan configurations meet goals established for efficiency surge margin, structural integrity and durability.

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1990-01-01

Advanced Turbine Technology Application Project (ATTAP) activities during the past year were highlighted by test-bed engine design and development activities; ceramic component design; materials and component characterization; ceramic component process development and fabrication; component rig testing; and test-bed engine fabrication and testing. Although substantial technical challenges remain, all areas exhibited progress. Test-bed engine design and development activity included engine mechanical design, power turbine flow-path design and mechanical layout, and engine system integration aimed at upgrading the AGT-5 from a 1038 C metal engine to a durable 1371 C structural ceramic component test-bed engine. ATTAP-defined ceramic and associated ceramic/metal component design activities include: the ceramic combustor body, the ceramic gasifier turbine static structure, the ceramic gasifier turbine rotor, the ceramic/metal power turbine static structure, and the ceramic power turbine rotors. The materials and component characterization efforts included the testing and evaluation of several candidate ceramic materials and components being developed for use in the ATTAP. Ceramic component process development and fabrication activities are being conducted for the gasifier turbine rotor, gasifier turbine vanes, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Component rig testing activities include the development of the necessary test procedures and conduction of rig testing of the ceramic components and assemblies. Four-hundred hours of hot gasifier rig test time were accumulated with turbine inlet temperatures exceeding 1204 C at 100 percent design gasifier speed. A total of 348.6 test hours were achieved on a single ceramic rotor without failure and a second ceramic rotor was retired in engine-ready condition at 364.9 test hours. Test-bed engine fabrication, testing, and development supported improvements in ceramic component technology that will permit the achievement of program performance and durability goals. The designated durability engine accumulated 359.3 hour of test time, 226.9 of which were on the General Motors gas turbine durability schedule.

Design, Progressive Modeling, Manufacture, and Testing of Composite Shield for Turbine Engine Blade Containment

NASA Technical Reports Server (NTRS)

Binienda, Wieslaw K.; Sancaktar, Erol; Roberts, Gary D. (Technical Monitor)

2002-01-01

An effective design methodology was established for composite jet engine containment structures. The methodology included the development of the full and reduced size prototypes, and FEA models of the containment structure, experimental and numerical examination of the modes of failure clue to turbine blade out event, identification of materials and design candidates for future industrial applications, and design and building of prototypes for testing and evaluation purposes.

Camera Layout Design for the Upper Stage Thrust Cone

NASA Technical Reports Server (NTRS)

Wooten, Tevin; Fowler, Bart

2010-01-01

Engineers in the Integrated Design and Analysis Division (EV30) use a variety of different tools to aid in the design and analysis of the Ares I vehicle. One primary tool in use is Pro-Engineer. Pro-Engineer is a computer-aided design (CAD) software that allows designers to create computer generated structural models of vehicle structures. For the Upper State thrust cone, Pro-Engineer was used to assist in the design of a layout for two camera housings. These cameras observe the separation between the first and second stage of the Ares I vehicle. For the Ares I-X, one standard speed camera was used. The Ares I design calls for two separate housings, three cameras, and a lighting system. With previous design concepts and verification strategies in mind, a new layout for the two camera design concept was developed with members of the EV32 team. With the new design, Pro-Engineer was used to draw the layout to observe how the two camera housings fit with the thrust cone assembly. Future analysis of the camera housing design will verify the stability and clearance of the camera with other hardware present on the thrust cone.

14 CFR Appendix A to Part 23 - Simplified Design Load Criteria

Code of Federal Regulations, 2012 CFR

2012-01-01

... imposed when the particular items are installed in the airplane. The engine mount, however, must be.... (d) Supplementary conditions; rear lift truss; engine torque; side load on engine mount. Each of the... weight. (2) Each engine mount and its supporting structures must be designed for the maximum limit torque...

14 CFR Appendix A to Part 23 - Simplified Design Load Criteria

Code of Federal Regulations, 2014 CFR

2014-01-01

... imposed when the particular items are installed in the airplane. The engine mount, however, must be.... (d) Supplementary conditions; rear lift truss; engine torque; side load on engine mount. Each of the... weight. (2) Each engine mount and its supporting structures must be designed for the maximum limit torque...

14 CFR Appendix A to Part 23 - Simplified Design Load Criteria

Code of Federal Regulations, 2013 CFR

2013-01-01

... imposed when the particular items are installed in the airplane. The engine mount, however, must be.... (d) Supplementary conditions; rear lift truss; engine torque; side load on engine mount. Each of the... weight. (2) Each engine mount and its supporting structures must be designed for the maximum limit torque...

Collaborative engineering-design support system

NASA Technical Reports Server (NTRS)

Lee, Dong HO; Decker, D. Richard

1994-01-01

Designing engineering objects requires many engineers' knowledge from different domains. There needs to be cooperative work among engineering designers to complete a design. Revisions of a design are time consuming, especially if designers work at a distance and with different design description formats. In order to reduce the design cycle, there needs to be a sharable design describing the engineering community, which can be electronically transportable. Design is a process of integrating that is not easy to define definitively. This paper presents Design Script which is a generic engineering design knowledge representation scheme that can be applied in any engineering domain. The Design Script is developed through encapsulation of common design activities and basic design components based on problem decomposition. It is implemented using CLIPS with a Windows NT graphical user interface. The physical relationships between engineering objects and their subparts can be constructed in a hierarchical manner. The same design process is repeatedly applied at each given level of hierarchy and recursively into lower levels of the hierarchy. Each class of the structure can be represented using the Design Script.

Digital design of scaffold for mandibular defect repair based on tissue engineering*

PubMed Central

Liu, Yun-feng; Zhu, Fu-dong; Dong, Xing-tao; Peng, Wei

2011-01-01

Mandibular defect occurs more frequently in recent years, and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws. Tissue engineering, which is a hot research field of biomedical engineering, provides a new direction for mandibular defect repair. As the basis and key part of tissue engineering, scaffolds have been widely and deeply studied in regards to the basic theory, as well as the principle of biomaterial, structure, design, and fabrication method. However, little research is targeted at tissue regeneration for clinic repair operations. Since mandibular bone has a special structure, rather than uniform and regular structure in existing studies, a methodology based on tissue engineering is proposed for mandibular defect repair in this paper. Key steps regarding scaffold digital design, such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail. By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping, the feasibility and effectiveness of the proposed methodology are properly verified. More works about mechanical and biological improvements need to be done to promote its clinical application in future. PMID:21887853

Digital design of scaffold for mandibular defect repair based on tissue engineering.

PubMed

Liu, Yun-feng; Zhu, Fu-dong; Dong, Xing-tao; Peng, Wei

2011-09-01

Mandibular defect occurs more frequently in recent years, and clinical repair operations via bone transplantation are difficult to be further improved due to some intrinsic flaws. Tissue engineering, which is a hot research field of biomedical engineering, provides a new direction for mandibular defect repair. As the basis and key part of tissue engineering, scaffolds have been widely and deeply studied in regards to the basic theory, as well as the principle of biomaterial, structure, design, and fabrication method. However, little research is targeted at tissue regeneration for clinic repair operations. Since mandibular bone has a special structure, rather than uniform and regular structure in existing studies, a methodology based on tissue engineering is proposed for mandibular defect repair in this paper. Key steps regarding scaffold digital design, such as external shape design and internal microstructure design directly based on triangular meshes are discussed in detail. By analyzing the theoretical model and the measured data from the test parts fabricated by rapid prototyping, the feasibility and effectiveness of the proposed methodology are properly verified. More works about mechanical and biological improvements need to be done to promote its clinical application in future.

Integrated analysis of engine structures

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1981-01-01

The need for light, durable, fuel efficient, cost effective aircraft requires the development of engine structures which are flexible, made from advaced materials (including composites), resist higher temperatures, maintain tighter clearances and have lower maintenance costs. The formal quantification of any or several of these requires integrated computer programs (multilevel and/or interdisciplinary analysis programs interconnected) for engine structural analysis/design. Several integrated analysis computer prorams are under development at Lewis Reseach Center. These programs include: (1) COBSTRAN-Composite Blade Structural Analysis, (2) CODSTRAN-Composite Durability Structural Analysis, (3) CISTRAN-Composite Impact Structural Analysis, (4) STAEBL-StruTailoring of Engine Blades, and (5) ESMOSS-Engine Structures Modeling Software System. Three other related programs, developed under Lewis sponsorship, are described.

Chapter D. The Loma Prieta, California, Earthquake of October 17, 1989 - Earth Structures and Engineering Characterization of Ground Motion

USGS Publications Warehouse

Holzer, Thomas L.

1998-01-01

This chapter contains two papers that summarize the performance of engineered earth structures, dams and stabilized excavations in soil, and two papers that characterize for engineering purposes the attenuation of ground motion with distance during the Loma Prieta earthquake. Documenting the field performance of engineered structures and confirming empirically based predictions of ground motion are critical for safe and cost effective seismic design of future structures as well as the retrofitting of existing ones.

Activities report of the Department of Engineering

NASA Astrophysics Data System (ADS)

Acoustics, aerodynamics, fluid mechanics, design, electrical, materials science, mechanical, control, robotics, soil mechanics, structural engineering, thermodynamics, and turbomachine engineering research are described.

VIPR III VADR SPIDER Structural Design and Analysis

NASA Technical Reports Server (NTRS)

Li, Wesley; Chen, Tony

2016-01-01

In support of the National Aeronautics and Space Administration (NASA) Vehicle Integrated Propulsion Research (VIPR) Phase III team to evaluate the volcanic ash environment effects on the Pratt & Whitney F117-PW-100 turbofan engine, NASA Armstrong Flight Research Center has successfully performed structural design and analysis on the Volcanic Ash Distribution Rig (VADR) and the Structural Particulate Integration Device for Engine Research (SPIDER) for the ash ingestion test. Static and dynamic load analyses were performed to ensure no structural failure would occur during the test. Modal analysis was conducted, and the results were used to develop engine power setting avoidance zones. These engine power setting avoidance zones were defined to minimize the dwell time when the natural frequencies of the VADR/SPIDER system coincided with the excitation frequencies of the engine which was operating at various revolutions per minute. Vortex-induced vibration due to engine suction air flow during the ingestion test was also evaluated, but was not a concern.

Structural Test Laboratory | Water Power | NREL

Science.gov Websites

Structural Test Laboratory Structural Test Laboratory NREL engineers design and configure structural components can validate models, demonstrate system reliability, inform design margins, and assess , including mass and center of gravity, to ensure compliance with design goals Dynamic Characterization Use

Contextual Shaping of Student Design Practices: The Role of Constraint in First-Year Engineering Design

NASA Astrophysics Data System (ADS)

Goncher, Andrea M.

thResearch on engineering design is a core area of concern within engineering education, and a fundamental understanding of how engineering students approach and undertake design is necessary in order to develop effective design models and pedagogies. This dissertation contributes to scholarship on engineering design by addressing a critical, but as yet underexplored, problem: how does the context in which students design shape their design practices? Using a qualitative study comprising of video data of design sessions, focus group interviews with students, and archives of their design work, this research explored how design decisions and actions are shaped by context, specifically the context of higher education. To develop a theoretical explanation for observed behavior, this study used the nested structuration. framework proposed by Perlow, Gittell, & Katz (2004). This framework explicated how teamwork is shaped by mutually reinforcing relationships at the individual, organizational, and institutional levels. I appropriated this framework to look specifically at how engineering students working on a course-related design project identify constraints that guide their design and how these constraints emerge as students interact while working on the project. I first identified and characterized the parameters associated with the design project from the student perspective and then, through multi-case studies of four design teams, I looked at the role these parameters play in student design practices. This qualitative investigation of first-year engineering student design teams revealed mutual and interconnected relationships between students and the organizations and institutions that they are a part of. In addition to contributing to research on engineering design, this work provides guidelines and practices to help design educators develop more effective design projects by incorporating constraints that enable effective design and learning. Moreover, I found that when appropriated in the context of higher education, multiple sublevels existed within nested structuration's organizational context and included course-level and project-level factors. The implications of this research can be used to improve the design of engineering course projects as well as the design of research efforts related to design in engineering education.

Preliminary scramjet design for hypersonic airbreathing missile application

NASA Technical Reports Server (NTRS)

Carlson, C. H.

1983-01-01

A conceptual design study of a scramjet engine was conducted for a hypersonic surface to air missile (HYSAM). The definition of the engine was based upon the requirements of accelerating the HYSAM from Mach 4 at 20,000 feet to Mach 6 at 100,000 feet and the cruise conditions at Mach 6. The resulting external and internal environmental conditions were used by various engineering disciplines performing design, stress and heat transfer analysis. A detailed structural analysis was conducted along with an indepth thermal analysis. Structurally all the components within the system exhibit positive margins of safety. A feasible concept was defined which uses state-of-the-art materials and existing TMC technology. The engine basically consists of a three dimensional carbon/carbon combustor/nozzle secured to an FS-85 columbium inlet. The carbon/carbon liner is sheathed with carbon felt insulation to thermally protect the FS-85 structure and skin. The thermal analysis of the engine indicates that a thermally viable configuration exists.

System Re-engineering Project Executive Summary

DTIC Science & Technology

1991-11-01

Management Information System (STAMIS) application. This project involved reverse engineering, evaluation of structured design and object-oriented design, and re- implementation of the system in Ada. This executive summary presents the approach to re-engineering the system, the lessons learned while going through the process, and issues to be considered in future tasks of this nature.... Computer-Aided Software Engineering (CASE), Distributed Software, Ada, COBOL, Systems Analysis, Systems Design, Life Cycle Development, Functional Decomposition, Object-Oriented

Use of Concurrent Engineering in Space Mission Design

NASA Technical Reports Server (NTRS)

Wall, S.

2000-01-01

In recent years, conceptual-phase (proposal level) design of space missions has been improved considerably. Team structures, tool linkage, specialized facilities known as design centers and scripted processes have been demonstrated to cut proposal-level engineering design time from a few months to a few weeks.

Thermal/Structural Tailoring of Engine Blades (T/STAEBL) User's manual

NASA Technical Reports Server (NTRS)

Brown, K. W.

1994-01-01

The Thermal/Structural Tailoring of Engine Blades (T/STAEBL) system is a computer code that is able to perform numerical optimizations of cooled jet engine turbine blades and vanes. These optimizations seek an airfoil design of minimum operating cost that satisfies realistic design constraints. This report documents the organization of the T/STAEBL computer program, its design and analysis procedure, its optimization procedure, and provides an overview of the input required to run the program, as well as the computer resources required for its effective use. Additionally, usage of the program is demonstrated through a validation test case.

Thermal/Structural Tailoring of Engine Blades (T/STAEBL): User's manual

NASA Astrophysics Data System (ADS)

Brown, K. W.

1994-03-01

The Thermal/Structural Tailoring of Engine Blades (T/STAEBL) system is a computer code that is able to perform numerical optimizations of cooled jet engine turbine blades and vanes. These optimizations seek an airfoil design of minimum operating cost that satisfies realistic design constraints. This report documents the organization of the T/STAEBL computer program, its design and analysis procedure, its optimization procedure, and provides an overview of the input required to run the program, as well as the computer resources required for its effective use. Additionally, usage of the program is demonstrated through a validation test case.

Combined protein construct and synthetic gene engineering for heterologous protein expression and crystallization using Gene Composer

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

Raymond, Amy; Lovell, Scott; Lorimer, Don

2009-12-01

With the goal of improving yield and success rates of heterologous protein production for structural studies we have developed the database and algorithm software package Gene Composer. This freely available electronic tool facilitates the information-rich design of protein constructs and their engineered synthetic gene sequences, as detailed in the accompanying manuscript. In this report, we compare heterologous protein expression levels from native sequences to that of codon engineered synthetic gene constructs designed by Gene Composer. A test set of proteins including a human kinase (P38{alpha}), viral polymerase (HCV NS5B), and bacterial structural protein (FtsZ) were expressed in both E. colimore » and a cell-free wheat germ translation system. We also compare the protein expression levels in E. coli for a set of 11 different proteins with greatly varied G:C content and codon bias. The results consistently demonstrate that protein yields from codon engineered Gene Composer designs are as good as or better than those achieved from the synonymous native genes. Moreover, structure guided N- and C-terminal deletion constructs designed with the aid of Gene Composer can lead to greater success in gene to structure work as exemplified by the X-ray crystallographic structure determination of FtsZ from Bacillus subtilis. These results validate the Gene Composer algorithms, and suggest that using a combination of synthetic gene and protein construct engineering tools can improve the economics of gene to structure research.« less

A real-time all-atom structural search engine for proteins.

PubMed

Gonzalez, Gabriel; Hannigan, Brett; DeGrado, William F

2014-07-01

Protein designers use a wide variety of software tools for de novo design, yet their repertoire still lacks a fast and interactive all-atom search engine. To solve this, we have built the Suns program: a real-time, atomic search engine integrated into the PyMOL molecular visualization system. Users build atomic-level structural search queries within PyMOL and receive a stream of search results aligned to their query within a few seconds. This instant feedback cycle enables a new "designability"-inspired approach to protein design where the designer searches for and interactively incorporates native-like fragments from proven protein structures. We demonstrate the use of Suns to interactively build protein motifs, tertiary interactions, and to identify scaffolds compatible with hot-spot residues. The official web site and installer are located at http://www.degradolab.org/suns/ and the source code is hosted at https://github.com/godotgildor/Suns (PyMOL plugin, BSD license), https://github.com/Gabriel439/suns-cmd (command line client, BSD license), and https://github.com/Gabriel439/suns-search (search engine server, GPLv2 license).

Development and Application of a Systems Engineering Framework to Support Online Course Design and Delivery

ERIC Educational Resources Information Center

Bozkurt, Ipek; Helm, James

2013-01-01

This paper develops a systems engineering-based framework to assist in the design of an online engineering course. Specifically, the purpose of the framework is to provide a structured methodology for the design, development and delivery of a fully online course, either brand new or modified from an existing face-to-face course. The main strength…

On the Problems of Cracking and the Question of Structural Integrity of Engineering Composite Materials

NASA Astrophysics Data System (ADS)

Beaumont, Peter W. R.

2014-02-01

Predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic fracture of the component will occur is one the oldest unsolved mysteries in the design and building of large engineering structures. Where human life depends upon engineering ingenuity, the burden of testing to prove a "fracture safe design" is immense. For example, when human life depends upon structural integrity as an essential design requirement, it takes ten thousand material test coupons per composite laminate configuration to evaluate an airframe plus loading to ultimate failure tails, wing boxes, and fuselages to achieve a commercial aircraft airworthiness certification. Fitness considerations for long-life implementation of aerospace composites include understanding phenomena such as impact, fatigue, creep, and stress corrosion cracking that affect reliability, life expectancy, and durability of structure. Structural integrity analysis treats the design, the materials used, and figures out how best components and parts can be joined. Furthermore, SI takes into account service duty. However, there are conflicting aims in the complete design process of designing simultaneously for high efficiency and safety assurance throughout an economically viable lifetime with an acceptable level of risk.

Engineering Design EDUCATION: When, What, and HOW

ERIC Educational Resources Information Center

Khalaf, Kinda; Balawi, Shadi; Hitt, George Wesley; Radaideh, Ahmad

2013-01-01

This paper presents an innovative, interdisciplinary, design-and-build course created to improve placement, content, and pedagogy for introductory engineering design education. Infused at the freshman level, the course aims to promote expert design thinking by using problem-based learning (PBL) as the mode of delivery. The course is structured to…

Low-thrust chemical rocket engine study

NASA Technical Reports Server (NTRS)

Mellish, J. A.

1981-01-01

Engine data and information are presented to perform system studies on cargo orbit-transfer vehicles which would deliver large space structures to geosynchronous equatorial orbit. Low-thrust engine performance, weight, and envelope parametric data were established, preliminary design information was generated, and technologies for liquid rocket engines were identified. Two major engine design drivers were considered in the study: cooling and engine cycle options. Both film-cooled and regeneratively cooled engines were evaluated. The propellant combinations studied were hydrogen/oxygen, methane/oxygen, and kerosene/oxygen.

Protein-based hydrogels for tissue engineering

PubMed Central

Schloss, Ashley C.; Williams, Danielle M.; Regan, Lynne J.

2017-01-01

The tunable mechanical and structural properties of protein-based hydrogels make them excellent scaffolds for tissue engineering and repair. Moreover, using protein-based components provides the option to insert sequences associated with the promoting both cellular adhesion to the substrate and overall cell growth. Protein-based hydrogel components are appealing for their structural designability, specific biological functionality, and stimuli-responsiveness. Here we present highlights in the field of protein-based hydrogels for tissue engineering applications including design requirements, components, and gel types. PMID:27677513

Structural design of Stirling engine with free pistons

NASA Astrophysics Data System (ADS)

Matusov, Jozef; Gavlas, Stanislav; Malcho, Milan

2014-08-01

Stirling engine is a device that converts thermal energy to mechanical work, which is mostly used to drive a generator of electricity. Advantage of Stirling engine is that it works with closed-cycle, where working medium is regularly cooled and heated, which acts on the working piston. This engine can be made in three modifications - alpha, beta, gamma. This paper discusses the design of the gamma Stirling engine with free pistons.

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.

PIV measurements of in-cylinder, large-scale structures in a water-analogue Diesel engine

NASA Astrophysics Data System (ADS)

Kalpakli Vester, A.; Nishio, Y.; Alfredsson, P. H.

2016-11-01

Swirl and tumble are large-scale structures that develop in an engine cylinder during the intake stroke. Their structure and strength depend on the design of the inlet ports and valves, but also on the valve lift history. Engine manufacturers make their design to obtain a specific flow structure that is assumed to give the best engine performance. Despite many efforts, there are still open questions, such as how swirl and tumble depend on the dynamics of the valves/piston as well as how cycle-to-cycle variations should be minimized. In collaboration with Swedish vehicle industry we perform PIV measurements of the flow dynamics during the intake stroke inside a cylinder of a water-analogue engine model having the same geometrical characteristics as a typical truck Diesel engine. Water can be used since during the intake stroke the flow is nearly incompressible. The flow from the valves moves radially outwards, hits the vertical walls of the cylinder, entrains surrounding fluid, moves along the cylinder walls and creates a central backflow, i.e. a tumble motion. Depending on the port and valve design and orientation none, low, or high swirl can be established. For the first time, the effect of the dynamic motion of the piston/valves on the large-scale structures is captured. Supported by the Swedish Energy Agency, Scania CV AB and Volvo GTT, through the FFI program.

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2011 CFR

2011-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

14 CFR 29.549 - Fuselage and rotor pylon structures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) [Reserved] (e) If approval for the use of 21/2-minute OEI power is requested, each engine...

Quiet Clean Short-haul Experimental Engine (QCSEE) Over The Wing (OTW) design report

NASA Technical Reports Server (NTRS)

1977-01-01

The design, fabrication, and testing of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft are described. The propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing is demonstrated. Composite structures and digital engine controls are among the topics included.

Detailed Post-Soft Impact Progressive Damage Assessment for Hybrid Structure Jet Engines

NASA Technical Reports Server (NTRS)

Siddens, Aaron; Bayandor, Javid; Celestina, Mark L.

2014-01-01

Currently, certification of engine designs for resistance to bird strike is reliant on physical tests. Predictive modeling of engine structural damage has mostly been limited to evaluation of individual forward section components, such as fan blades within a fixed frame of reference, to direct impact with a bird. Such models must be extended to include interactions among engine components under operating conditions to evaluate the full extent of engine damage. This paper presents the results of a study aim to develop a methodology for evaluating bird strike damage in advanced propulsion systems incorporating hybrid composite/metal structures. The initial degradation and failure of individual fan blades struck by a bird were investigated. Subsequent damage to other fan blades and engine components due to resultant violent fan assembly vibrations and fragmentation was further evaluated. Various modeling parameters for the bird and engine components were investigated to determine guidelines for accurately capturing initial damage and progressive failure of engine components. Then, a novel hybrid structure modeling approach was investigated and incorporated into the crashworthiness methodology. Such a tool is invaluable to the process of design, development, and certification of future advanced propulsion systems.

Estimating design discharges for drainage structures in western Kansas.

DOT National Transportation Integrated Search

2013-06-01

KDOT engineers have expressed concern that the hydrologic methods in the current KDOT Design Manual (Volume I, : Part C, 2011) may lead to over-sizing of drainage structures in Western Kansas. Some new structures designed by the current : methods are...

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1989-01-01

ATTAP activities during the past year were highlighted by an extensive materials assessment, execution of a reference powertrain design, test-bed engine design and development, ceramic component design, materials and component characterization, ceramic component process development and fabrication, component rig design and fabrication, test-bed engine fabrication, and hot gasifier rig and engine testing. Materials assessment activities entailed engine environment evaluation of domestically supplied radial gasifier turbine rotors that were available at the conclusion of the Advanced Gas Turbine (AGT) Technology Development Project as well as an extensive survey of both domestic and foreign ceramic suppliers and Government laboratories performing ceramic materials research applicable to advanced heat engines. A reference powertrain design was executed to reflect the selection of the AGT-5 as the ceramic component test-bed engine for the ATTAP. Test-bed engine development activity focused on upgrading the AGT-5 from a 1038 C (1900 F) metal engine to a durable 1371 C (2500 F) structural ceramic component test-bed engine. Ceramic component design activities included the combustor, gasifier turbine static structure, and gasifier turbine rotor. The materials and component characterization efforts have included the testing and evaluation of several candidate ceramic materials and components being developed for use in the ATTAP. Ceramic component process development and fabrication activities were initiated for the gasifier turbine rotor, gasifier turbine vanes, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Component rig development activities included combustor, hot gasifier, and regenerator rigs. Test-bed engine fabrication activities consisted of the fabrication of an all-new AGT-5 durability test-bed engine and support of all engine test activities through instrumentation/build/repair. Hot gasifier rig and test-bed engine testing activities were performed.

Evolutionary and biological metaphors for engineering design

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

Jakiela, M.

1994-12-31

Since computing became generally available, there has been strong interest in using computers to assist and automate engineering design processes. Specifically, for design optimization and automation, nonlinear programming and artificial intelligence techniques have been extensively studied. New computational techniques, based upon the natural processes of evolution, adaptation, and learing, are showing promise because of their generality and robustness. This presentation will describe the use of two such techniques, genetic algorithms and classifier systems, for a variety of engineering design problems. Structural topology optimization, meshing, and general engineering optimization are shown as example applications.

Structural Optimization Methodology for Rotating Disks of Aircraft Engines

NASA Technical Reports Server (NTRS)

Armand, Sasan C.

1995-01-01

In support of the preliminary evaluation of various engine technologies, a methodology has been developed for structurally designing the rotating disks of an aircraft engine. The structural design methodology, along with a previously derived methodology for predicting low-cycle fatigue life, was implemented in a computer program. An interface computer program was also developed that gathers the required data from a flowpath analysis program (WATE) being used at NASA Lewis. The computer program developed for this study requires minimum interaction with the user, thus allowing engineers with varying backgrounds in aeropropulsion to successfully execute it. The stress analysis portion of the methodology and the computer program were verified by employing the finite element analysis method. The 10th- stage, high-pressure-compressor disk of the Energy Efficient Engine Program (E3) engine was used to verify the stress analysis; the differences between the stresses and displacements obtained from the computer program developed for this study and from the finite element analysis were all below 3 percent for the problem solved. The computer program developed for this study was employed to structurally optimize the rotating disks of the E3 high-pressure compressor. The rotating disks designed by the computer program in this study were approximately 26 percent lighter than calculated from the E3 drawings. The methodology is presented herein.

Expert System Approach For Generating And Evaluating Engine Design Alternatives

NASA Astrophysics Data System (ADS)

Shen, Stewart N. T.; Chew, Meng-Sang; Issa, Ghassan F.

1989-03-01

Artificial intelligence is becoming an increasingly important subject of study for computer scientists, engineering designers, as well as professionals in other fields. Even though AI technology is a relatively new discipline, many of its concepts have already found practical applications. Expert systems, in particular, have made significant contributions to technologies in such fields as business, medicine, engineering design, chemistry, and particle physics. This paper describes an expert system developed to aid the mechanical designer with the preliminary design of variable-stroke internal-combustion engines. The expert system accomplished its task by generating and evaluating a large number of design alternatives represented in the form of graphs. Through the application of structural and design rules directly to the graphs, optimal and near optimal preliminary design configurations of engines are deduced.

Structure and Management of an Engineering Senior Design Course.

PubMed

Tanaka, Martin L; Fischer, Kenneth J

2016-07-01

The design of products and processes is an important area in engineering. Students in engineering schools learn fundamental principles in their courses but often lack an opportunity to apply these methods to real-world problems until their senior year. This article describes important elements that should be incorporated into a senior capstone design course. It includes a description of the general principles used in engineering design and a discussion of why students often have difficulty with application and revert to trial and error methods. The structure of a properly designed capstone course is dissected and its individual components are evaluated. Major components include assessing resources, identifying projects, establishing teams, understanding requirements, developing conceptual designs, creating detailed designs, building prototypes, testing performance, and final presentations. In addition to the course design, team management and effective mentoring are critical to success. This article includes suggested guidelines and tips for effective design team leadership, attention to detail, investment of time, and managing project scope. Furthermore, the importance of understanding business culture, displaying professionalism, and considerations of different types of senior projects is discussed. Through a well-designed course and proper mentoring, students will learn to apply their engineering skills and gain basic business knowledge that will prepare them for entry-level positions in industry.

Liquid rocket engine combustion stabilization devices

NASA Technical Reports Server (NTRS)

1974-01-01

Combustion instability, which results from a coupling of the combustion process and the fluid dynamics of the engine system, was investigated. The design of devices which reduce coupling (combustion chamber baffles) and devices which increase damping (acoustic absorbers) are described. Included in the discussion are design criteria and recommended practices, structural and mechanical design, thermal control, baffle geometry, baffle/engine interactions, acoustic damping analysis, and absorber configurations.

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

Neitzel, D.A.; McKenzie, D.H.

To minimize adverse impact on aquatic ecosystems resulting from the operation of water intake structures, design engineers must have relevant information on the behavior, physiology and ecology of local fish and shellfish. Identification of stimulus/response relationships and the environmental factors that influence them is the first step in incorporating biological information in the design, location or modification of water intake structures. A procedure is presented in this document for providing biological input to engineers who are designing, locating or modifying a water intake structure. The authors discuss sources of stimuli at water intakes, historical approaches in assessing potential/actual impact andmore » review biological information needed for intake design.« less

Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

NASA Technical Reports Server (NTRS)

Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

1994-01-01

A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

Low Density Materials

DTIC Science & Technology

2012-03-09

materials structures across scales for design of engineered systems ODISSEI: Origami Design for Integration of Self-assembling Systems for...AGENCIES Origami Engineering US-India Tunable Materials Forum US-AFRICA Initiative Reliance 21 Board Materials and Processing COI 29 DISTRIBUTION A

Estimating design discharges for drainage structures in western Kansas : [summary].

DOT National Transportation Integrated Search

2013-06-01

KDOT engineers have expressed concern that the hydrologic methods in the current KDOT Design Manual (Volume I, Part C, 2011) may lead to over-sizing of drainage structures in Western Kansas. Some new structures designed by the current methods are muc...

Railway vehicle body structures

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

Not Available

1985-01-01

The strength and durability of railway vehicle structures is a major topic of engineering research and design. To reflect this importance the Railway Division of the Institution of Mechanical Engineers organised a conference to discuss all matters relating to railway vehicle design. This book presents the papers discussed in that conference. The contents include: Vehicle body design and the UIC's international contribution; LUL prototype 1986 stock - body structure; vehicle structure for the intermediate capacity transmit system vehicles; car body technology of advanced light rapid transit vehicles; concepts, techniques and experience in the idealization of car body structures for finitemore » element analysis; Calcutta metropolitan railway; design for a lightweight diesel multiple unit body; the design of lightweight inter-city coal structures; the BREL international coach body shell structure; new concepts and design techniques versus material standards; structures of BR diesel electric freight locomotives; structural design philosophy for electric locomotives; suspension design for a locomotive with low structural frequencies; freight wagon structures; a finite element study of coal bodyside panels including the effects of joint flexibility; a fresh approach to the problem of car body design strength; energy absorption in automatic couplings and draw gear; passenger vehicle design loads and structural crashworthiness; design of the front part of railway vehicles (in case of frontal impact); the development of a theoretical technique for rail vehicle structural crashworthiness.« less

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 design optimization tasks in the integrated aerospace structural design process. These expert systems were developed to work in conjunction with procedural finite element structural analysis and design optimization modules (developed in-house at SAT, Inc.). The complete software, AutoDesign, so developed, can be used for integrated 'intelligent' structural analysis and design optimization. The software was beta-tested at a variety of companies, used by a range of engineers with different levels of background and expertise. Based on the feedback obtained by such users, conclusions were developed and are provided.

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 design optimization tasks in the integrated aerospace structural design process. These expert systems were developed to work in conjunction with procedural finite element structural analysis and design optimization modules (developed in-house at SAT, Inc.). The complete software, AutoDesign, so developed, can be used for integrated 'intelligent' structural analysis and design optimization. The software was beta-tested at a variety of companies, used by a range of engineers with different levels of background and expertise. Based on the feedback obtained by such users, conclusions were developed and are provided.

Design and Experimental Verification of Deployable/Inflatable Ultra-Lightweight Structures

NASA Technical Reports Server (NTRS)

Pai, P. Frank

2004-01-01

Because launch cost of a space structural system is often proportional to the launch volume and mass and there is no significant gravity in space, NASA's space exploration programs and various science missions have stimulated extensive use of ultra-lightweight deployable/inflatable structures. These structures are named here as Highly Flexible Structures (HFSs) because they are designed to undergo large displacements, rotations, and/or buckling without plastic deformation under normal operation conditions. Except recent applications to space structural systems, HFSs have been used in many mechanical systems, civil structures, aerospace vehicles, home appliances, and medical devices to satisfy space limitations, provide special mechanisms, and/or reduce structural weight. The extensive use of HFSs in today's structural engineering reveals the need of a design and analysis software and a database system with design guidelines for practicing engineers to perform computer-aided design and rapid prototyping of HFSs. Also to prepare engineering students for future structural engineering requires a new and easy-to- understand method of presenting the complex mathematics of the modeling and analysis of HFSs. However, because of the high flexibility of HFSs, many unique challenging problems in the modeling, design and analysis of HFSs need to be studied. The current state of research on HFSs needs advances in the following areas: (1) modeling of large rotations using appropriate strain measures, (2) modeling of cross-section warpings of structures, (3) how to account for both large rotations and cross- section warpings in 2D (two-dimensional) and 1D structural theories, (4) modeling of thickness thinning of membranes due to inflation pressure, pretension, and temperature change, (5) prediction of inflated shapes and wrinkles of inflatable structures, (6) development of efficient numerical methods for nonlinear static and dynamic analyses, and (7) filling the gap between geometrically exact elastic analysis and elastoplastic analysis. The objectives of this research project were: (1) to study the modeling, design, and analysis of deployable/inflatable ultra-lightweight structures, (2) to perform numerical and experimental studies on the static and dynamic characteristics and deployability of HFSs, (3) to derive guidelines for designing HFSs, (4) to develop a MATLAB toolbox for the design, analysis, and dynamic animation of HFSs, and (5) to perform experiments and establish an adequate database of post-buckling characteristics of HFSs.

Ground test facility for SEI nuclear rocket engines

NASA Astrophysics Data System (ADS)

Harmon, Charles D.; Ottinger, Cathy A.; Sanchez, Lawrence C.; Shipers, Larry R.

1992-07-01

Nuclear (fission) thermal propulsion has been identified as a critical technology for a manned mission to Mars by the year 2019. Facilities are required that will support ground tests to qualify the nuclear rocket engine design, which must support a realistic thermal and neutronic environment in which the fuel elements will operate at a fraction of the power for a flight weight reactor/engine. This paper describes the design of a fuel element ground test facility, with a strong emphasis on safety and economy. The details of major structures and support systems of the facility are discussed, and a design diagram of the test facility structures is presented.

Unsteady Probabilistic Analysis of a Gas Turbine System

NASA Technical Reports Server (NTRS)

Brown, Marilyn

2003-01-01

In this work, we have considered an annular cascade configuration subjected to unsteady inflow conditions. The unsteady response calculation has been implemented into the time marching CFD code, MSUTURBO. The computed steady state results for the pressure distribution demonstrated good agreement with experimental data. We have computed results for the amplitudes of the unsteady pressure over the blade surfaces. With the increase in gas turbine engine structural complexity and performance over the past 50 years, structural engineers have created an array of safety nets to ensure against component failures in turbine engines. In order to reduce what is now considered to be excessive conservatism and yet maintain the same adequate margins of safety, there is a pressing need to explore methods of incorporating probabilistic design procedures into engine development. Probabilistic methods combine and prioritize the statistical distributions of each design variable, generate an interactive distribution and offer the designer a quantified relationship between robustness, endurance and performance. The designer can therefore iterate between weight reduction, life increase, engine size reduction, speed increase etc.

Integration of PGD-virtual charts into an engineering design process

NASA Astrophysics Data System (ADS)

Courard, Amaury; Néron, David; Ladevèze, Pierre; Ballere, Ludovic

2016-04-01

This article deals with the efficient construction of approximations of fields and quantities of interest used in geometric optimisation of complex shapes that can be encountered in engineering structures. The strategy, which is developed herein, is based on the construction of virtual charts that allow, once computed offline, to optimise the structure for a negligible online CPU cost. These virtual charts can be used as a powerful numerical decision support tool during the design of industrial structures. They are built using the proper generalized decomposition (PGD) that offers a very convenient framework to solve parametrised problems. In this paper, particular attention has been paid to the integration of the procedure into a genuine engineering design process. In particular, a dedicated methodology is proposed to interface the PGD approach with commercial software.

Synthesis and characterization of transition metal oxide/sulfide nanostructures for electrochemical applications

NASA Astrophysics Data System (ADS)

Yilmaz, Gamze

This thesis is essentially oriented to develop low-cost nanostructured transition metal (nickel and vanadium) oxides and sulfides with high energy density, power density and electrochemical stability via strategies of structural design, hybridization, functionalization and surface engineering. Metal oxide and metal oxide/sulfide hybrid nanostructures in several designs, including hierarchical porous nanostructures, hollow polyhedrons, nanocubes, nanoframes, octopod nanoframes, and nanocages, were synthesized to study the contribution of structural design, compositional engineering, functionalization and surface engineering to the electrochemical properties of the materials. Modulated compositional and structural features disclosed the opportunities of large accessible active sites, facile ion transport, robustness and enhanced electrical conductivity. The best electrochemical performance with merits of highest energy density (38.9 Wh kg-1), power density (7.4 kW kg-1) and electrochemical stability (90.9% after 10000 cycles) was obtained for nickel cobalt layered double hydroxide/cobalt sulfide (NiCo-LDH/Co9S8) hybrid hollow polyhedron structure.

The impact of distributed computing on education

NASA Technical Reports Server (NTRS)

Utku, S.; Lestingi, J.; Salama, M.

1982-01-01

In this paper, developments in digital computer technology since the early Fifties are reviewed briefly, and the parallelism which exists between these developments and developments in analysis and design procedures of structural engineering is identified. The recent trends in digital computer technology are examined in order to establish the fact that distributed processing is now an accepted philosophy for further developments. The impact of this on the analysis and design practices of structural engineering is assessed by first examining these practices from a data processing standpoint to identify the key operations and data bases, and then fitting them to the characteristics of distributed processing. The merits and drawbacks of the present philosophy in educating structural engineers are discussed and projections are made for the industry-academia relations in the distributed processing environment of structural analysis and design. An ongoing experiment of distributed computing in a university environment is described.

Conceptual Design and Structural Analysis of an Open Rotor Hybrid Wing Body Aircraft

NASA Technical Reports Server (NTRS)

Gern, Frank H.

2013-01-01

Through a recent NASA contract, Boeing Research and Technology in Huntington Beach, CA developed and optimized a conceptual design of an open rotor hybrid wing body aircraft (HWB). Open rotor engines offer a significant potential for fuel burn savings over turbofan engines, while the HWB configuration potentially allows to offset noise penalties through possible engine shielding. Researchers at NASA Langley converted the Boeing design to a FLOPS model which will be used to develop take-off and landing trajectories for community noise analyses. The FLOPS model was calibrated using Boeing data and shows good agreement with the original Boeing design. To complement Boeing s detailed aerodynamics and propulsion airframe integration work, a newly developed and validated conceptual structural analysis and optimization tool was used for a conceptual loads analysis and structural weights estimate. Structural optimization and weight calculation are based on a Nastran finite element model of the primary HWB structure, featuring centerbody, mid section, outboard wing, and aft body. Results for flight loads, deformations, wing weight, and centerbody weight are presented and compared to Boeing and FLOPS analyses.

Rocket Engine Oscillation Diagnostics

NASA Technical Reports Server (NTRS)

Nesman, Tom; Turner, James E. (Technical Monitor)

2002-01-01

Rocket engine oscillating data can reveal many physical phenomena ranging from unsteady flow and acoustics to rotordynamics and structural dynamics. Because of this, engine diagnostics based on oscillation data should employ both signal analysis and physical modeling. This paper describes an approach to rocket engine oscillation diagnostics, types of problems encountered, and example problems solved. Determination of design guidelines and environments (or loads) from oscillating phenomena is required during initial stages of rocket engine design, while the additional tasks of health monitoring, incipient failure detection, and anomaly diagnostics occur during engine development and operation. Oscillations in rocket engines are typically related to flow driven acoustics, flow excited structures, or rotational forces. Additional sources of oscillatory energy are combustion and cavitation. Included in the example problems is a sampling of signal analysis tools employed in diagnostics. The rocket engine hardware includes combustion devices, valves, turbopumps, and ducts. Simple models of an oscillating fluid system or structure can be constructed to estimate pertinent dynamic parameters governing the unsteady behavior of engine systems or components. In the example problems it is shown that simple physical modeling when combined with signal analysis can be successfully employed to diagnose complex rocket engine oscillatory phenomena.

A General-Purpose Optimization Engine for Multi-Disciplinary Design Applications

NASA Technical Reports Server (NTRS)

Patnaik, Surya N.; Hopkins, Dale A.; Berke, Laszlo

1996-01-01

A general purpose optimization tool for multidisciplinary applications, which in the literature is known as COMETBOARDS, is being developed at NASA Lewis Research Center. The modular organization of COMETBOARDS includes several analyzers and state-of-the-art optimization algorithms along with their cascading strategy. The code structure allows quick integration of new analyzers and optimizers. The COMETBOARDS code reads input information from a number of data files, formulates a design as a set of multidisciplinary nonlinear programming problems, and then solves the resulting problems. COMETBOARDS can be used to solve a large problem which can be defined through multiple disciplines, each of which can be further broken down into several subproblems. Alternatively, a small portion of a large problem can be optimized in an effort to improve an existing system. Some of the other unique features of COMETBOARDS include design variable formulation, constraint formulation, subproblem coupling strategy, global scaling technique, analysis approximation, use of either sequential or parallel computational modes, and so forth. The special features and unique strengths of COMETBOARDS assist convergence and reduce the amount of CPU time used to solve the difficult optimization problems of aerospace industries. COMETBOARDS has been successfully used to solve a number of problems, including structural design of space station components, design of nozzle components of an air-breathing engine, configuration design of subsonic and supersonic aircraft, mixed flow turbofan engines, wave rotor topped engines, and so forth. This paper introduces the COMETBOARDS design tool and its versatility, which is illustrated by citing examples from structures, aircraft design, and air-breathing propulsion engine design.

14 CFR 27.549 - Fuselage, landing gear, and rotor pylon structures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (Secs. 604, 605, 72 Stat. 778, 49 U.S.C...

14 CFR 27.549 - Fuselage, landing gear, and rotor pylon structures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (Secs. 604, 605, 72 Stat. 778, 49 U.S.C...

A Real-Time All-Atom Structural Search Engine for Proteins

PubMed Central

Gonzalez, Gabriel; Hannigan, Brett; DeGrado, William F.

2014-01-01

Protein designers use a wide variety of software tools for de novo design, yet their repertoire still lacks a fast and interactive all-atom search engine. To solve this, we have built the Suns program: a real-time, atomic search engine integrated into the PyMOL molecular visualization system. Users build atomic-level structural search queries within PyMOL and receive a stream of search results aligned to their query within a few seconds. This instant feedback cycle enables a new “designability”-inspired approach to protein design where the designer searches for and interactively incorporates native-like fragments from proven protein structures. We demonstrate the use of Suns to interactively build protein motifs, tertiary interactions, and to identify scaffolds compatible with hot-spot residues. The official web site and installer are located at http://www.degradolab.org/suns/ and the source code is hosted at https://github.com/godotgildor/Suns (PyMOL plugin, BSD license), https://github.com/Gabriel439/suns-cmd (command line client, BSD license), and https://github.com/Gabriel439/suns-search (search engine server, GPLv2 license). PMID:25079944

Application of fiber-reinforced bismaleimide materials to aircraft nacelle structures

NASA Technical Reports Server (NTRS)

Peros, Vasilios; Ruth, John; Trawinski, David

1992-01-01

Existing aircraft engine nacelle structures employ advanced composite materials to reduce weight and thereby increase overall performance. Use of advanced composite materials on existing aircraft nacelle structures includes fiber-reinforced epoxy structures and has typically been limited to regions furthest away from the hot engine core. Portions of the nacelle structure that are closer to the engine require materials with a higher temperature capability. In these portions, existing nacelle structures employ aluminum sandwich construction and skin/stringer construction. The aluminum structure is composed of many detail parts and assemblies and is usually protected by some form of ablative, insulator, or metallic thermal shield. A one-piece composite inner cowl for a new-generation engine nacelle structure has been designed using fiber-reinforced bismaleimide (BMI) materials and honeycomb core in a sandwich construction. The new composite design has many advantages over the existing aluminum structure. Multiple details were integrated into the one-piece composite design, thereby significantly reducing the number of detail parts and fasteners. The use of lightweight materials and the reduction of the number of joints result in a significant weight reduction over the aluminum design; manufacturing labor and the overall number of tools required have also been reduced. Several significant technical issues were addressed in the development of a BMI composite design. Technical evaluation of the available BMI systems led to the selection of a toughened BMI material which was resistant to microcracking under thermal cyclic loading and enhanced the damage tolerance of the structure. Technical evaluation of the degradation of BMI materials in contact with aluminum and other metals validated methods for isolation of the various materials. Graphite-reinforced BMI in contact with aluminum and some steels was found to degrade in salt spray testing. Isolation techniques such as those used for graphite-reinforced epoxy structures were shown to provide adequate protection. The springback and producibility of large BMI structures were evaluated by manufacturing prototype hardware which had the full-scale cross section of the one-piece composite structure.

Feasibility of magnetic bearings for advanced gas turbine engines

NASA Technical Reports Server (NTRS)

Hibner, David; Rosado, Lewis

1992-01-01

The application of active magnetic bearings to advanced gas turbine engines will provide a product with major improvements compared to current oil lubricated bearing designs. A rethinking of the engine rotating and static structure design is necessary and will provide the designer with significantly more freedom to meet the demanding goals of improved performance, increased durability, higher reliability, and increased thrust to weight ratio via engine weight reduction. The product specific technology necessary for this high speed, high temperature, dynamically complex application has been defined. The resulting benefits from this approach to aircraft engine rotor support and the complementary engine changes and improvements have been assessed.

Engineering and Design: Composite Materials for Civil Engineering Structures

DTIC Science & Technology

1997-03-31

the effects of acidic, salt, and fresh waters . Acidic, salt, and fresh waters are corrosive to ferrous metals. In Corps of Engineers structures, high...what is commonly called a toughened epoxy. (5) Polymeric resins will absorb moisture. Since many applications are in contact with water (at least...ultraviolet radiation. Some coatings can reduce the amount of moisture absorption by the structure. All polymeric resins will absorb water to some

Assessing Students' Structured Programming Skills with Java: The "Blue, Berry, and Blueberry" Assignment

ERIC Educational Resources Information Center

Zhang, Xihui

2010-01-01

Java is an object-oriented programming language. From a software engineering perspective, object-oriented design and programming is used at the architectural design, and structured design and programming is used at the detailed design within methods. As such, structured programming skills are fundamental to more advanced object-oriented…

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1991-01-01

ATTAP activities were highlighted by test bed engine design and development activities; ceramic component design; materials and engine component characterization; ceramic component process development and fabrication; component rig testing; and test bed engine fabrication and testing. Specifically, ATTAP aims to develop and demonstrate the technology of structural ceramics that have the potential for competitive automotive engine life cycle cost and for operating for 3500 hours in a turbine engine environment at temperatures up to 1371 C (2500 F).

A Study of Vehicle Structural Layouts in Post-WWII Aircraft

NASA Technical Reports Server (NTRS)

Sensmeier, Mark D.; Samareh, Jamshid A.

2004-01-01

In this paper, results of a study of structural layouts of post-WWII aircraft are presented. This study was undertaken to provide the background information necessary to determine typical layouts, design practices, and industry trends in aircraft structural design. Design decisions are often predicated not on performance-related criteria, but rather on such factors as manufacturability, maintenance access, and of course cost. For this reason, a thorough understanding of current best practices in the industry is required as an input for the design optimization process. To determine these best practices and industry trends, a large number of aircraft structural cutaway illustrations were analyzed for five different aircraft categories (commercial transport jets, business jets, combat jet aircraft, single engine propeller aircraft, and twin-engine propeller aircraft). Several aspects of wing design and fuselage design characteristics are presented here for the commercial transport and combat aircraft categories. A great deal of commonality was observed for transport structure designs over a range of eras and manufacturers. A much higher degree of variability in structural designs was observed for the combat aircraft, though some discernable trends were observed as well.

Effects of Interdisciplinary Education on Technology-Driven Application Design

ERIC Educational Resources Information Center

Tafa, Z.; Rakocevic, G.; Mihailovic, D.; Milutinovic, V.

2011-01-01

This paper describes the structure and the underlying rationale of a new course dedicated to capability maturity model integration (CMMI)-directed design of wireless sensor networks (WSNs)-based biomedical applications that stresses: 1) engineering-, medico-engineering-, and informatics-related issues; 2) design for general- and special-purpose…

A review of rapid prototyping techniques for tissue engineering purposes.

PubMed

Peltola, Sanna M; Melchels, Ferry P W; Grijpma, Dirk W; Kellomäki, Minna

2008-01-01

Rapid prototyping (RP) is a common name for several techniques, which read in data from computer-aided design (CAD) drawings and manufacture automatically three-dimensional objects layer-by-layer according to the virtual design. The utilization of RP in tissue engineering enables the production of three-dimensional scaffolds with complex geometries and very fine structures. Adding micro- and nanometer details into the scaffolds improves the mechanical properties of the scaffold and ensures better cell adhesion to the scaffold surface. Thus, tissue engineering constructs can be customized according to the data acquired from the medical scans to match the each patient's individual needs. In addition RP enables the control of the scaffold porosity making it possible to fabricate applications with desired structural integrity. Unfortunately, every RP process has its own unique disadvantages in building tissue engineering scaffolds. Hence, the future research should be focused on the development of RP machines designed specifically for fabrication of tissue engineering scaffolds, although RP methods already can serve as a link between tissue and engineering.

Automotive Design

NASA Technical Reports Server (NTRS)

1991-01-01

Analytical Design Service Corporation, Ann Arbor, MI, used NASTRAN (a NASA Structural Analysis program that analyzes a design and predicts how parts will perform) in tests of transmissions, engine cooling systems, internal engine parts, and body components. They also use it to design future automobiles. Analytical software can save millions by allowing computer simulated analysis of performance even before prototypes are built.

New Tools Being Developed for Engine- Airframe Blade-Out Structural Simulations

NASA Technical Reports Server (NTRS)

Lawrence, Charles

2003-01-01

One of the primary concerns of aircraft structure designers is the accurate simulation of the blade-out event. This is required for the aircraft to pass Federal Aviation Administration (FAA) certification and to ensure that the aircraft is safe for operation. Typically, the most severe blade-out occurs when a first-stage fan blade in a high-bypass gas turbine engine is released. Structural loading results from both the impact of the blade onto the containment ring and the subsequent instantaneous unbalance of the rotating components. Reliable simulations of blade-out are required to ensure structural integrity during flight as well as to guarantee successful blade-out certification testing. The loads generated by these analyses are critical to the design teams for several components of the airplane structures including the engine, nacelle, strut, and wing, as well as the aircraft fuselage. Currently, a collection of simulation tools is used for aircraft structural design. Detailed high-fidelity simulation tools are used to capture the structural loads resulting from blade loss, and then these loads are used as input into an overall system model that includes complete structural models of both the engines and the airframe. The detailed simulation (shown in the figure) includes the time-dependent trajectory of the lost blade and its interactions with the containment structure, and the system simulation includes the lost blade loadings and the interactions between the rotating turbomachinery and the remaining aircraft structural components. General-purpose finite element structural analysis codes are typically used, and special provisions are made to include transient effects from the blade loss and rotational effects resulting from the engine s turbomachinery. To develop and validate these new tools with test data, the NASA Glenn Research Center has teamed with GE Aircraft Engines, Pratt & Whitney, Boeing Commercial Aircraft, Rolls-Royce, and MSC.Software.

A Software Tool for Integrated Optical Design Analysis

NASA Technical Reports Server (NTRS)

Moore, Jim; Troy, Ed; DePlachett, Charles; Montgomery, Edward (Technical Monitor)

2001-01-01

Design of large precision optical systems requires multi-disciplinary analysis, modeling, and design. Thermal, structural and optical characteristics of the hardware must be accurately understood in order to design a system capable of accomplishing the performance requirements. The interactions between each of the disciplines become stronger as systems are designed lighter weight for space applications. This coupling dictates a concurrent engineering design approach. In the past, integrated modeling tools have been developed that attempt to integrate all of the complex analysis within the framework of a single model. This often results in modeling simplifications and it requires engineering specialist to learn new applications. The software described in this presentation addresses the concurrent engineering task using a different approach. The software tool, Integrated Optical Design Analysis (IODA), uses data fusion technology to enable a cross discipline team of engineering experts to concurrently design an optical system using their standard validated engineering design tools.

Crashworthy airframe design concepts: Fabrication and testing

NASA Technical Reports Server (NTRS)

Cronkhite, J. D.; Berry, V. L.

1982-01-01

Crashworthy floor concepts applicable to general aviation aircraft metal airframe structures were investigated. Initially several energy absorbing lower fuselage structure concepts were evaluated. Full scale floor sections representative of a twin engine, general aviation airplane lower fuselage structure were designed and fabricated. The floors featured an upper high strength platform with an energy absorbing, crushable structure underneath. Eighteen floors were fabricated that incorporated five different crushable subfloor concepts. The floors were then evaluated through static and dynamic testing. Computer programs NASTRAN and KRASH were used for the static and dynamic analysis of the floor section designs. Two twin engine airplane fuselages were modified to incorporate the most promising crashworthy floor sections for test evaluation.

Draftsmen at Work during Construction of the Aircraft Engine Research Laboratory

NASA Image and Video Library

1942-09-21

The National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory was designed by a group of engineers at the Langley Memorial Aeronautical Laboratory in late 1940 and 1941. Under the guidance of Ernest Whitney, the men worked on drawings and calculations in a room above Langley’s Structural Research Laboratory. The main Aircraft Engine Research Laboratory design group originally consisted of approximately 30 engineers and draftsmen, but there were smaller groups working separately on specific facilities. The new engine lab would have six principal buildings: the Engine Research Building, hangar, Fuels and Lubricants Building, Administration Building, Propeller Test Stand, and Altitude Wind Tunnel. In December 1941 most of those working on the project transferred to Cleveland from Langley. Harrison Underwood and Charles Egan led 18 architectural, 26 machine equipment, 3 structural and 10 mechanical draftsmen. Initially these staff members were housed in temporary offices in the hangar. As sections of the four-acre Engine Research Building were completed in the summer of 1942, the design team began relocating there. The Engine Research Building contained a variety of test cells and laboratories to address virtually every aspect of piston engine research. It also contained a two-story office wing, seen in this photograph that would later house many of the powerplant research engineers.

Lessons learned for composite structures

NASA Technical Reports Server (NTRS)

Whitehead, R. S.

1991-01-01

Lessons learned for composite structures are presented in three technology areas: materials, manufacturing, and design. In addition, future challenges for composite structures are presented. Composite materials have long gestation periods from the developmental stage to fully matured production status. Many examples exist of unsuccessful attempts to accelerate this gestation period. Experience has shown that technology transition of a new material system to fully matured production status is time consuming, involves risk, is expensive and should not be undertaken lightly. The future challenges for composite materials require an intensification of the science based approach to material development, extension of the vendor/customer interaction process to include all engineering disciplines of the end user, reduced material costs because they are a significant factor in overall part cost, and improved batch-to-batch pre-preg physical property control. Historical manufacturing lessons learned are presented using current in-service production structure as examples. Most producibility problems for these structures can be traced to their sequential engineering design. This caused an excessive emphasis on design-to-weight and schedule at the expense of design-to-cost. This resulted in expensive performance originated designs, which required costly tooling and led to non-producible parts. Historically these problems have been allowed to persist throughout the production run. The current/future approach for the production of affordable composite structures mandates concurrent engineering design where equal emphasis is placed on product and process design. Design for simplified assembly is also emphasized, since assembly costs account for a major portion of total airframe costs. The future challenge for composite manufacturing is, therefore, to utilize concurrent engineering in conjunction with automated manufacturing techniques to build affordable composite structures. Composite design experience has shown that significant weight savings have been achieved, outstanding fatigue and corrosion resistance have been demonstrated, and in-service performance has been very successful. Currently no structural design show stoppers exist for composite structures. A major lesson learned is that the full scale static test is the key test for composites, since it is the primary structural 'hot spot' indicator. The major durability issue is supportability of thin skinned structure. Impact damage has been identified as the most significant issue for the damage tolerance control of composite structures. However, delaminations induced during assembly operations have demonstrated a significant nuisance value. The future challenges for composite structures are threefold. Firstly, composite airframe weight fraction should increase to 60 percent. At the same time, the cost of composite structures must be reduced by 50 percent to attain the goal of affordability. To support these challenges it is essential to develop lower cost materials and processes.

DEVELOPMENT OF A SUPERSONIC TRANSPORT AIRCRAFT ENGINE - PHASE II-A.

DTIC Science & Technology

JET TRANSPORT PLANES, *SUPERSONIC AIRCRAFT ) (U) TURBOJET ENGINES , PERFORMANCE( ENGINEERING ), TURBOFAN ENGINES , AFTERBURNING, SPECIFICATIONS...COMPRESSORS, GEOMETRY, TURBOJET INLETS, COMBUSTION, TEST EQUIPMENT, TURBINE BLADES , HEAT TRANSFER, AIRFOILS , CASCADE STRUCTURES, EVAPOTRANSPIRATION, PLUG NOZZLES, ANECHOIC CHAMBERS, BEARINGS, SEALS, DESIGN, FATIGUE(MECHANICS)

Facet‐Engineered Surface and Interface Design of Photocatalytic Materials

PubMed Central

Wang, Lili; Li, Zhengquan

2016-01-01

The facet‐engineered surface and interface design for photocatalytic materials has been proven as a versatile approach to enhance their photocatalytic performance. This review article encompasses some recent advances in the facet engineering that has been performed to control the surface of mono‐component semiconductor systems and to design the surface and interface structures of multi‐component heterostructures toward photocatalytic applications. The review begins with some key points which should receive attention in the facet engineering on photocatalytic materials. We then discuss the synthetic approaches to achieve the facet control associated with the surface and interface design. In the following section, the facet‐engineered surface design on mono‐component photocatalytic materials is introduced, which forms a basis for the discussion on more complex systems. Subsequently, we elucidate the facet‐engineered surface and interface design of multi‐component photocatalytic materials. Finally, the existing challenges and future prospects are discussed. PMID:28105398

Liquid rocket engine centrifugal flow turbopumps. [design criteria

NASA Technical Reports Server (NTRS)

1973-01-01

Design criteria and recommended practices are discussed for the following configurations selected from the design sequence of a liquid rocket engine centrifugal flow turbopump: (1) pump performance including speed, efficiency, and flow range; (2) impeller; (3) housing; and (4) thrust balance system. Hydrodynamic, structural, and mechanical problems are addressed for the achievement of required pump performance within the constraints imposed by the engine/turbopump system. Materials and fabrication specifications are also discussed.

Collaboration between Industrial Designers and Design Engineers - Comparing the Understanding of Design Intent.

PubMed

Laursen, Esben Skov; Møller, Louise

2015-01-01

This paper describes a case study comparing the understanding of design intent between industrial designers and design engineers. The study is based on the hypothesis that it is not all aspects of the design intent that are equally difficult to share between industrial designers and design engineers in the product development process. The study builds on five semi-structured interviews, where two industrial designers and three design engineers were interviewed about different aspects of the design intent. Based on our results, there seem to be indications that the more complex and abstract elements of industrial design knowledge such as the meaning, semantics, values, emotions and social aspects of the product are less shared by the design engineers. Moreover, the results also indicate that the different aspects of the design intent are perceived separately, rather than as part of a whole by the design engineers. The connection between the different aspects of the design intent is not shared between the industrial designer and design engineer making the shared knowledge less meaningful to the design engineers. The results of this study cannot be claimed to be conclusive due to the limited empirical material. Further investigation and analytically richer data are required in order to verify and broaden the findings. More case studies have therefore been planned in order to understand the area better.

Multidisciplinary design integration system for a supersonic transport aircraft

NASA Technical Reports Server (NTRS)

Dovi, A. R.; Wrenn, G. A.; Barthelemy, J.-F. M.; Coen, P. G.; Hall, L. E.

1992-01-01

An aircraft preliminary design system which provides the multidisciplinary communications and couplings between several engineering disciplines is described. A primary benefit of this system is to demonstrate advanced technology multidisciplinary design integration methodologies. The current version includes the disciplines of aerodynamics and structures. Contributing engineering disciplines are coupled using the Global Sensitivity Equation approach to influence the global design optimization problem. A high speed civil transport configuration is used for configuration trade studies. Forty four independent design variables are used to control the cross-sectional areas of wing rib and spar caps and the thicknesses of wingskincover panels. A total of 300 stress, strain, buckling and displacement behavioral constraints and minimum gages on the design variables were used to optimize the idealized wing structure. The goal of the designs to resize the wing cover panels and internal structure for minimum mass.

14 CFR 23.361 - Engine torque.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... rational analysis, a factor of 1.6 must be used. (b) For turbine engine installations, the engine mounts... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Engine torque. 23.361 Section 23.361...

14 CFR 23.361 - Engine torque.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... rational analysis, a factor of 1.6 must be used. (b) For turbine engine installations, the engine mounts... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Engine torque. 23.361 Section 23.361...

14 CFR 23.361 - Engine torque.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... rational analysis, a factor of 1.6 must be used. (b) For turbine engine installations, the engine mounts... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Engine torque. 23.361 Section 23.361...

14 CFR 23.361 - Engine torque.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... rational analysis, a factor of 1.6 must be used. (b) For turbine engine installations, the engine mounts... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Engine torque. 23.361 Section 23.361...

14 CFR 23.361 - Engine torque.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Engine torque. (a) Each engine mount and its supporting structure must be designed for the effects of— (1... rational analysis, a factor of 1.6 must be used. (b) For turbine engine installations, the engine mounts... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Engine torque. 23.361 Section 23.361...

Analysis of liquid-propellant rocket engines designed by F. A. Tsander

NASA Technical Reports Server (NTRS)

Dushkin, L. S.; Moshkin, Y. K.

1977-01-01

The development of the oxygen-gasoline OR-2 engines and the oxygen-alcohol GIRD-10 rocket engine is described. A result of Tsander's rocket research was an engineering method for propellant calculation of oxygen-propellant rocket engines that determined the basic parameters of the engine and the structural elements.

Computer-Aided Design Of Turbine Blades And Vanes

NASA Technical Reports Server (NTRS)

Hsu, Wayne Q.

1988-01-01

Quasi-three-dimensional method for determining aerothermodynamic configuration of turbine uses computer-interactive analysis and design and computer-interactive graphics. Design procedure executed rapidly so designer easily repeats it to arrive at best performance, size, structural integrity, and engine life. Sequence of events in aerothermodynamic analysis and design starts with engine-balance equations and ends with boundary-layer analysis and viscous-flow calculations. Analysis-and-design procedure interactive and iterative throughout.

Structural dynamic analysis of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Scott, L. P.; Jamison, G. T.; Mccutcheon, W. A.; Price, J. M.

1981-01-01

This structural dynamic analysis supports development of the SSME by evaluating components subjected to critical dynamic loads, identifying significant parameters, and evaluating solution methods. Engine operating parameters at both rated and full power levels are considered. Detailed structural dynamic analyses of operationally critical and life limited components support the assessment of engine design modifications and environmental changes. Engine system test results are utilized to verify analytic model simulations. The SSME main chamber injector assembly is an assembly of 600 injector elements which are called LOX posts. The overall LOX post analysis procedure is shown.

Advanced materials for aircraft engine applications.

PubMed

Backman, D G; Williams, J C

1992-02-28

A review of advances for aircraft engine structural materials and processes is presented. Improved materials, such as superalloys, and the processes for making turbine disks and blades have had a major impact on the capability of modern gas turbine engines. New structural materials, notably composites and intermetallic materials, are emerging that will eventually further enhance engine performance, reduce engine weight, and thereby enable new aircraft systems. In the future, successful aerospace manufacturers will combine product design and materials excellence with improved manufacturing methods to increase production efficiency, enhance product quality, and decrease the engine development cycle time.

Airborne remote sensors applied to engineering geology and civil works design investigations

NASA Technical Reports Server (NTRS)

Gelnett, R. H.

1975-01-01

The usefulness of various airborne remote sensing systems in the detection and identification of regional and specific geologic structural features that may affect the design and location of engineering structures on major civil works projects is evaluated. The Butler Valley Dam and Blue Lake Project in northern California was selected as a demonstration site. Findings derived from the interpretation of various kinds of imagery used are given.

Phase-Change Memory Materials by Design: A Strain Engineering Approach.

PubMed

Zhou, Xilin; Kalikka, Janne; Ji, Xinglong; Wu, Liangcai; Song, Zhitang; Simpson, Robert E

2016-04-20

Van der Waals heterostructure superlattices of Sb2 Te1 and GeTe are strain-engineered to promote switchable atomic disordering, which is confined to the GeTe layer. Careful control of the strain in the structures presents a new degree of freedom to design the properties of functional superlattice structures for data storage and photonics applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Strategic Design and Fabrication of Engineered Scaffolds for Articular Cartilage Repair

PubMed Central

Izadifar, Zohreh; Chen, Xiongbiao; Kulyk, William

2012-01-01

Damage to articular cartilage can eventually lead to osteoarthritis (OA), a debilitating, degenerative joint disease that affects millions of people around the world. The limited natural healing ability of cartilage and the limitations of currently available therapies make treatment of cartilage defects a challenging clinical issue. Hopes have been raised for the repair of articular cartilage with the help of supportive structures, called scaffolds, created through tissue engineering (TE). Over the past two decades, different designs and fabrication techniques have been investigated for developing TE scaffolds suitable for the construction of transplantable artificial cartilage tissue substitutes. Advances in fabrication technologies now enable the strategic design of scaffolds with complex, biomimetic structures and properties. In particular, scaffolds with hybrid and/or biomimetic zonal designs have recently been developed for cartilage tissue engineering applications. This paper reviews critical aspects of the design of engineered scaffolds for articular cartilage repair as well as the available advanced fabrication techniques. In addition, recent studies on the design of hybrid and zonal scaffolds for use in cartilage tissue repair are highlighted. PMID:24955748

Design and implementation of workflow engine for service-oriented architecture

NASA Astrophysics Data System (ADS)

Peng, Shuqing; Duan, Huining; Chen, Deyun

2009-04-01

As computer network is developed rapidly and in the situation of the appearance of distribution specialty in enterprise application, traditional workflow engine have some deficiencies, such as complex structure, bad stability, poor portability, little reusability and difficult maintenance. In this paper, in order to improve the stability, scalability and flexibility of workflow management system, a four-layer architecture structure of workflow engine based on SOA is put forward according to the XPDL standard of Workflow Management Coalition, the route control mechanism in control model is accomplished and the scheduling strategy of cyclic routing and acyclic routing is designed, and the workflow engine which adopts the technology such as XML, JSP, EJB and so on is implemented.

Quiet Clean Short-Haul Experimental Engine (QCSEE) Under-the-Wing (UTW) Final Design Report

NASA Technical Reports Server (NTRS)

1977-01-01

The QCSEE Program provides for the design, fabrication, and testing of two experimental high-bypass geared turbofan engines and propulsion systems for short-haul passenger aircraft. The overall objective of the program is to develop the propulsion technology required for future externally blown flap types of aircraft with engines located both under-the-wing and over-the-wing. This technology includes work in composite structures and digital engine controls.

Evidence-Based Conclusions Concerning Practice, Curriculum Design and Curriculum Reform in a Civil Engineering Capstone Design Course in Hong Kong

ERIC Educational Resources Information Center

Chan, Cecilia K. Y.; Wong, George C. K.; Law, Ada K. H.; Zhang, T.; Au, Francis T. K.

2017-01-01

This study aimed to provide evidence-based conclusions from students concerning a capstone-design course in a civil engineering programme in Hong Kong. The evidence was generated by designing a student-experience questionnaire. The questionnaire instrument was assessed for internal consistency in four scales (curriculum and structure changes;…

14 CFR 33.70 - Engine life-limited parts.

Code of Federal Regulations, 2014 CFR

2014-01-01

... parts are rotor and major static structural parts whose primary failure is likely to result in a....70 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.70 Engine life...

Design the Cost Approach in Trade-Off's for Structural Components, Illustrated on the Baseline Selection of the Engine Thrust Frame of Ariane 5 ESC-B

NASA Astrophysics Data System (ADS)

Appolloni, L.; Juhls, A.; Rieck, U.

2002-01-01

Designing for value is one of the very actual upcoming methods for design optimization, which broke into the domain of aerospace engineering in the late 90's. In the frame of designing for value two main design philosophies exist: Design For Cost and Design To Cost. Design To Cost is the iterative redesign of a project until the content of the project meets a given budget. Designing For Cost is the conscious use of engineering process technology to reduce life cycle cost while satisfying, and hopefully exceeding, customer demands. The key to understanding cost, and hence to reducing cost, is the ability to measure cost accurately and to allocate it appropriately to products. Only then can intelligent decisions be made. Therefore the necessity of new methods as "Design For Value" or "Design For Competitiveness", set up with a generally multidisciplinary approach to find an optimized technical solution driven by many parameters, depending on the mission scenario and the customer/market needs. Very often three, but not more than five parametric drivers are sufficient. The more variable exist, the higher is in fact the risk to find just a sub-optimized local and not the global optimum, and the less robust is the found solution against change of input parameters. When the main parameters for optimization have been identified, the system engineer has to communicate them to all design engineers, who shall take care of these assessment variables during the entire design and decision process. The design process which has taken to the definition of the feasible structural concepts for the Engine Thrust Frame of the Ariane 5 Upper Cryogenic Stage ESC-B follows these most actual design philosophy methodologies, and combines a design for cost approach, to a design to cost optimization loop. Ariane 5 is the first member of a family of heavy-lift launchers. It aims to evolve into a family of launchers that responds to the space transportation challenges of the 21st century. New upper stages, along with modifications to the main cryogenic stage and solid boosters, will increase performance and meet demands of a changing market. A two-steps approach was decided for future developments of the launcher upper stage, in order to increase the payload lift capability of Ariane 5. The first step ESC-A is scheduled for first launch in 2002. As later step ESC-B shall grow up to 12 tons in GTO orbit, with multiple restart capability, i.e. re-ignitable engine. Ariane 5 ESC-B first flight is targeted for 2006. It will be loaded with 28 metric tons of liquid oxygen and liquid hydrogen and powered by a new expander cycle engine "Vinci". The Vinci engine will be connected to the tanks of the ESC-B stage via the structure named from the designers ETF, or Engine Thrust Frame. In order to develop a design concept for the ETF component a trade off was performed, based on the most modern system engineering methodologies. This paper will describe the basis of the system engineering approach in the design to cost process, and illustrate such approach as it has been applied during the trade off for the baseline selection of the Engine Thrust Frame of Ariane 5 ESC-B.

The J-2X Oxidizer Turbopump - Design, Development, and Test

NASA Technical Reports Server (NTRS)

Brozowski, Laura A.; Beatty, D. Preston; Shinguchi, Brian H.; Marsh, Matthew W.

2011-01-01

Pratt and Whitney Rocketdyne (PWR), a NASA subcontractor, is executing the Design, Development, Test, and Evaluation (DDT&E) of a liquid oxygen, liquid hydrogen two hundred ninety-four thousand pound thrust rocket engine initially intended for the Upper Stage (US) and Earth Departure Stage (EDS) of the Constellation Program Ares-I Crew Launch Vehicle (CLV). A key element of the design approach was to base the new J-2X engine on the heritage J-2S engine which was a design upgrade of the flight proven J-2 engine used to put American astronauts on the moon. This paper will discuss the design trades and analyses performed to achieve the required uprated Oxidizer Turbopump performance; structural margins and rotordynamic margins; incorporate updated materials and fabrication capability; and reflect lessons learned from legacy and existing Liquid Rocket Propulsion Engine turbomachinery. These engineering design, analysis, fabrication and assembly activities support the Oxidizer Turbopump readiness for J-2X engine test in 2011.

Austrian Guideline for Geomechanical Design of Tunnels - Necessity for Cooperation between Geologists, Geotechnical and Civil Engineers

NASA Astrophysics Data System (ADS)

Schwarz, Ludwig; Eder, Stefan; Mattle, Bruno; Hammer, Helmut

Rising competitive pressure in the construction business, ever tighter schedules being set up by the clients and ongoing disputes between engineering geologists and civil engineers about the role of geotechnical engineers have - in the last few years - led to increasing discussions between engineers and geologists about the allocation of competences during the design process of underground structures. In the course of this debate, which is often polemic and anything but objective, important information is quite frequently lost - a development which may not only be to the disadvantage of the client but which may also do damage to the reputation of the professions involved. The design procedure of the new Austrian guideline for the geomechanical design of underground structures requires a close collaboration of geologists, geotechnical and civil engineers, yet without allocating competences. While preparing the tender documents for the first construction lot of the Northern feeder line of the Brenner base tunnel, the necessity of a close cooperation of the involved professions became apparent due to the complex geological situation encountered in the project area and the enormous amount of data available. Despite these difficult boundary conditions, the successful application of the guideline was last but not least the result of the joint efforts of the multidisciplinary design team.

The Application of Concurrent Engineering Tools and Design Structure Matrix in Designing Tire

NASA Astrophysics Data System (ADS)

Ginting, Rosnani; Fachrozi Fitra Ramadhan, T.

2016-02-01

The development of automobile industry in Indonesia is growing rapidly. This phenomenon causes companies related to the automobile industry such as tire industry must develop products based on customers’ needs and considering the timeliness of delivering the product to the customer. It could be reached by applying strategic planning in developing an integrated concept of product development. This research was held in PT. XYZ that applied the sequential approach in designing and developing products. The need to improve in one stage of product development could occur re-designing that needs longer time in developing a new product. This research is intended to get an integrated product design concept of tire pertaining to the customer's needs using Concurrent Engineering Tools by implementing the two-phased of product development. The implementation of Concurrent Engineering approach results in applying the stage of project planning, conceptual design, and product modules. The product modules consist of four modules that using Product Architecture - Design Structure Matrix to ease the designing process of new product development.

The design, fabrication and characterization of fluidic membranes for micro-engines with the aim of frequency lowering

NASA Astrophysics Data System (ADS)

Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

2016-12-01

This paper describes the design, microfabrication and linear dynamic characterization of low frequency thick membranes as a potential technological solution for resonant micro-engines, for which classical pistons cannot be used. The proposed structure is called a hybrid fluid-membrane and consists of two thin flexible membranes that encapsulate an incompressible fluid. Lower frequency structures, compared to geometrically equivalent single layer membranes, are thus obtained. Each flexible membrane is based on a composite structure which comprises a silicon planar logarithmic spiral spring embedded in a room temperature vulcanization silicone polymer. Thus, the stiffness and sealing features are dissociated for a better design control. The developed realization and assembly process is demonstrated at the wafer level. The process involves the anodic bonding of multiple stacks of silicon/glass structures, fluid filling and sealing. Various dimensions of hybrid fluid-membranes are successfully fabricated. Their dynamic characterization underlines the agreement between experimental and theoretical results. The results provide the opportunity for the design and fabrication of low frequency membranes to match the dynamics requirements of micro-engines.

Evaluation of creative problem-solving abilities in undergraduate structural engineers through interdisciplinary problem-based learning

NASA Astrophysics Data System (ADS)

McCrum, Daniel Patrick

2017-11-01

For a structural engineer, effective communication and interaction with architects cannot be underestimated as a key skill to success throughout their professional career. Structural engineers and architects have to share a common language and understanding of each other in order to achieve the most desirable architectural and structural designs. This interaction and engagement develops during their professional career but needs to be nurtured during their undergraduate studies. The objective of this paper is to present the strategies employed to engage higher order thinking in structural engineering students in order to help them solve complex problem-based learning (PBL) design scenarios presented by architecture students. The strategies employed were applied in the experimental setting of an undergraduate module in structural engineering at Queen's University Belfast in the UK. The strategies employed were active learning to engage with content knowledge, the use of physical conceptual structural models to reinforce key concepts and finally, reinforcing the need for hand sketching of ideas to promote higher order problem-solving. The strategies employed were evaluated through student survey, student feedback and module facilitator (this author) reflection. The strategies were qualitatively perceived by the tutor and quantitatively evaluated by students in a cross-sectional study to help interaction with the architecture students, aid interdisciplinary learning and help students creatively solve problems (through higher order thinking). The students clearly enjoyed this module and in particular interacting with structural engineering tutors and students from another discipline.

Quantum Engineering of States in Heterostructure-based Detectors for Enhance Performance

DTIC Science & Technology

2017-05-26

excited carrier contribution in these heterostructure- based photodetectors has been reduced by using phonon-assisted transitions to design structures ...experimental investigations of nanostructure- based electronic and optoelectronic structures with the goal of facilitating major improvements in the performance...nanostructures. Quantum engineering of nano- structures is emphasized. Related quantum- based structures – including those with spontaneous polarizations are

Prototype design and test of a collision protection system for cab car engineers.

DOT National Transportation Integrated Search

2014-12-01

Advancements in the design of rail cars can : potentially prevent the structural collapse of : space occupied by a cab car engineer : during a train collision. With adequate : survival space maintained, the next : crashworthiness objective is to mini...

Quiet Clean Short-haul Experimental Engine (QCSEE) composite fan frame design report

NASA Technical Reports Server (NTRS)

Mitchell, S. C.

1978-01-01

An advanced composite frame which is flight-weight and integrates the functions of several structures was developed for the over the wing (OTW) engine and for the under the wing (UTW) engine. The composite material system selected as the basic material for the frame is Type AS graphite fiber in a Hercules 3501 epoxy resin matrix. The frame was analyzed using a finite element digital computer program. This program was used in an iterative fashion to arrive at practical thicknesses and ply orientations to achieve a final design that met all strength and stiffness requirements for critical conditions. Using this information, the detail design of each of the individual parts of the frame was completed and released. On the basis of these designs, the required tooling was designed to fabricate the various component parts of the frame. To verify the structural integrity of the critical joint areas, a full-scale test was conducted on the frame before engine testing. The testing of the frame established critical spring constants and subjected the frame to three critical load cases. The successful static load test was followed by 153 and 58 hours respectively of successful running on the UTW and OTW engines.

The nature of operating flight loads and their effect on propulsion system structures

NASA Technical Reports Server (NTRS)

Dickenson, K. H.; Martin, R. L.

1981-01-01

Past diagnostics studies revealed the primary causes of performance deterioration of high by-pass turbofan engines to be flight loads, erosion, and thermal distortion. The various types of airplane loads that are imposed on the engine throughout the lifetime of an airplane are examined. These include flight loads from gusts and maneuvers and ground loads from takeoff, landing, and taxi conditions. Clarification is made in definitions of the airframer's limit and ultimate design loads and the engine manufacturer's operating design loads. Finally, the influence of these loads on the propulsion system structures is discussed.

Gene Composer: database software for protein construct design, codon engineering, and gene synthesis

PubMed Central

Lorimer, Don; Raymond, Amy; Walchli, John; Mixon, Mark; Barrow, Adrienne; Wallace, Ellen; Grice, Rena; Burgin, Alex; Stewart, Lance

2009-01-01

Background To improve efficiency in high throughput protein structure determination, we have developed a database software package, Gene Composer, which facilitates the information-rich design of protein constructs and their codon engineered synthetic gene sequences. With its modular workflow design and numerous graphical user interfaces, Gene Composer enables researchers to perform all common bio-informatics steps used in modern structure guided protein engineering and synthetic gene engineering. Results An interactive Alignment Viewer allows the researcher to simultaneously visualize sequence conservation in the context of known protein secondary structure, ligand contacts, water contacts, crystal contacts, B-factors, solvent accessible area, residue property type and several other useful property views. The Construct Design Module enables the facile design of novel protein constructs with altered N- and C-termini, internal insertions or deletions, point mutations, and desired affinity tags. The modifications can be combined and permuted into multiple protein constructs, and then virtually cloned in silico into defined expression vectors. The Gene Design Module uses a protein-to-gene algorithm that automates the back-translation of a protein amino acid sequence into a codon engineered nucleic acid gene sequence according to a selected codon usage table with minimal codon usage threshold, defined G:C% content, and desired sequence features achieved through synonymous codon selection that is optimized for the intended expression system. The gene-to-oligo algorithm of the Gene Design Module plans out all of the required overlapping oligonucleotides and mutagenic primers needed to synthesize the desired gene constructs by PCR, and for physically cloning them into selected vectors by the most popular subcloning strategies. Conclusion We present a complete description of Gene Composer functionality, and an efficient PCR-based synthetic gene assembly procedure with mis-match specific endonuclease error correction in combination with PIPE cloning. In a sister manuscript we present data on how Gene Composer designed genes and protein constructs can result in improved protein production for structural studies. PMID:19383142

Gene composer: database software for protein construct design, codon engineering, and gene synthesis.

PubMed

Lorimer, Don; Raymond, Amy; Walchli, John; Mixon, Mark; Barrow, Adrienne; Wallace, Ellen; Grice, Rena; Burgin, Alex; Stewart, Lance

2009-04-21

To improve efficiency in high throughput protein structure determination, we have developed a database software package, Gene Composer, which facilitates the information-rich design of protein constructs and their codon engineered synthetic gene sequences. With its modular workflow design and numerous graphical user interfaces, Gene Composer enables researchers to perform all common bio-informatics steps used in modern structure guided protein engineering and synthetic gene engineering. An interactive Alignment Viewer allows the researcher to simultaneously visualize sequence conservation in the context of known protein secondary structure, ligand contacts, water contacts, crystal contacts, B-factors, solvent accessible area, residue property type and several other useful property views. The Construct Design Module enables the facile design of novel protein constructs with altered N- and C-termini, internal insertions or deletions, point mutations, and desired affinity tags. The modifications can be combined and permuted into multiple protein constructs, and then virtually cloned in silico into defined expression vectors. The Gene Design Module uses a protein-to-gene algorithm that automates the back-translation of a protein amino acid sequence into a codon engineered nucleic acid gene sequence according to a selected codon usage table with minimal codon usage threshold, defined G:C% content, and desired sequence features achieved through synonymous codon selection that is optimized for the intended expression system. The gene-to-oligo algorithm of the Gene Design Module plans out all of the required overlapping oligonucleotides and mutagenic primers needed to synthesize the desired gene constructs by PCR, and for physically cloning them into selected vectors by the most popular subcloning strategies. We present a complete description of Gene Composer functionality, and an efficient PCR-based synthetic gene assembly procedure with mis-match specific endonuclease error correction in combination with PIPE cloning. In a sister manuscript we present data on how Gene Composer designed genes and protein constructs can result in improved protein production for structural studies.

A guide to structural factors for advanced composites used on spacecraft

NASA Technical Reports Server (NTRS)

Vanwagenen, Robert

1989-01-01

The use of composite materials in spacecraft systems is constantly increasing. Although the areas of composite design and fabrication are maturing, they remain distinct from the same activities performed using conventional materials and processes. This has led to some confusion regarding the precise meaning of the term 'factor of safety' as it applies to these structures. In addition, composite engineering introduces terms such as 'knock-down factors' to further modify material properties for design purposes. This guide is intended to clarify these terms as well as their use in the design of composite structures for spacecraft. It is particularly intended to be used by the engineering community not involved in the day-to-day composites design process. An attempt is also made to explain the wide range of factors of safety encountered in composite designs as well as their relationship to the 1.4 factor of safety conventionally applied to metallic structures.

Nuclear thermal propulsion engine system design analysis code development

NASA Astrophysics Data System (ADS)

Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.; Ivanenok, Joseph F.

1992-01-01

A Nuclear Thermal Propulsion (NTP) Engine System Design Analyis Code has recently been developed to characterize key NTP engine system design features. Such a versatile, standalone NTP system performance and engine design code is required to support ongoing and future engine system and vehicle design efforts associated with proposed Space Exploration Initiative (SEI) missions of interest. Key areas of interest in the engine system modeling effort were the reactor, shielding, and inclusion of an engine multi-redundant propellant pump feed system design option. A solid-core nuclear thermal reactor and internal shielding code model was developed to estimate the reactor's thermal-hydraulic and physical parameters based on a prescribed thermal output which was integrated into a state-of-the-art engine system design model. The reactor code module has the capability to model graphite, composite, or carbide fuels. Key output from the model consists of reactor parameters such as thermal power, pressure drop, thermal profile, and heat generation in cooled structures (reflector, shield, and core supports), as well as the engine system parameters such as weight, dimensions, pressures, temperatures, mass flows, and performance. The model's overall analysis methodology and its key assumptions and capabilities are summarized in this paper.

Structural tailoring of engine blades (STAEBL)

NASA Technical Reports Server (NTRS)

Platt, C. E.; Pratt, T. K.; Brown, K. W.

1982-01-01

A mathematical optimization procedure was developed for the structural tailoring of engine blades and was used to structurally tailor two engine fan blades constructed of composite materials without midspan shrouds. The first was a solid blade made from superhybrid composites, and the second was a hollow blade with metal matrix composite inlays. Three major computerized functions were needed to complete the procedure: approximate analysis with the established input variables, optimization of an objective function, and refined analysis for design verification.

Design optimization studies using COSMIC NASTRAN

NASA Technical Reports Server (NTRS)

Pitrof, Stephen M.; Bharatram, G.; Venkayya, Vipperla B.

1993-01-01

The purpose of this study is to create, test and document a procedure to integrate mathematical optimization algorithms with COSMIC NASTRAN. This procedure is very important to structural design engineers who wish to capitalize on optimization methods to ensure that their design is optimized for its intended application. The OPTNAST computer program was created to link NASTRAN and design optimization codes into one package. This implementation was tested using two truss structure models and optimizing their designs for minimum weight, subject to multiple loading conditions and displacement and stress constraints. However, the process is generalized so that an engineer could design other types of elements by adding to or modifying some parts of the code.

Multidisciplinary Analysis of a Hypersonic Engine

NASA Technical Reports Server (NTRS)

Suresh, Ambady; Stewart, Mark

2003-01-01

The objective is to develop high fidelity tools that can influence ISTAR design In particular, tools for coupling Fluid-Thermal-Structural simulations RBCC/TBCC designers carefully balance aerodynamic, thermal, weight, & structural considerations; consistent multidisciplinary solutions reveal details (at modest cost) At Scram mode design point, simulations give details of inlet & combustor performance, thermal loads, structural deflections.

The 1990-1991 project summaries

NASA Technical Reports Server (NTRS)

1991-01-01

Georgia Tech's School of Textile & Fiber Engineering and School of Mechanical Engineering participated in four cooperative design efforts this year. One group designed a thermal shield for a lunar telescope. The second group designed a selenotextile habitat shielding structure. The third group designed a pneumatically assisted elbow joint for the NASA zero-prebreathe suit (ZPS). The final group designed an electromechanical system to power an astronaut's finger joints. Summaries of these projects are presented.

The 1990-1991 project summaries

NASA Astrophysics Data System (ADS)

Georgia Tech's School of Textile & Fiber Engineering and School of Mechanical Engineering participated in four cooperative design efforts this year. One group designed a thermal shield for a lunar telescope. The second group designed a selenotextile habitat shielding structure. The third group designed a pneumatically assisted elbow joint for the NASA zero-prebreathe suit (ZPS). The final group designed an electromechanical system to power an astronaut's finger joints. Summaries of these projects are presented.

Biomimetic stratified scaffold design for ligament-to-bone interface tissue engineering.

PubMed

Lu, Helen H; Spalazzi, Jeffrey P

2009-07-01

The emphasis in the field of orthopaedic tissue engineering is on imparting biomimetic functionality to tissue engineered bone or soft tissue grafts and enabling their translation to the clinic. A significant challenge in achieving extended graft functionality is engineering the biological fixation of these grafts with each other as well as with the host environment. Biological fixation will require re-establishment of the structure-function relationship inherent at the native soft tissue-to-bone interface on these tissue engineered grafts. To this end, strategic biomimicry must be incorporated into advanced scaffold design. To facilitate integration between distinct tissue types (e.g., bone with soft tissues such as cartilage, ligament, or tendon), a stratified or multi-phasic scaffold with distinct yet continuous tissue regions is required to pre-engineer the interface between bone and soft tissues. Using the ACL-to-bone interface as a model system, this review outlines the strategies for stratified scaffold design for interface tissue engineering, focusing on identifying the relevant design parameters derived from an understanding of the structure-function relationship inherent at the soft-to-hard tissue interface. The design approach centers on first addressing the challenge of soft tissue-to-bone integration ex vivo, and then subsequently focusing on the relatively less difficult task of bone-to-bone integration in vivo. In addition, we will review stratified scaffold design aimed at exercising spatial control over heterotypic cellular interactions, which are critical for facilitating the formation and maintenance of distinct yet continuous multi-tissue regions. Finally, potential challenges and future directions in this emerging area of advanced scaffold design will be discussed.

Social Network Theory in Engineering Education

NASA Astrophysics Data System (ADS)

Simon, Peter A.

Collaborative groups are important both in the learning environment of engineering education and, in the real world, the business of engineering design. Selecting appropriate individuals to form an effective group and monitoring a group's progress are important aspects of successful task performance. This exploratory study looked at using the concepts of cognitive social structures, structural balance, and centrality from social network analysis as well as the measures of emotional intelligence. The concepts were used to analyze potential team members to examine if an individual's ability to perceive emotion in others and the self and to use, understand, and manage those emotions are a factor in a group's performance. The students from a capstone design course in computer engineering were used as volunteer subjects. They were formed into groups and assigned a design exercise to determine whether and which of the above-mentioned tools would be effective in both selecting teams and predicting the quality of the resultant design. The results were inconclusive with the exception of an individual's ability to accurately perceive emotions. The instruments that were successful were the Self-Monitoring scale and the accuracy scores derived from cognitive social structures and Level IV of network levels of analysis.

Energy Efficient Engine Flight Propulsion System Preliminary Analysis and Design Report

NASA Technical Reports Server (NTRS)

Bisset, J. W.; Howe, D. C.

1983-01-01

The final design and analysis of the flight propulsion system is presented. This system is the conceptual study engine defined to meet the performance, economic and environmental goals established for the Energy Efficient Engine Program. The design effort included a final definition of the engine, major components, internal subsystems, and nacelle. Various analytical representations and results from component technology programs are used to verify aerodynamic and structural design concepts and to predict performance. Specific design goals and specifications, reflecting future commercial aircraft propulsion system requirements for the mid-1980's, are detailed by NASA and used as guidelines during engine definition. Information is also included which details salient results from a separate study to define a turbofan propulsion system, known as the maximum efficiency engine, which reoptimized the advanced fuel saving technologies for improved fuel economy and direct operating costs relative to the flight propulsion system.

Crew Launch Vehicle (CLV) Upper Stage Configuration Selection Process

NASA Technical Reports Server (NTRS)

Davis, Daniel J.; Coook, Jerry R.

2006-01-01

The Crew Launch Vehicle (CLV), a key component of NASA's blueprint for the next generation of spacecraft to take humans back to the moon, is being designed and built by engineers at NASA s Marshall Space Flight Center (MSFC). The vehicle s design is based on the results of NASA's 2005 Exploration Systems Architecture Study (ESAS), which called for development of a crew-launch system to reduce the gap between Shuttle retirement and Crew Exploration Vehicle (CEV) Initial Operating Capability, identification of key technologies required to enable and significantly enhance these reference exploration systems, and a reprioritization of near- and far-term technology investments. The Upper Stage Element (USE) of the CLV is a clean-sheet approach that is being designed and developed in-house, with element management at MSFC. The USE concept is a self-supporting cylindrical structure, approximately 115' long and 216" in diameter, consisting of the following subsystems: Primary Structures (LOX Tank, LH2 Tank, Intertank, Thrust Structure, Spacecraft Payload Adaptor, Interstage, Forward and Aft Skirts), Secondary Structures (Systems Tunnel), Avionics and Software, Main Propulsion System, Reaction Control System, Thrust Vector Control, Auxiliary Power Unit, and Hydraulic Systems. The ESAS originally recommended a CEV to be launched atop a four-segment Space Shuttle Main Engine (SSME) CLV, utilizing an RS-25 engine-powered upper stage. However, Agency decisions to utilize fewer CLV development steps to lunar missions, reduce the overall risk for the lunar program, and provide a more balanced engine production rate requirement prompted engineers to switch to a five-segment design with a single Saturn-derived J-2X engine. This approach provides for single upper stage engine development for the CLV and an Earth Departure Stage, single Reusable Solid Rocket Booster (RSRB) development for the CLV and a Cargo Launch Vehicle, and single core SSME development. While the RSRB design has changed since the CLV Project's inception, the USE design has remained essentially a clean-sheet approach. Although a clean-sheet upper stage design inherently carries more risk than a modified design, it does offer many advantages: a design for increased reliability; built-in extensibility to allow for commonality/growth without major redesign; and incorporation of state-of-the-art materials, hardware, and design, fabrication, and test techniques and processes to facilitate a potentially better, more reliable system. Because consideration was given in the ESAS to both clean-sheet and modified USE designs, this paper will highlight the advantages and disadvantages of both approaches and provide a detailed discussion of trades/selections made that led to the final upper stage configuration.

Nonlinear Control of a Reusable Rocket Engine for Life Extension

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.; Holmes, Michael S.; Ray, Asok

1998-01-01

This paper presents the conceptual development of a life-extending control system where the objective is to achieve high performance and structural durability of the plant. A life-extending controller is designed for a reusable rocket engine via damage mitigation in both the fuel (H2) and oxidizer (O2) turbines while achieving high performance for transient responses of the combustion chamber pressure and the O2/H2 mixture ratio. The design procedure makes use of a combination of linear and nonlinear controller synthesis techniques and also allows adaptation of the life-extending controller module to augment a conventional performance controller of the rocket engine. The nonlinear aspect of the design is achieved using non-linear parameter optimization of a prescribed control structure. Fatigue damage in fuel and oxidizer turbine blades is primarily caused by stress cycling during start-up, shutdown, and transient operations of a rocket engine. Fatigue damage in the turbine blades is one of the most serious causes for engine failure.

Issues and Strategies in Solving Multidisciplinary Optimization Problems

NASA Technical Reports Server (NTRS)

Patnaik, Surya

2013-01-01

Optimization research at NASA Glenn Research Center has addressed the design of structures, aircraft and airbreathing propulsion engines. The accumulated multidisciplinary design activity is collected under a testbed entitled COMETBOARDS. Several issues were encountered during the solution of the problems. Four issues and the strategies adapted for their resolution are discussed. This is followed by a discussion on analytical methods that is limited to structural design application. An optimization process can lead to an inefficient local solution. This deficiency was encountered during design of an engine component. The limitation was overcome through an augmentation of animation into optimization. Optimum solutions obtained were infeasible for aircraft and airbreathing propulsion engine problems. Alleviation of this deficiency required a cascading of multiple algorithms. Profile optimization of a beam produced an irregular shape. Engineering intuition restored the regular shape for the beam. The solution obtained for a cylindrical shell by a subproblem strategy converged to a design that can be difficult to manufacture. Resolution of this issue remains a challenge. The issues and resolutions are illustrated through a set of problems: Design of an engine component, Synthesis of a subsonic aircraft, Operation optimization of a supersonic engine, Design of a wave-rotor-topping device, Profile optimization of a cantilever beam, and Design of a cylindrical shell. This chapter provides a cursory account of the issues. Cited references provide detailed discussion on the topics. Design of a structure can also be generated by traditional method and the stochastic design concept. Merits and limitations of the three methods (traditional method, optimization method and stochastic concept) are illustrated. In the traditional method, the constraints are manipulated to obtain the design and weight is back calculated. In design optimization, the weight of a structure becomes the merit function with constraints imposed on failure modes and an optimization algorithm is used to generate the solution. Stochastic design concept accounts for uncertainties in loads, material properties, and other parameters and solution is obtained by solving a design optimization problem for a specified reliability. Acceptable solutions can be produced by all the three methods. The variation in the weight calculated by the methods was found to be modest. Some variation was noticed in designs calculated by the methods. The variation may be attributed to structural indeterminacy. It is prudent to develop design by all three methods prior to its fabrication. The traditional design method can be improved when the simplified sensitivities of the behavior constraint is used. Such sensitivity can reduce design calculations and may have a potential to unify the traditional and optimization methods. Weight versus reliability traced out an inverted-S-shaped graph. The center of the graph corresponded to mean valued design. A heavy design with weight approaching infinity could be produced for a near-zero rate of failure. Weight can be reduced to a small value for a most failure-prone design. Probabilistic modeling of load and material properties remained a challenge.

The application of SSADM to modelling the logical structure of proteins.

PubMed

Saldanha, J; Eccles, J

1991-10-01

A logical design that describes the overall structure of proteins, together with a more detailed design describing secondary and some supersecondary structures, has been constructed using the computer-aided software engineering (CASE) tool, Auto-mate. Auto-mate embodies the philosophy of the Structured Systems Analysis and Design Method (SSADM) which enables the logical design of computer systems. Our design will facilitate the building of large information systems, such as databases and knowledgebases in the field of protein structure, by the derivation of system requirements from our logical model prior to producing the final physical system. In addition, the study has highlighted the ease of employing SSADM as a formalism in which to conduct the transferral of concepts from an expert into a design for a knowledge-based system that can be implemented on a computer (the knowledge-engineering exercise). It has been demonstrated how SSADM techniques may be extended for the purpose of modelling the constituent Prolog rules. This facilitates the integration of the logical system design model with the derived knowledge-based system.

Design of structures against fire. Civil engineering/buildings, architecture

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

Anchor, R.D.; Malhotra, H.L.; Purkiss, J.A.

1986-01-01

The book covers structural design criteria, along with background theory on fire protection methods for structures from a variety of materials, including timber, steel, and concrete. Research on the behavior of structural materials in the presence of fire is highlighted, and the need for fire-resistant materials is addressed.

Developing a framework for qualitative engineering: Research in design and analysis of complex structural systems

NASA Technical Reports Server (NTRS)

Franck, Bruno M.

1990-01-01

The research is focused on automating the evaluation of complex structural systems, whether for the design of a new system or the analysis of an existing one, by developing new structural analysis techniques based on qualitative reasoning. The problem is to identify and better understand: (1) the requirements for the automation of design, and (2) the qualitative reasoning associated with the conceptual development of a complex system. The long-term objective is to develop an integrated design-risk assessment environment for the evaluation of complex structural systems. The scope of this short presentation is to describe the design and cognition components of the research. Design has received special attention in cognitive science because it is now identified as a problem solving activity that is different from other information processing tasks (1). Before an attempt can be made to automate design, a thorough understanding of the underlying design theory and methodology is needed, since the design process is, in many cases, multi-disciplinary, complex in size and motivation, and uses various reasoning processes involving different kinds of knowledge in ways which vary from one context to another. The objective is to unify all the various types of knowledge under one framework of cognition. This presentation focuses on the cognitive science framework that we are using to represent the knowledge aspects associated with the human mind's abstraction abilities and how we apply it to the engineering knowledge and engineering reasoning in design.

Proceedings of the Annual Ada Software Engineering Education and Training Symposium (6th), Held in Alexandria, Virginia on September 11-13, 1991

DTIC Science & Technology

1991-09-01

level are, by necessity, designed to be accomplished by one or a few students in the course of a single academic term. Moreover, the software is seldom...that are covered in Computer Science curricula today, but with more of an engineering structure added. A stronger engineering design component is...ing, and sound software design principles found throughout Ada, and they are unambiguously specified. These are not features which were grafted onto a

Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

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

Bruce G. Schnitzler; Stanley K. Borowski

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of both the Strategic Defense Initiative (SDI) and Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified asmore » the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine operations and the engine and stage design were constrained to fit within the payload volume of the then planned space shuttle. The SNRE core design utilized hexagonal fuel elements and hexagonal structural support elements. The total number of elements can be varied to achieve engine designs of higher or lower thrust levels. Some variation in the ratio of fuel elements to structural elements is also possible. Options for SNRE-based engine designs in the 25,000-lbf thrust range were described in a recent (2010) Joint Propulsion Conference paper. The reported designs met or exceeded the performance characteristics baselined in the DRA 5.0 Study. Lower thrust SNRE-based designs were also described in a recent (2011) Joint Propulsion Conference paper. Recent activities have included parallel evaluation and design efforts on fast spectrum engines employing refractory metal alloy fuels. These efforts include evaluation of both heritage designs from the Argonne National Laboratory (ANL) and General Electric Company GE-710 Programs as well as more recent designs. Results are presented for a number of not-yet optimized fast spectrum engine options.« less

Small Fast Spectrum Reactor Designs Suitable for Direct Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Schnitzler, Bruce G.; Borowski, Stanley K.

2012-01-01

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. Past studies, in particular those in support of the Space Exploration Initiative (SEI), have shown nuclear thermal propulsion systems provide superior performance for high mass high propulsive delta-V missions. The recent NASA Design Reference Architecture (DRA) 5.0 Study re-examined mission, payload, and transportation system requirements for a human Mars landing mission in the post-2030 timeframe. Nuclear thermal propulsion was again identified as the preferred in-space transportation system. A common nuclear thermal propulsion stage with three 25,000-lbf thrust engines was used for all primary mission maneuvers. Moderately lower thrust engines may also have important roles. In particular, lower thrust engine designs demonstrating the critical technologies that are directly extensible to other thrust levels are attractive from a ground testing perspective. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. Both graphite and refractory metal alloy fuel types were pursued. Reactors and engines employing graphite based fuels were designed, built and ground tested. A number of fast spectrum reactor and engine designs employing refractory metal alloy fuel types were proposed and designed, but none were built. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art graphite based fuel design incorporating lessons learned from the very successful technology development program. The SNRE was a nominal 16,000-lbf thrust engine originally intended for unmanned applications with relatively short engine operations and the engine and stage design were constrained to fit within the payload volume of the then planned space shuttle. The SNRE core design utilized hexagonal fuel elements and hexagonal structural support elements. The total number of elements can be varied to achieve engine designs of higher or lower thrust levels. Some variation in the ratio of fuel elements to structural elements is also possible. Options for SNRE-based engine designs in the 25,000-lbf thrust range were described in a recent (2010) Joint Propulsion Conference paper. The reported designs met or exceeded the performance characteristics baselined in the DRA 5.0 Study. Lower thrust SNRE-based designs were also described in a recent (2011) Joint Propulsion Conference paper. Recent activities have included parallel evaluation and design efforts on fast spectrum engines employing refractory metal alloy fuels. These efforts include evaluation of both heritage designs from the Argonne National Laboratory (ANL) and General Electric Company GE-710 Programs as well as more recent designs. Results are presented for a number of not-yet optimized fast spectrum engine options.

Energy efficient engine preliminary design and integration study

NASA Technical Reports Server (NTRS)

Gray, D. E.

1978-01-01

The technology and configurational requirements of an all new 1990's energy efficient turbofan engine having a twin spool arrangement with a directly coupled fan and low-pressure turbine, a mixed exhaust nacelle, and a high 38.6:1 overall pressure ratio were studied. Major advanced technology design features required to provide the overall benefits were a high pressure ratio compression system, a thermally actuated advanced clearance control system, lightweight shroudless fan blades, a low maintenance cost one-stage high pressure turbine, a short efficient mixer and structurally integrated engine and nacelle. A conceptual design analysis was followed by integration and performance analyses of geared and direct-drive fan engines with separate or mixed exhaust nacelles to refine previously designed engine cycles. Preliminary design and more detailed engine-aircraft integration analysis were then conducted on the more promising configurations. Engine and aircraft sizing, fuel burned, and airframe noise studies on projected 1990's domestic and international aircraft produced sufficient definition of configurational and advanced technology requirements to allow immediate initiation of component technology development.

Instructional design considerations promoting engineering design self-efficacy

NASA Astrophysics Data System (ADS)

Jackson, Andrew M.

Engineering design activities are frequently included in technology and engineering classrooms. These activities provide an open-ended context for practicing critical thinking, problem solving, creativity, and innovation---collectively part of the 21st Century Skills which are increasingly needed for success in the workplace. Self-efficacy is a perceptual belief that impacts learning and behavior. It has been shown to directly impact each of these 21st Century Skills but its relation to engineering design is only recently being studied. The purpose of this study was to examine how instructional considerations made when implementing engineering design activities might affect student self-efficacy outcomes in a middle school engineering classroom. Student responses to two self-efficacy inventories related to design, the Engineering Design Self-Efficacy Instrument and Creative Thinking Self-Efficacy Inventory, were collected before and after participation in an engineering design curriculum. Students were also answered questions on specific factors of their experience during the curriculum which teachers may exhibit control over: teamwork and feedback. Results were analyzed using Pearson's correlation coefficients, paired and independent t-tests, and structural equation modeling to better understand patterns for self-efficacy beliefs in students. Results suggested that design self-efficacy and creative thinking self-efficacy are significantly correlated, r(1541) = .783, p < .001, and increased following participation in a design curriculum, M diff = 1.32, t(133) = 7.60, p < .001 and Mdiff = 0.79, t(124) = 4.19, p < .001 respectively. Structural models also showed that students perceive team inclusion and feedback as significant contributors to their self-efficacy beliefs, while team diversity was not related to self-efficacy. Separate models for each predictor demonstrated good fit. Recommendations are made based on the corresponding nature of engineering design self-efficacy and creative thinking self-efficacy: strategies encouraging self-efficacy in these domains may be transferrable. Instructors are made aware of the significant impact of classroom strategies for increasing self-efficacy and given specific recommendations related to teamwork and feedback to support students. Finally, although there were weaknesses in the study related to the survey administration, future research opportunities are presented which may build from this work.

Engineering of the Magnetized Target Fusion Propulsion System

NASA Technical Reports Server (NTRS)

Statham, G.; White, S.; Adams, R. B.; Thio, Y. C. F.; Santarius, J.; Alexander, R.; Fincher, S.; Polsgrove, T.; Chapman, J.; Philips, A.

2002-01-01

Engineering details are presented for a magnetized target fusion (MTF) propulsion system designed to support crewed missions to the outer solar system. Structural, thermal and radiation-management design details are presented. Propellant storage and supply options are also discussed and a propulsion system mass estimate is given.

Molecular Structure of Photosynthetic Microbial Biofuels for Improved Engine Combustion and Emissions Characteristics

PubMed Central

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes. PMID:25941673

Molecular structure of photosynthetic microbial biofuels for improved engine combustion and emissions characteristics.

PubMed

Hellier, Paul; Purton, Saul; Ladommatos, Nicos

2015-01-01

The metabolic engineering of photosynthetic microbes for production of novel hydrocarbons presents an opportunity for development of advanced designer biofuels. These can be significantly more sustainable, throughout the production-to-consumption lifecycle, than the fossil fuels and crop-based biofuels they might replace. Current biofuels, such as bioethanol and fatty acid methyl esters, have been developed primarily as drop-in replacements for existing fossil fuels, based on their physical properties and autoignition characteristics under specific combustion regimes. However, advances in the genetic engineering of microalgae and cyanobacteria, and the application of synthetic biology approaches offer the potential of designer strains capable of producing hydrocarbons and oxygenates with specific molecular structures. Furthermore, these fuel molecules can be designed for higher efficiency of energy release and lower exhaust emissions during combustion. This paper presents a review of potential fuel molecules from photosynthetic microbes and the performance of these possible fuels in modern internal combustion engines, highlighting which modifications to the molecular structure of such fuels may enhance their suitability for specific combustion regimes.

Computer-aided design of microvasculature systems for use in vascular scaffold production.

PubMed

Mondy, William Lafayette; Cameron, Don; Timmermans, Jean-Pierre; De Clerck, Nora; Sasov, Alexander; Casteleyn, Christophe; Piegl, Les A

2009-09-01

In vitro biomedical engineering of intact, functional vascular networks, which include capillary structures, is a prerequisite for adequate vascular scaffold production. Capillary structures are necessary since they provide the elements and compounds for the growth, function and maintenance of 3D tissue structures. Computer-aided modeling of stereolithographic (STL) micro-computer tomographic (micro-CT) 3D models is a technique that enables us to mimic the design of vascular tree systems containing capillary beds, found in tissues. In our first paper (Mondy et al 2009 Tissue Eng. at press), using micro-CT, we studied the possibility of using vascular tissues to produce data capable of aiding the design of vascular tree scaffolding, which would help in the reverse engineering of a complete vascular tree system including capillary bed structures. In this paper, we used STL models of large datasets of computer-aided design (CAD) data of vascular structures which contained capillary structures that mimic those in the dermal layers of rabbit skin. Using CAD software we created from 3D STL models a bio-CAD design for the development of capillary-containing vascular tree scaffolding for skin. This method is designed to enhance a variety of therapeutic protocols including, but not limited to, organ and tissue repair, systemic disease mediation and cell/tissue transplantation therapy. Our successful approach to in vitro vasculogenesis will allow the bioengineering of various other types of 3D tissue structures, and as such greatly expands the potential applications of biomedical engineering technology into the fields of biomedical research and medicine.

AiResearch QCGAT engine, airplane, and nacelle design features

NASA Technical Reports Server (NTRS)

Heldenbrand, R. W.

1980-01-01

The quiet, clean, general aviation turbofan engine and nacelle system was designed and tested. The engine utilized the core of the AiResearch model TFE731-3 engine and incorporated several unique noise- and emissions-reduction features. Components that were successfully adapted to this core include the fan, gearbox, combustor, low-pressure turbine, and associated structure. A highly versatile workhorse nacelle incorporating interchangeable acoustic and hardwall duct liners, showed that large-engine attenuation technology could be applied to small propulsion engines. The application of the mixer compound nozzle demonstrated both performance and noise advantages on the engine. Major performance, emissions, and noise goals were demonstrated.

An optimal design of wind turbine and ship structure based on neuro-response surface method

NASA Astrophysics Data System (ADS)

Lee, Jae-Chul; Shin, Sung-Chul; Kim, Soo-Young

2015-07-01

The geometry of engineering systems affects their performances. For this reason, the shape of engineering systems needs to be optimized in the initial design stage. However, engineering system design problems consist of multi-objective optimization and the performance analysis using commercial code or numerical analysis is generally time-consuming. To solve these problems, many engineers perform the optimization using the approximation model (response surface). The Response Surface Method (RSM) is generally used to predict the system performance in engineering research field, but RSM presents some prediction errors for highly nonlinear systems. The major objective of this research is to establish an optimal design method for multi-objective problems and confirm its applicability. The proposed process is composed of three parts: definition of geometry, generation of response surface, and optimization process. To reduce the time for performance analysis and minimize the prediction errors, the approximation model is generated using the Backpropagation Artificial Neural Network (BPANN) which is considered as Neuro-Response Surface Method (NRSM). The optimization is done for the generated response surface by non-dominated sorting genetic algorithm-II (NSGA-II). Through case studies of marine system and ship structure (substructure of floating offshore wind turbine considering hydrodynamics performances and bulk carrier bottom stiffened panels considering structure performance), we have confirmed the applicability of the proposed method for multi-objective side constraint optimization problems.

Implementation of civionics in a second generation steel-free bridge deck

NASA Astrophysics Data System (ADS)

Klowak, Chad; Rivera, Evangeline; Mufti, Aftab

2005-05-01

As the design and construction of civil structures continue to evolve, it is becoming imperative that these structures be monitored for their health. In order to meet this need, the discipline of Civionics has emerged. Civionics is a new term coined from Civil-Electronics, which is derived from the application of electronics to civil structures. It is similar to the term Avionics, which is used in the aerospace industry. If structural health monitoring is to become part of civil structural engineering, it should include Civionics. It involves the application of electronics to civil structures and aims to assist engineers in realizing the full benefits of structural health monitoring (SHM). In past SHM field applications, the main reason for the failure of a sensor was not the installation of the sensor itself but the egress of the sensor cables. Often, the cables were not handled and protected correctly. For SHM to be successful, specifications must be written on the entire process, beginning with system design and concluding with data collection, interpretation, and management. Civionics specifications include the technical requirements for a SHM system which encompasses fibre optic sensors, cables, conduits, junction boxes and the control room. A specification for data collection and storage is currently being developed as well. In the spring of 2004 research engineers at the University of Manitoba constructed a full-scale second generation steel free bridge deck. The bridge deck is the first of its kind to fully incorporate a complete civionics structural health monitoring system to monitor the deck's behaviour during destructive testing. Throughout the construction of the bridge deck, the entire installation of the civionics system was carried out by research engineers simulating an actual implementation of such a system in a large scale construction environment. One major concern that consulting engineers have raised is the impact that a civionics system that uses conduit, junction boxes, and other electrical ancillary protection, will have when embedded and installed externally on full-scale infrastructure. The full-scale destructive testing of a second generation steel-free bridge deck using a civionics system designed and implemented following guidelines in a civioncs specification manual at the University of Manitoba will provide engineers with the information necessary to address the constructability and structural integrity issues. Civioncs combined with structural health monitoring will provide engineers with feedback necessary to aid in optimizing design techniques and understanding our infrastructures performance, behaviour and state of condition.

ENGINEERING AND CONSTRUCTING THE HALLAM NUCLEAR POWER FACILITY REACTOR STRUCTURE

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

Mahlmeister, J E; Haberer, W V; Casey, D F

1960-12-15

The Hallam Nuclear Power Facility reactor structure, including the cavity liner, is described, and the design philosophy and special design requirements which were developed during the preliminary and final engineering phases of the project are explained. The structure was designed for 600 deg F inlet and 1000 deg F outlet operating sodium temperatures and fabricated of austenitic and ferritic stainless steels. Support for the reactor core components and adequate containment for biological safeguards were readily provided even though quite conservative design philosophy was used. The calculated operating characteristics, including heat generation, temperature distributions and stress levels for full-power operation, aremore » summarized. Ship fabrication and field installation experiences are also briefly related. Results of this project have established that the sodium graphite reactor permits practical and economical fabrication and field erection procedures; considerably higher operating design temperatures are believed possible without radical design changes. Also, larger reactor structures can be similarly constructed for higher capacity (300 to 1000 Mwe) nuclear power plants. (auth)« less

SAFAS: Unifying Form and Structure through Interactive 3D Simulation

ERIC Educational Resources Information Center

Polys, Nicholas F.; Bacim, Felipe; Setareh, Mehdi; Jones, Brett D.

2015-01-01

There has been a significant gap between the tools used for the design of a building's architectural form and those that evaluate the structural physics of that form. Seeking to bring the perspectives of visual design and structural engineering closer together, we developed and evaluated a design tool for students and practitioners to explore the…

Interdisciplinary research and development on the effects of the nature and properties of ceramic materials in the design of advanced structural components

NASA Technical Reports Server (NTRS)

1978-01-01

An educational development and supportive research program on ceramic materials established to advance design methodology, improve materials, and develop engineers knowledgable in design with and use of high performance ceramic materials is described. Emphasis is on the structures and related materials problems in a ceramic turbine engine, but applications in coal gasification, solar conversion, and magnetohydrodynamic technologies are considered. Progress of various research projects in the areas of new materials, processing, characterization, and nondestructive testing is reported. Fracture toughness determination, extended X-ray absorption fine structure measurements, and grain boundary effects in beta-alumina are among the topics covered.

Structural Performance’s Optimally Analysing and Implementing Based on ANSYS Technology

NASA Astrophysics Data System (ADS)

Han, Na; Wang, Xuquan; Yue, Haifang; Sun, Jiandong; Wu, Yongchun

2017-06-01

Computer-aided Engineering (CAE) is a hotspot both in academic field and in modern engineering practice. Analysis System(ANSYS) simulation software for its excellent performance become outstanding one in CAE family, it is committed to the innovation of engineering simulation to help users to shorten the design process, improve product innovation and performance. Aimed to explore a structural performance’s optimally analyzing model for engineering enterprises, this paper introduced CAE and its development, analyzed the necessity for structural optimal analysis as well as the framework of structural optimal analysis on ANSYS Technology, used ANSYS to implement a reinforced concrete slab structural performance’s optimal analysis, which was display the chart of displacement vector and the chart of stress intensity. Finally, this paper compared ANSYS software simulation results with the measured results,expounded that ANSYS is indispensable engineering calculation tools.

A design procedure for fan inflow control structures

NASA Technical Reports Server (NTRS)

Gedge, M. R.

1980-01-01

Significant differences exist in the noise generated by engine in flight and engines operating on the test stand. It was observed that these differences can be reduced by use of an inflow control structure (ICS) in the static test configuration. The results of the second phase of a three phase program are described and the results of a test program conducted to assess and modify various theoretical models, leading to the development of an ICS design system is summarized.

Designing Biomimetic Materials from Marine Organisms.

PubMed

Nichols, William T

2015-01-01

Two biomimetic design approaches that apply biological solutions to engineering problems are discussed. In the first case, motivation comes from an engineering problem and the key challenge is to find analogous biological functions and map them into engineering materials. We illustrate with an example of water pollution remediation through appropriate design of a biomimetic sponge. In the second case, a biological function is already known and the challenge is to identify the appropriate engineering problem. We demonstrate the biological approach with marine diatoms that control energy and materials at their surface providing inspiration for a number of engineering applications. In both cases, it is essential to select materials and structures at the nanoscale to control energy and materials flows at interfaces.

A case study for a digital seabed database: Bohai Sea engineering geology database

NASA Astrophysics Data System (ADS)

Tianyun, Su; Shikui, Zhai; Baohua, Liu; Ruicai, Liang; Yanpeng, Zheng; Yong, Wang

2006-07-01

This paper discusses the designing plan of ORACLE-based Bohai Sea engineering geology database structure from requisition analysis, conceptual structure analysis, logical structure analysis, physical structure analysis and security designing. In the study, we used the object-oriented Unified Modeling Language (UML) to model the conceptual structure of the database and used the powerful function of data management which the object-oriented and relational database ORACLE provides to organize and manage the storage space and improve its security performance. By this means, the database can provide rapid and highly effective performance in data storage, maintenance and query to satisfy the application requisition of the Bohai Sea Oilfield Paradigm Area Information System.

A heuristic approach to optimization of structural topology including self-weight

NASA Astrophysics Data System (ADS)

Tajs-Zielińska, Katarzyna; Bochenek, Bogdan

2018-01-01

Topology optimization of structures under a design-dependent self-weight load is investigated in this paper. The problem deserves attention because of its significant importance in the engineering practice, especially nowadays as topology optimization is more often applied when designing large engineering structures, for example, bridges or carrying systems of tall buildings. It is worth noting that well-known approaches of topology optimization which have been successfully applied to structures under fixed loads cannot be directly adapted to the case of design-dependent loads, so that topology generation can be a challenge also for numerical algorithms. The paper presents the application of a simple but efficient non-gradient method to topology optimization of elastic structures under self-weight loading. The algorithm is based on the Cellular Automata concept, the application of which can produce effective solutions with low computational cost.

Segmented molecular design of self-healing proteinaceous materials

NASA Astrophysics Data System (ADS)

Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C.

2015-09-01

Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.

Segmented molecular design of self-healing proteinaceous materials.

PubMed

Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C

2015-09-01

Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

14 CFR 23.363 - Side load on engine mount.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Side load on engine mount. 23.363 Section....363 Side load on engine mount. (a) Each engine mount and its supporting structure must be designed for a limit load factor in a lateral direction, for the side load on the engine mount, of not less than...

Design, evaluation and test of an electronic, multivariable control for the F100 turbofan engine

NASA Technical Reports Server (NTRS)

Skira, C. A.; Dehoff, R. L.; Hall, W. E., Jr.

1980-01-01

A digital, multivariable control design procedure for the F100 turbofan engine is described. The controller is based on locally linear synthesis techniques using linear, quadratic regulator design methods. The control structure uses an explicit model reference form with proportional and integral feedback near a nominal trajectory. Modeling issues, design procedures for the control law and the estimation of poorly measured variables are presented.

Design of the advanced regional aircraft, the DART-75

NASA Technical Reports Server (NTRS)

Elliott, Steve; Gislason, Jason; Huffstetler, Mark; Mann, Jon; Withers, Ashley; Zimmerman, Mark

1992-01-01

This design analysis is intended to show the capabilities of the DART-75, a 75 passenger medium-range regional transport. Included are the detailed descriptions of the structures, performance, stability and control, weight and balance, and engine design. The design should allow for the DART to become the premier regional aircraft of the future due to some advanced features like the canard, semi-composite construction, and advanced engines.

The impact of emerging technologies on an advanced supersonic transport

NASA Technical Reports Server (NTRS)

Driver, C.; Maglieri, D. J.

1986-01-01

The effects of advances in propulsion systems, structure and materials, aerodynamics, and systems on the design and development of supersonic transport aircraft are analyzed. Efficient propulsion systems with variable-cycle engines provide the basis for improved propulsion systems; the propulsion efficienies of supersonic and subsonic engines are compared. Material advances consist of long-life damage-tolerant structures, advanced material development, aeroelastic tailoring, and low-cost fabrication. Improvements in the areas of aerodynamics and systems are examined. The environmental problems caused by engine emissions, airport noise, and sonic boom are studied. The characteristics of the aircraft designed to include these technical advances are described.

Making Informed Decisions: The Role of Information Literacy in Ethical and Effective Engineering Design

ERIC Educational Resources Information Center

Fosmire, Michael

2017-01-01

Engineering designers must make evidence-based decisions when applying the practical tools and techniques of their discipline to human problems. Information literacy provides a structure for determining information gaps, locating appropriate and relevant information, applying that information effectively, and documenting and managing the knowledge…

Unit cell-based computer-aided manufacturing system for tissue engineering.

PubMed

Kang, Hyun-Wook; Park, Jeong Hun; Kang, Tae-Yun; Seol, Young-Joon; Cho, Dong-Woo

2012-03-01

Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering.

Tissue engineering: state of the art in oral rehabilitation

PubMed Central

SCHELLER, E. L.; KREBSBACH, P. H.; KOHN, D. H.

2009-01-01

SUMMARY More than 85% of the global population requires repair or replacement of a craniofacial structure. These defects range from simple tooth decay to radical oncologic craniofacial resection. Regeneration of oral and craniofacial tissues presents a formidable challenge that requires synthesis of basic science, clinical science and engineering technology. Identification of appropriate scaffolds, cell sources and spatial and temporal signals (the tissue engineering triad) is necessary to optimize development of a single tissue, hybrid organ or interface. Furthermore, combining the understanding of the interactions between molecules of the extracellular matrix and attached cells with an understanding of the gene expression needed to induce differentiation and tissue growth will provide the design basis for translating basic science into rationally developed components of this tissue engineering triad. Dental tissue engineers are interested in regeneration of teeth, oral mucosa, salivary glands, bone and periodontium. Many of these oral structures are hybrid tissues. For example, engineering the periodontium requires growth of alveolar bone, cementum and the periodontal ligament. Recapitulation of biological development of hybrid tissues and interfaces presents a challenge that exceeds that of engineering just a single tissue. Advances made in dental interface engineering will allow these tissues to serve as model systems for engineering other tissues or organs of the body. This review will begin by covering basic tissue engineering principles and strategic design of functional biomaterials. We will then explore the impact of biomaterials design on the status of craniofacial tissue engineering and current challenges and opportunities in dental tissue engineering. PMID:19228277

Tissue engineering: state of the art in oral rehabilitation.

PubMed

Scheller, E L; Krebsbach, P H; Kohn, D H

2009-05-01

More than 85% of the global population requires repair or replacement of a craniofacial structure. These defects range from simple tooth decay to radical oncologic craniofacial resection. Regeneration of oral and craniofacial tissues presents a formidable challenge that requires synthesis of basic science, clinical science and engineering technology. Identification of appropriate scaffolds, cell sources and spatial and temporal signals (the tissue engineering triad) is necessary to optimize development of a single tissue, hybrid organ or interface. Furthermore, combining the understanding of the interactions between molecules of the extracellular matrix and attached cells with an understanding of the gene expression needed to induce differentiation and tissue growth will provide the design basis for translating basic science into rationally developed components of this tissue engineering triad. Dental tissue engineers are interested in regeneration of teeth, oral mucosa, salivary glands, bone and periodontium. Many of these oral structures are hybrid tissues. For example, engineering the periodontium requires growth of alveolar bone, cementum and the periodontal ligament. Recapitulation of biological development of hybrid tissues and interfaces presents a challenge that exceeds that of engineering just a single tissue. Advances made in dental interface engineering will allow these tissues to serve as model systems for engineering other tissues or organs of the body. This review will begin by covering basic tissue engineering principles and strategic design of functional biomaterials. We will then explore the impact of biomaterials design on the status of craniofacial tissue engineering and current challenges and opportunities in dental tissue engineering.

Recent advances in convectively cooled engine and airframe structures for hypersonic flight

NASA Technical Reports Server (NTRS)

Kelly, H. N.; Wieting, A. R.; Shore, C. P.; Nowak, R. J.

1978-01-01

A hydrogen-cooled structure for a fixed-geometry, airframe-integrated scramjet is described. The thermal/structural problems, concepts, design features, and technological advances are applicable to a broad range of engines. Convectively cooled airframe structural concepts that have evolved from an extensive series of investigations, the technology developments that have led to these concepts, and the benefits that accrue from their use are discussed.

The Complex Dynamics of Student Engagement in Novel Engineering Design Activities

NASA Astrophysics Data System (ADS)

McCormick, Mary

In engineering design, making sense of "messy," design situations is at the heart of the discipline (Schon, 1983); engineers in practice bring structure to design situations by organizing, negotiating, and coordinating multiple aspects (Bucciarelli, 1994; Stevens, Johri, & O'Connor, 2014). In classroom settings, however, students are more often given well-defined, content-focused engineering tasks (Jonassen, 2014). These tasks are based on the assumption that elementary students are unable to grapple with the complexity or open-endedness of engineering design (Crismond & Adams, 2012). The data I present in this dissertation suggest the opposite. I show that students are not only able to make sense of, or frame (Goffman, 1974), complex design situations, but that their framings dynamically involve their nascent abilities for engineering design. The context of this work is Novel Engineering, a larger research project that explores using children's literature as an access point for engineering design. Novel Engineering activities are inherently messy: there are characters with needs, settings with implicit constraints, and rich design situations. In a series of three studies, I show how students' framings of Novel Engineering design activities involve their reasoning and acting as beginning engineers. In the first study, I show two students whose caring for the story characters contributes to their stability in framing the task: they identify the needs of their fictional clients and iteratively design a solution to meet their clients' needs. In the second, I show how students' shifting and negotiating framings influence their engineering assumptions and evaluation criteria. In the third, I show how students' coordinating framings involve navigating a design process to meet clients' needs, classroom expectations, and technical requirements. Collectively, these studies contribute to literature by documenting students' productive beginnings in engineering design. The implications span research and practice, specifically targeting how we attend to and support students as they engage in engineering design.

Integration of Design, Thermal, Structural, and Optical Analysis, Including Thermal Animation

NASA Technical Reports Server (NTRS)

Amundsen, Ruth M.

1993-01-01

In many industries there has recently been a concerted movement toward 'quality management' and the issue of how to accomplish work more efficiently. Part of this effort is focused on concurrent engineering; the idea of integrating the design and analysis processes so that they are not separate, sequential processes (often involving design rework due to analytical findings) but instead form an integrated system with smooth transfers of information. Presented herein are several specific examples of concurrent engineering methods being carried out at Langley Research Center (LaRC): integration of thermal, structural and optical analyses to predict changes in optical performance based on thermal and structural effects; integration of the CAD design process with thermal and structural analyses; and integration of analysis and presentation by animating the thermal response of a system as an active color map -- a highly effective visual indication of heat flow.

Artificial Symmetry-Breaking for Morphogenetic Engineering Bacterial Colonies.

PubMed

Nuñez, Isaac N; Matute, Tamara F; Del Valle, Ilenne D; Kan, Anton; Choksi, Atri; Endy, Drew; Haseloff, Jim; Rudge, Timothy J; Federici, Fernan

2017-02-17

Morphogenetic engineering is an emerging field that explores the design and implementation of self-organized patterns, morphologies, and architectures in systems composed of multiple agents such as cells and swarm robots. Synthetic biology, on the other hand, aims to develop tools and formalisms that increase reproducibility, tractability, and efficiency in the engineering of biological systems. We seek to apply synthetic biology approaches to the engineering of morphologies in multicellular systems. Here, we describe the engineering of two mechanisms, symmetry-breaking and domain-specific cell regulation, as elementary functions for the prototyping of morphogenetic instructions in bacterial colonies. The former represents an artificial patterning mechanism based on plasmid segregation while the latter plays the role of artificial cell differentiation by spatial colocalization of ubiquitous and segregated components. This separation of patterning from actuation facilitates the design-build-test-improve engineering cycle. We created computational modules for CellModeller representing these basic functions and used it to guide the design process and explore the design space in silico. We applied these tools to encode spatially structured functions such as metabolic complementation, RNAPT7 gene expression, and CRISPRi/Cas9 regulation. Finally, as a proof of concept, we used CRISPRi/Cas technology to regulate cell growth by controlling methionine synthesis. These mechanisms start from single cells enabling the study of morphogenetic principles and the engineering of novel population scale structures from the bottom up.

Development and Evaluation of TiAl Sheet Structures for Hypersonic Applications

NASA Technical Reports Server (NTRS)

Draper, S. L.; Krause, D.; Lerch, B.; Locci, I. E.; Doehnert, B.; Nigam, R.; Das, G.; Sickles, P.; Tabernig, B.; Reger, N.;

Evaluation of FCS self and peer-assessment approach based on Cooperative and Engineering Design learning.

PubMed

Cvetkovic, Dean

2013-01-01

The Cooperative Learning in Engineering Design curriculum can be enhanced with structured and timely self and peer assessment teaching methodologies which can easily be applied to any Biomedical Engineering curriculum. A study was designed and implemented to evaluate the effectiveness of this structured and timely self and peer assessment on student team-based projects. In comparing the 'peer-blind' and 'face-to-face' Fair Contribution Scoring (FCS) methods, both had advantages and disadvantages. The 'peer-blind' self and peer assessment method would cause high discrepancy between self and team ratings. But the 'face-to-face' method on the other hand did not have the discrepancy issue and had actually proved to be a more accurate and effective, indicating team cohesiveness and good cooperative learning.

Executive control systems in the engineering design environment

NASA Technical Reports Server (NTRS)

Hurst, P. W.; Pratt, T. W.

1985-01-01

Executive Control Systems (ECSs) are software structures for the unification of various engineering design application programs into comprehensive systems with a central user interface (uniform access) method and a data management facility. Attention is presently given to the most significant determinations of a research program conducted for 24 ECSs, used in government and industry engineering design environments to integrate CAD/CAE applications programs. Characterizations are given for the systems' major architectural components and the alternative design approaches considered in their development. Attention is given to ECS development prospects in the areas of interdisciplinary usage, standardization, knowledge utilization, and computer science technology transfer.

Extendable retractable telescopic mast for deployable structures

NASA Technical Reports Server (NTRS)

Schmid, M.; Aguirre, M.

1986-01-01

The Extendable and Retractable Mast (ERM) which is presently developed by Dornier in the frame of an ESA-contract, will be used to deploy and retract large foldable structures. The design is based on a telescopic carbon-fiber structure with high stiffness, strength and pointing accuracy. To verify the chosen design, a breadboard model of an ERM was built and tested under thermal vacuum (TV)-conditions. It is planned as a follow-on development to manufacture and test an Engineering Model Mast. The Engineering Model will be used to establish the basis for an ERM-family covering a wide range of requirements.

Orbit Transfer Vehicle (OTV) engine, phase A study. Volume 2: Study

NASA Technical Reports Server (NTRS)

Mellish, J. A.

1979-01-01

The hydrogen oxygen engine used in the orbiter transfer vehicle is described. The engine design is analyzed and minimum engine performance and man rating requirements are discussed. Reliability and safety analysis test results are presented and payload, risk and cost, and engine installation parameters are defined. Engine tests were performed including performance analysis, structural analysis, thermal analysis, turbomachinery analysis, controls analysis, and cycle analysis.

Optimally analyzing and implementing of bolt fittings in steel structure based on ANSYS

NASA Astrophysics Data System (ADS)

Han, Na; Song, Shuangyang; Cui, Yan; Wu, Yongchun

2018-03-01

ANSYS simulation software for its excellent performance become outstanding one in Computer-aided Engineering (CAE) family, it is committed to the innovation of engineering simulation to help users to shorten the design process. First, a typical procedure to implement CAE was design. The framework of structural numerical analysis on ANSYS Technology was proposed. Then, A optimally analyzing and implementing of bolt fittings in beam-column join of steel structure was implemented by ANSYS, which was display the cloud chart of XY-shear stress, the cloud chart of YZ-shear stress and the cloud chart of Y component of stress. Finally, ANSYS software simulating results was compared with the measured results by the experiment. The result of ANSYS simulating and analyzing is reliable, efficient and optical. In above process, a structural performance's numerical simulating and analyzing model were explored for engineering enterprises' practice.

Optimization applications in aircraft engine design and test

NASA Technical Reports Server (NTRS)

Pratt, T. K.

1984-01-01

Starting with the NASA-sponsored STAEBL program, optimization methods based primarily upon the versatile program COPES/CONMIN were introduced over the past few years to a broad spectrum of engineering problems in structural optimization, engine design, engine test, and more recently, manufacturing processes. By automating design and testing processes, many repetitive and costly trade-off studies have been replaced by optimization procedures. Rather than taking engineers and designers out of the loop, optimization has, in fact, put them more in control by providing sophisticated search techniques. The ultimate decision whether to accept or reject an optimal feasible design still rests with the analyst. Feedback obtained from this decision process has been invaluable since it can be incorporated into the optimization procedure to make it more intelligent. On several occasions, optimization procedures have produced novel designs, such as the nonsymmetric placement of rotor case stiffener rings, not anticipated by engineering designers. In another case, a particularly difficult resonance contraint could not be satisfied using hand iterations for a compressor blade, when the STAEBL program was applied to the problem, a feasible solution was obtained in just two iterations.

Optical engineering capstone design projects with industry sponsors

NASA Astrophysics Data System (ADS)

Bunch, Robert M.; Leisher, Paul O.; Granieri, Sergio C.

2014-09-01

Capstone senior design is the culmination of a student's undergraduate engineering education that prepares them for engineering practice. In fact, any engineering degree program that pursues accreditation by the Engineering Accreditation Commission of ABET must contain "a major design experience based on the knowledge and skills acquired in earlier course work and incorporating appropriate engineering standards and multiple realistic constraints." At Rose-Hulman, we offer an interdisciplinary Optical Engineering / Engineering Physics senior design curriculum that meets this requirement. Part of this curriculum is a two-course sequence where students work in teams on a design project leading to a functional prototype. The students begin work on their capstone project during the first week of their senior year. The courses are deliverable-driven and the students are held accountable for regular technical progress through weekly updates with their faculty advisor and mid-term design reviews. We have found that client-sponsored projects offer students an enriched engineering design experience as it ensures consideration of constraints and standards requirements similar to those that they will encounter as working engineers. Further, client-sponsored projects provide teams with an opportunity for regular customer interactions which help shape the product design. The process that we follow in both soliciting and helping to scope appropriate industry-related design projects will be described. In addition, an outline of the capstone course structure as well as methods used to hold teams accountable for technical milestones will be discussed. Illustrative examples of past projects will be provided.

Physical-scale models of engineered log jams in rivers

USDA-ARS?s Scientific Manuscript database

Stream restoration and river engineering projects are employing engineered log jams increasingly for stabilization and in-stream improvements. To further advance the design of these structures and their morphodynamic effects on corridors, the basis for physical-scale models of rivers with engineere...

Genetic-evolution-based optimization methods for engineering design

NASA Technical Reports Server (NTRS)

Rao, S. S.; Pan, T. S.; Dhingra, A. K.; Venkayya, V. B.; Kumar, V.

1990-01-01

This paper presents the applicability of a biological model, based on genetic evolution, for engineering design optimization. Algorithms embodying the ideas of reproduction, crossover, and mutation are developed and applied to solve different types of structural optimization problems. Both continuous and discrete variable optimization problems are solved. A two-bay truss for maximum fundamental frequency is considered to demonstrate the continuous variable case. The selection of locations of actuators in an actively controlled structure, for minimum energy dissipation, is considered to illustrate the discrete variable case.

Predictive design procedures, VESYS users manual : an interim design method for flexible pavements using the VESYS structural subsystem

DOT National Transportation Integrated Search

1978-01-01

This manual has been written to provide the pavement manager and design engineer with a ready reference of procedures to predict the structural responses and hence the integrity of flexible pavements. A pavement section of known geometry is chosen, a...

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.

Engineering the Future.

ERIC Educational Resources Information Center

Finniston, Monty

1985-01-01

Describes several key characteristics of professionalism and an engineering education curriculum which focuses on developing professionalism. The entrance course, teaching design, structured training, and continuing development are among the curricular areas addressed. (JN)

DataRocket: Interactive Visualisation of Data Structures

NASA Astrophysics Data System (ADS)

Parkes, Steve; Ramsay, Craig

2010-08-01

CodeRocket is a software engineering tool that provides cognitive support to the software engineer for reasoning about a method or procedure and for documenting the resulting code [1]. DataRocket is a software engineering tool designed to support visualisation and reasoning about program data structures. DataRocket is part of the CodeRocket family of software tools developed by Rapid Quality Systems [2] a spin-out company from the Space Technology Centre at the University of Dundee. CodeRocket and DataRocket integrate seamlessly with existing architectural design and coding tools and provide extensive documentation with little or no effort on behalf of the software engineer. Comprehensive, abstract, detailed design documentation is available early on in a project so that it can be used for design reviews with project managers and non expert stakeholders. Code and documentation remain fully synchronised even when changes are implemented in the code without reference to the existing documentation. At the end of a project the press of a button suffices to produce the detailed design document. Existing legacy code can be easily imported into CodeRocket and DataRocket to reverse engineer detailed design documentation making legacy code more manageable and adding substantially to its value. This paper introduces CodeRocket. It then explains the rationale for DataRocket and describes the key features of this new tool. Finally the major benefits of DataRocket for different stakeholders are considered.

"Science in Society, Omnibus Pack, Readers M-P."

ERIC Educational Resources Information Center

Association for Science Education, Cambridge (England).

Four additional readers have been written for use in the Science in Society general studies project. Three of the readers discuss the applications and importance of engineering in the world. They include: Engineering 1 (Reader M), which discusses such topics as the role of engineering in society, structural design and engineering, the engineering…

Multiphysics Engineering Analysis for an Integrated Design of ITER Diagnostic First Wall and Diagnostic Shield Module Design

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

Zhai, Y.; Loesser, G.; Smith, M.

ITER diagnostic first walls (DFWs) and diagnostic shield modules (DSMs) inside the port plugs (PPs) are designed to protect diagnostic instrument and components from a harsh plasma environment and provide structural support while allowing for diagnostic access to the plasma. The design of DFWs and DSMs are driven by 1) plasma radiation and nuclear heating during normal operation 2) electromagnetic loads during plasma events and associate component structural responses. A multi-physics engineering analysis protocol for the design has been established at Princeton Plasma Physics Laboratory and it was used for the design of ITER DFWs and DSMs. The analyses weremore » performed to address challenging design issues based on resultant stresses and deflections of the DFW-DSM-PP assembly for the main load cases. ITER Structural Design Criteria for In-Vessel Components (SDC-IC) required for design by analysis and three major issues driving the mechanical design of ITER DFWs are discussed. The general guidelines for the DSM design have been established as a result of design parametric studies.« less

Expert vs. novice: Problem decomposition/recomposition in engineering design

NASA Astrophysics Data System (ADS)

Song, Ting

The purpose of this research was to investigate the differences of using problem decomposition and problem recomposition among dyads of engineering experts, dyads of engineering seniors, and dyads of engineering freshmen. Fifty participants took part in this study. Ten were engineering design experts, 20 were engineering seniors, and 20 were engineering freshmen. Participants worked in dyads to complete an engineering design challenge within an hour. The entire design process was video and audio recorded. After the design session, members participated in a group interview. This study used protocol analysis as the methodology. Video and audio data were transcribed, segmented, and coded. Two coding systems including the FBS ontology and "levels of the problem" were used in this study. A series of statistical techniques were used to analyze data. Interview data and participants' design sketches also worked as supplemental data to help answer the research questions. By analyzing the quantitative and qualitative data, it was found that students used less problem decomposition and problem recomposition than engineer experts in engineering design. This result implies that engineering education should place more importance on teaching problem decomposition and problem recomposition. Students were found to spend less cognitive effort when considering the problem as a whole and interactions between subsystems than engineer experts. In addition, students were also found to spend more cognitive effort when considering details of subsystems. These results showed that students tended to use dept-first decomposition and experts tended to use breadth-first decomposition in engineering design. The use of Function (F), Behavior (B), and Structure (S) among engineering experts, engineering seniors, and engineering freshmen was compared on three levels. Level 1 represents designers consider the problem as an integral whole, Level 2 represents designers consider interactions between subsystems, and Level 3 represents designers consider details of subsystems. The results showed that students used more S on Level 1 and 3 but they used less F on Level 1 than engineering experts. The results imply that engineering curriculum should improve the teaching of problem definition in engineering design because students need to understand the problem before solving it.

24 CFR 3280.903 - General requirements for designing the structure to withstand transportation shock and vibration.

Code of Federal Regulations, 2013 CFR

2013-04-01

... manufactured home shall be designed, in terms of its structural, plumbing, mechanical and electrical systems... subsequent secondary transportation moves. (c) In place of an engineering analysis, either of the following...

24 CFR 3280.903 - General requirements for designing the structure to withstand transportation shock and vibration.

Code of Federal Regulations, 2011 CFR

2011-04-01

... manufactured home shall be designed, in terms of its structural, plumbing, mechanical and electrical systems... subsequent secondary transportation moves. (c) In place of an engineering analysis, either of the following...

24 CFR 3280.903 - General requirements for designing the structure to withstand transportation shock and vibration.

Code of Federal Regulations, 2012 CFR

2012-04-01

... manufactured home shall be designed, in terms of its structural, plumbing, mechanical and electrical systems... subsequent secondary transportation moves. (c) In place of an engineering analysis, either of the following...

24 CFR 3280.903 - General requirements for designing the structure to withstand transportation shock and vibration.

Code of Federal Regulations, 2014 CFR

2014-04-01

... manufactured home shall be designed, in terms of its structural, plumbing, mechanical and electrical systems... subsequent secondary transportation moves. (c) In place of an engineering analysis, either of the following...

Creative brains: designing in the real world†

PubMed Central

Goel, Vinod

2014-01-01

The process of designing artifacts is a creative activity. It is proposed that, at the cognitive level, one key to understanding design creativity is to understand the array of symbol systems designers utilize. These symbol systems range from being vague, imprecise, abstract, ambiguous, and indeterminate (like conceptual sketches), to being very precise, concrete, unambiguous, and determinate (like contract documents). The former types of symbol systems support associative processes that facilitate lateral (or divergent) transformations that broaden the problem space, while the latter types of symbol systems support inference processes facilitating vertical (or convergent) transformations that deepen of the problem space. The process of artifact design requires the judicious application of both lateral and vertical transformations. This leads to a dual mechanism model of design problem-solving comprising of an associative engine and an inference engine. It is further claimed that this dual mechanism model is supported by an interesting hemispheric dissociation in human prefrontal cortex. The associative engine and neural structures that support imprecise, ambiguous, abstract, indeterminate representations are lateralized in the right prefrontal cortex, while the inference engine and neural structures that support precise, unambiguous, determinant representations are lateralized in the left prefrontal cortex. At the brain level, successful design of artifacts requires a delicate balance between the two hemispheres of prefrontal cortex. PMID:24817846

Structural Analysis Made 'NESSUSary'

NASA Technical Reports Server (NTRS)

2005-01-01

Everywhere you look, chances are something that was designed and tested by a computer will be in plain view. Computers are now utilized to design and test just about everything imaginable, from automobiles and airplanes to bridges and boats, and elevators and escalators to streets and skyscrapers. Computer-design engineering first emerged in the 1970s, in the automobile and aerospace industries. Since computers were in their infancy, however, architects and engineers during the time were limited to producing only designs similar to hand-drafted drawings. (At the end of 1970s, a typical computer-aided design system was a 16-bit minicomputer with a price tag of $125,000.) Eventually, computers became more affordable and related software became more sophisticated, offering designers the "bells and whistles" to go beyond the limits of basic drafting and rendering, and venture into more skillful applications. One of the major advancements was the ability to test the objects being designed for the probability of failure. This advancement was especially important for the aerospace industry, where complicated and expensive structures are designed. The ability to perform reliability and risk assessment without using extensive hardware testing is critical to design and certification. In 1984, NASA initiated the Probabilistic Structural Analysis Methods (PSAM) project at Glenn Research Center to develop analysis methods and computer programs for the probabilistic structural analysis of select engine components for current Space Shuttle and future space propulsion systems. NASA envisioned that these methods and computational tools would play a critical role in establishing increased system performance and durability, and assist in structural system qualification and certification. Not only was the PSAM project beneficial to aerospace, it paved the way for a commercial risk- probability tool that is evaluating risks in diverse, down- to-Earth application

Software Requirements Engineering Methodology (Development)

DTIC Science & Technology

1979-06-01

Higher Order Software [20]; and the Michael Jackson Design Methodology [21]. Although structured programming constructs have proven to be more useful...reviewed here. Similarly, the manual techniques for software design (e.g., HIPO Diagrams, Nassi-Schneidermann charts, Top-Down Design, the Michael ... Jackson Design Methodology, Yourdon’s Structured Design) are not addressed. 6.1.3 Research Programs There are a number of research programs underway

Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

NASA Astrophysics Data System (ADS)

Nguyen, Q. H.; Choi, S. B.; Lee, Y. S.; Han, M. S.

2013-11-01

This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.

Optimized bio-inspired stiffening design for an engine nacelle.

PubMed

Lazo, Neil; Vodenitcharova, Tania; Hoffman, Mark

2015-11-04

Structural efficiency is a common engineering goal in which an ideal solution provides a structure with optimized performance at minimized weight, with consideration of material mechanical properties, structural geometry, and manufacturability. This study aims to address this goal in developing high performance lightweight, stiff mechanical components by creating an optimized design from a biologically-inspired template. The approach is implemented on the optimization of rib stiffeners along an aircraft engine nacelle. The helical and angled arrangements of cellulose fibres in plants were chosen as the bio-inspired template. Optimization of total displacement and weight was carried out using a genetic algorithm (GA) coupled with finite element analysis. Iterations showed a gradual convergence in normalized fitness. Displacement was given higher emphasis in optimization, thus the GA optimization tended towards individual designs with weights near the mass constraint. Dominant features of the resulting designs were helical ribs with rectangular cross-sections having large height-to-width ratio. Displacement reduction was at 73% as compared to an unreinforced nacelle, and is attributed to the geometric features and layout of the stiffeners, while mass is maintained within the constraint.

A Service Learning Structural Engineering Capstone Course and the Assessment of Technical and Non-Technical Objectives

ERIC Educational Resources Information Center

Dinehart, David W.; Gross, Shawn P.

2010-01-01

The primary role of a civil engineer is to serve the community; thus, it is essential that students understand the impact of engineering projects on, and the context of engineering projects within, society. One goal of an engineering capstone design course should be to mesh the technical knowledge of the discipline with an encompassing engineering…

Challenges for Engineering Design, Construction, and Maintenance of Infrastructure in Afghanistan

DTIC Science & Technology

2010-11-01

applied engineering expertise that collectively can solve challenging infra- structure problems. USACE-ERDC’s researchers and engineers are field...Development Center (ERDC) possesses a unique combination of basic research and applied engineering expertise that collectively can solve challenging...restoration, and other projects. The USACE Engineer Research and Development Center (ERDC) possesses a unique combination of basic research and applied

Structural Design Exploration of an Electric Powered Multi-Propulsor Wing Configuration

NASA Technical Reports Server (NTRS)

Moore, James B.; Cutright, Steve

2017-01-01

Advancements in aircraft electric propulsion may enable an expanded operational envelope for electrically powered vehicles compared to their internal combustion engine counterparts. High aspect ratio wings provide additional lift and drag reduction for a proposed multi-propulsor design, however, the challenge is to reduce the weight of wing structures while maintaining adequate structural and aeroelastic margins. Design exploration using a conventional design-and-build philosophy coupled with a finite element method (FEM)-based design of experiments (DOE) strategy are presented to examine high aspect ratio wing structures that have spanwise distributed electric motors. Multiple leading-edge-mounted engine masses presented a challenge to design a wing within acceptable limits for dynamic and aeroelastic stability. Because the first four primary bending eigenmodes of the proposed wing structure are very sensitive to outboard motor placement, safety-of-flight requirements drove the need for multiple spars, rib attachments, and outboard structural reinforcements in the design. Global aeroelasticity became an increasingly important design constraint during the on-going design process, with outboard motor pod flutter ultimately becoming a primary design constraint. Designers successively generated models to examine stress, dynamics, and aeroelasticity concurrently. This research specifically addressed satisfying multi-disciplinary design criteria to generate fluid-structure interaction solution sets, and produced high aspect ratio primary structure designs for the NASA Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) project in the Aeronautic Research Mission Directorate at NASA. In this paper, a dynamics-driven, quasi-inverse design methodology is presented to address aerodynamic performance goals and structural challenges encountered for the SCEPTOR demonstrator vehicle. These results are compared with a traditional computer aided design based approach.

Program for refan JT8D engine design, fabrication and test, phase 2

NASA Technical Reports Server (NTRS)

Glass, J. A.; Zimmerman, E. S.; Scaramella, V. M.

1975-01-01

The objective of the JT8D refan program was to design, fabricate, and test certifiable modifications of the JT8D engine which would reduce noise generated by JT8D powered aircraft. This was to be accomplished without affecting reliability and maintainability, at minimum retrofit cost, and with no performance penalty. The mechanical design, engine performance and stability characteristics at sea-level and altitude, and the engine noise characteristics of the test engines are documented. Results confirmed the structural integrity of the JT8D-109. Engine operation was stable throughout the airplane flight envelope. Fuel consumption of the test engines was higher than that required to meet the goal of no airplane performance penalty, but the causes were identified and corrected during a normal pre-certification engine development program. Compared to the baseline JT8D-109 engine, the acoustically treated JT8D-109 engine showed noise reductions of 6 PNdB at takeoff and 11 PNdB at a typical approach power setting.

Computer Program Re-layers Engineering Drawings

NASA Technical Reports Server (NTRS)

Crosby, Dewey C., III

1990-01-01

RULCHK computer program aids in structuring layers of information pertaining to part or assembly designed with software described in article "Software for Drawing Design Details Concurrently" (MFS-28444). Checks and optionally updates structure of layers for part. Enables designer to construct model and annotate its documentation without burden of manually layering part to conform to standards at design time.

Joint US/Russia TU-144 Engine Ground Tests

NASA Technical Reports Server (NTRS)

Acosta, Waldo A.; Balser, Jeffrey S.; McCartney, Timothy P.; Richter, Charles A.; Woike, Mark R.

1997-01-01

Two engine research experiments were recently completed in Moscow, Russia using an engine from the Tu-144 supersonic transport airplane. This was a joint project between the United States and Russia. Personnel from the NASA Lewis Research Center, General Electric Aircraft Engines, Pratt & Whitney, the Tupolev Design Bureau, and EBP Aircraft LTD worked together as a team to overcome the many technical and cultural challenges. The objective was to obtain large scale inlet data that could be used in the development of a supersonic inlet system for a future High Speed Civil Transport (HSCT). The-first experiment studied the impact of typical inlet structures that have trailing edges in close proximity to the inlet/engine interface plane on the flow characteristics at that plane. The inlet structure simulated the subsonic diffuser of a supersonic inlet using a bifurcated splitter design. The centerbody maximum diameter was designed to permit choking and slightly supercritical operation. The second experiment measured the reflective characteristics of the engine face to incoming perturbations of pressure amplitude. The basic test rig from the first experiment was used with a longer spacer equipped with fast actuated doors. All the objectives set forth at the beginning of the project were met.

Thermal/structural Tailoring of Engine Blades (T/SEAEBL). Theoretical Manual

NASA Technical Reports Server (NTRS)

Brown, K. W.; Clevenger, W. B.

1994-01-01

The Thermal/Structural Tailoring of Engine Blades (T/STAEBL) system is a family of computer programs executed by a control program. The T/STAEBL system performs design optimizations of cooled, hollow turbine blades and vanes. This manual describes the T/STAEBL data block structure and system organization. The approximate analysis and optimization modules are detailed, and a validation test case is provided.

Thermal/structural tailoring of engine blades (T/SEAEBL). Theoretical manual

NASA Astrophysics Data System (ADS)

Brown, K. W.; Clevenger, W. B.

1994-03-01

The Thermal/Structural Tailoring of Engine Blades (T/STAEBL) system is a family of computer programs executed by a control program. The T/STAEBL system performs design optimizations of cooled, hollow turbine blades and vanes. This manual describes the T/STAEBL data block structure and system organization. The approximate analysis and optimization modules are detailed, and a validation test case is provided.

Beyond directed evolution - semi-rational protein engineering and design

PubMed Central

Lutz, Stefan

2010-01-01

Over the last two decades, directed evolution has transformed the field of protein engineering. The advances in understanding protein structure and function, in no insignificant part a result of directed evolution studies, are increasingly empowering scientists and engineers to device more effective methods for manipulating and tailoring biocatalysts. Abandoning large combinatorial libraries, the focus has shifted to small, functionally-rich libraries and rational design. A critical component to the success of these emerging engineering strategies are computational tools for the evaluation of protein sequence datasets and the analysis of conformational variations of amino acids in proteins. Highlighting the opportunities and limitations of such approaches, this review focuses on recent engineering and design examples that require screening or selection of small libraries. PMID:20869867

Segmented molecular design of self-healing proteinaceous materials

PubMed Central

Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C.

2015-01-01

Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure–property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials. PMID:26323335

Mechanical Engineering at KSC: 'How I spend My Hours from 9 to 5 and Draw a Paycheck'

NASA Technical Reports Server (NTRS)

Randazzo, John; Steinrock. Todd (Technical Monitor)

2003-01-01

This viewgraph presentation provides an overview of a senior mechanical engineer's role in designing and testing sensors to fly aboard the shuttle Discovery during STS-95 and STS-98. Topics covered include: software development tools, computation fluid dynamics, structural analysis, housing design, and systems integration.

NASA Engineering Design Challenges: Spacecraft Structures. EP-2008-09-121-MSFC

ERIC Educational Resources Information Center

Haddad, Nick; McWilliams, Harold; Wagoner, Paul

2007-01-01

NASA (National Aeronautics and Space Administration) Engineers at Marshall Space Flight Center along with their partners at other NASA centers, and in private industry, are designing and beginning to develop the next generation of spacecraft to transport cargo, equipment, and human explorers to space. These vehicles are part of the Constellation…

Empirical relationship between electrical resistivity and geotechnical parameters: A case study of Federal University of Technology campus, Akure SW, Nigeria

NASA Astrophysics Data System (ADS)

Akintorinwa, O. J.; Oluwole, S. T.

2018-06-01

For several decades, geophysical prospecting method coupled with geotechnical analysis has become increasingly useful in evaluating the subsurface for both pre and post engineering investigations. Shallow geophysical tool is often used alongside geotechnical method to evaluate subsurface soil for engineering study to obtain information which may include the subsurface lithology and their thicknesses, competence of the bedrock and depths to its upper interface, and competence of the material that make up the overburden, especially the shallow section which serves as host for foundations of engineering structures (Aina et al., 1996; Adewumi and Olorunfemi, 2005; and Idornigie et al., 2006). This information helps the engineers to correctly locate and design the foundation of engineering structures. The information also serves as guide to the choice of design and suitable materials needed for road construction (Akinlabi and Adeyemi, 2014). Lack of knowledge of the properties of subsurface may leads to the failure of most engineering structures. Therefore, it is of great importance to carry out a pre-construction investigation of a proposed site in order to ascertain the fitness of the host earth material.

APPLICATION OF THE 3D MODEL OF RAILWAY VIADUCTS TO COST ESTIMATION AND CONSTRUCTION

NASA Astrophysics Data System (ADS)

Fujisawa, Yasuo; Yabuki, Nobuyoshi; Igarashi, Zenichi; Yoshino, Hiroyuki

Three dimensional models of civil engineering structures are only partially used in either design or construction but not both. Research on integration of design, cost estimation and construction by 3Dmodels has not been heard in civil engineering domain yet. Using continuously a 3D product model of a structure from design to construction through estimation should improve the efficiency and decrease the occurrence of mistakes, hence enhancing the quality. In this research, we investigated the current practices of flow from design to construction, particularly focusing on cost estimation. Then, we identified advantages and issues on utilization of 3D design models to estimation and construction by applying 3D models to an actual railway construction project.

Liquid rocket engine nozzles

NASA Technical Reports Server (NTRS)

1976-01-01

The nozzle is a major component of a rocket engine, having a significant influence on the overall engine performance and representing a large fraction of the engine structure. The design of the nozzle consists of solving simultaneously two different problems: the definition of the shape of the wall that forms the expansion surface, and the delineation of the nozzle structure and hydraulic system. This monography addresses both of these problems. The shape of the wall is considered from immediately upstream of the throat to the nozzle exit for both bell and annular (or plug) nozzles. Important aspects of the methods used to generate nozzle wall shapes are covered for maximum-performance shapes and for nozzle contours based on criteria other than performance. The discussion of structure and hydraulics covers problem areas of regeneratively cooled tube-wall nozzles and extensions; it treats also nozzle extensions cooled by turbine exhaust gas, ablation-cooled extensions, and radiation-cooled extensions. The techniques that best enable the designer to develop the nozzle structure with as little difficulty as possible and at the lowest cost consistent with minimum weight and specified performance are described.

SSME lifetime prediction and verification, integrating environments, structures, materials: The challenge

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Salter, L. D.; Young, G. M., III; Munafo, P. M.

1985-01-01

The planned missions for the space shuttle dictated a unique and technology-extending rocket engine. The high specific impulse requirements in conjunction with a 55-mission lifetime, plus volume and weight constraints, produced unique structural design, manufacturing, and verification requirements. Operations from Earth to orbit produce severe dynamic environments, which couple with the extreme pressure and thermal environments associated with the high performance, creating large low cycle loads and high alternating stresses above endurance limit which result in high sensitivity to alternating stresses. Combining all of these effects resulted in the requirements for exotic materials, which are more susceptible to manufacturing problems, and the use of an all-welded structure. The challenge of integrating environments, dynamics, structures, and materials into a verified SSME structure is discussed. The verification program and developmental flight results are included. The first six shuttle flights had engine performance as predicted with no failures. The engine system has met the basic design challenges.

Quiet Clean Short-haul Experimental Engine (QCSEE) preliminary under the wing flight propulsion system analysis report

NASA Technical Reports Server (NTRS)

Howard, D. F.

1976-01-01

The preliminary design and installation of high bypass, geared turbofan engine with a composite nacelle forming the propulsion system for a short haul passenger aircraft are described. The technology required for externally blown flap aircraft with under the wing (UTW) propulsion system installations for introduction into passenger service in the mid 1980's is included. The design, fabrication, and testing of this UTW experimental engine containing the required technology items for low noise, fuel economy, with composite structure for reduced weight and digital engine control are provided.

Decoupling local mechanics from large-scale structure in modular metamaterials.

PubMed

Yang, Nan; Silverberg, Jesse L

2017-04-04

A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such "inverse design" is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module's design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.

Performance-based seismic design of nonstructural building components: The next frontier of earthquake engineering

NASA Astrophysics Data System (ADS)

Filiatrault, Andre; Sullivan, Timothy

2014-08-01

With the development and implementation of performance-based earthquake engineering, harmonization of performance levels between structural and nonstructural components becomes vital. Even if the structural components of a building achieve a continuous or immediate occupancy performance level after a seismic event, failure of architectural, mechanical or electrical components can lower the performance level of the entire building system. This reduction in performance caused by the vulnerability of nonstructural components has been observed during recent earthquakes worldwide. Moreover, nonstructural damage has limited the functionality of critical facilities, such as hospitals, following major seismic events. The investment in nonstructural components and building contents is far greater than that of structural components and framing. Therefore, it is not surprising that in many past earthquakes, losses from damage to nonstructural components have exceeded losses from structural damage. Furthermore, the failure of nonstructural components can become a safety hazard or can hamper the safe movement of occupants evacuating buildings, or of rescue workers entering buildings. In comparison to structural components and systems, there is relatively limited information on the seismic design of nonstructural components. Basic research work in this area has been sparse, and the available codes and guidelines are usually, for the most part, based on past experiences, engineering judgment and intuition, rather than on objective experimental and analytical results. Often, design engineers are forced to start almost from square one after each earthquake event: to observe what went wrong and to try to prevent repetitions. This is a consequence of the empirical nature of current seismic regulations and guidelines for nonstructural components. This review paper summarizes current knowledge on the seismic design and analysis of nonstructural building components, identifying major knowledge gaps that will need to be filled by future research. Furthermore, considering recent trends in earthquake engineering, the paper explores how performance-based seismic design might be conceived for nonstructural components, drawing on recent developments made in the field of seismic design and hinting at the specific considerations required for nonstructural components.

CCARES: A computer algorithm for the reliability analysis of laminated CMC components

NASA Technical Reports Server (NTRS)

Duffy, Stephen F.; Gyekenyesi, John P.

1993-01-01

Structural components produced from laminated CMC (ceramic matrix composite) materials are being considered for a broad range of aerospace applications that include various structural components for the national aerospace plane, the space shuttle main engine, and advanced gas turbines. Specifically, these applications include segmented engine liners, small missile engine turbine rotors, and exhaust nozzles. Use of these materials allows for improvements in fuel efficiency due to increased engine temperatures and pressures, which in turn generate more power and thrust. Furthermore, this class of materials offers significant potential for raising the thrust-to-weight ratio of gas turbine engines by tailoring directions of high specific reliability. The emerging composite systems, particularly those with silicon nitride or silicon carbide matrix, can compete with metals in many demanding applications. Laminated CMC prototypes have already demonstrated functional capabilities at temperatures approaching 1400 C, which is well beyond the operational limits of most metallic materials. Laminated CMC material systems have several mechanical characteristics which must be carefully considered in the design process. Test bed software programs are needed that incorporate stochastic design concepts that are user friendly, computationally efficient, and have flexible architectures that readily incorporate changes in design philosophy. The CCARES (Composite Ceramics Analysis and Reliability Evaluation of Structures) program is representative of an effort to fill this need. CCARES is a public domain computer algorithm, coupled to a general purpose finite element program, which predicts the fast fracture reliability of a structural component under multiaxial loading conditions.

Load Testing, Finite Element Analysis, and Design of Steel Traffic-Signal Poles

DOT National Transportation Integrated Search

1993-07-01

At request of the Structures Design and Construction Division, the Engineering Research and Development Bureau performed full-scale testing and finite element analysis (FEA) of span-wire traffic-signal poles to evaluate their structural adequacy. Res...

Exploring the repeat protein universe through computational protein design

DOE PAGES

Brunette, TJ; Parmeggiani, Fabio; Huang, Po-Ssu; ...

2015-12-16

A central question in protein evolution is the extent to which naturally occurring proteins sample the space of folded structures accessible to the polypeptide chain. Repeat proteins composed of multiple tandem copies of a modular structure unit are widespread in nature and have critical roles in molecular recognition, signalling, and other essential biological processes. Naturally occurring repeat proteins have been re-engineered for molecular recognition and modular scaffolding applications. In this paper, we use computational protein design to investigate the space of folded structures that can be generated by tandem repeating a simple helix–loop–helix–loop structural motif. Eighty-three designs with sequences unrelatedmore » to known repeat proteins were experimentally characterized. Of these, 53 are monomeric and stable at 95 °C, and 43 have solution X-ray scattering spectra consistent with the design models. Crystal structures of 15 designs spanning a broad range of curvatures are in close agreement with the design models with root mean square deviations ranging from 0.7 to 2.5 Å. Finally, our results show that existing repeat proteins occupy only a small fraction of the possible repeat protein sequence and structure space and that it is possible to design novel repeat proteins with precisely specified geometries, opening up a wide array of new possibilities for biomolecular engineering.« less

Structural topology optimization with fuzzy constraint

NASA Astrophysics Data System (ADS)

Rosko, Peter

2011-12-01

The paper deals with the structural topology optimization with fuzzy constraint. The optimal topology of structure is defined as a material distribution problem. The objective is the weight of the structure. The multifrequency dynamic loading is considered. The optimal topology design of the structure has to eliminate the danger of the resonance vibration. The uncertainty of the loading is defined with help of fuzzy loading. Special fuzzy constraint is created from exciting frequencies. Presented study is applicable in engineering and civil engineering. Example demonstrates the presented theory.

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1993-01-01

The Advanced Turbine Technologies Application Project (ATTAP) is in the fifth year of a multiyear development program to bring the automotive gas turbine engine to a state at which industry can make commercialization decisions. Activities during the past year included reference powertrain design updates, test-bed engine design and development, ceramic component design, materials and component characterization, ceramic component process development and fabrication, ceramic component rig testing, and test-bed engine fabrication and testing. Engine design and development included mechanical design, combustion system development, alternate aerodynamic flow testing, and controls development. Design activities included development of the ceramic gasifier turbine static structure, the ceramic gasifier rotor, and the ceramic power turbine rotor. Material characterization efforts included the testing and evaluation of five candidate high temperature ceramic materials. Ceramic component process development and fabrication, with the objective of approaching automotive volumes and costs, continued for the gasifier turbine rotor, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Engine and rig fabrication, testing, and development supported improvements in ceramic component technology. Total test time in 1992 amounted to 599 hours, of which 147 hours were engine testing and 452 were hot rig testing.

An investigation of constraint-based component-modeling for knowledge representation in computer-aided conceptual design

NASA Technical Reports Server (NTRS)

Kolb, Mark A.

1990-01-01

Originally, computer programs for engineering design focused on detailed geometric design. Later, computer programs for algorithmically performing the preliminary design of specific well-defined classes of objects became commonplace. However, due to the need for extreme flexibility, it appears unlikely that conventional programming techniques will prove fruitful in developing computer aids for engineering conceptual design. The use of symbolic processing techniques, such as object-oriented programming and constraint propagation, facilitate such flexibility. Object-oriented programming allows programs to be organized around the objects and behavior to be simulated, rather than around fixed sequences of function- and subroutine-calls. Constraint propagation allows declarative statements to be understood as designating multi-directional mathematical relationships among all the variables of an equation, rather than as unidirectional assignments to the variable on the left-hand side of the equation, as in conventional computer programs. The research has concentrated on applying these two techniques to the development of a general-purpose computer aid for engineering conceptual design. Object-oriented programming techniques are utilized to implement a user-extensible database of design components. The mathematical relationships which model both geometry and physics of these components are managed via constraint propagation. In addition, to this component-based hierarchy, special-purpose data structures are provided for describing component interactions and supporting state-dependent parameters. In order to investigate the utility of this approach, a number of sample design problems from the field of aerospace engineering were implemented using the prototype design tool, Rubber Airplane. The additional level of organizational structure obtained by representing design knowledge in terms of components is observed to provide greater convenience to the program user, and to result in a database of engineering information which is easier both to maintain and to extend.

An overview of reliability assessment and control for design of civil engineering structures

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

Field, R.V. Jr.; Grigoriadis, K.M.; Bergman, L.A.

1998-06-01

Random variations, whether they occur in the input signal or the system parameters, are phenomena that occur in nearly all engineering systems of interest. As a result, nondeterministic modeling techniques must somehow account for these variations to ensure validity of the solution. As might be expected, this is a difficult proposition and the focus of many current research efforts. Controlling seismically excited structures is one pertinent application of nondeterministic analysis and is the subject of the work presented herein. This overview paper is organized into two sections. First, techniques to assess system reliability, in a context familiar to civil engineers,more » are discussed. Second, and as a consequence of the first, active control methods that ensure good performance in this random environment are presented. It is the hope of the authors that these discussions will ignite further interest in the area of reliability assessment and design of controlled civil engineering structures.« less

Cabin-fuselage-wing structural design concept with engine installation

NASA Technical Reports Server (NTRS)

Ariotti, Scott; Garner, M.; Cepeda, A.; Vieira, J.; Bolton, D.

1993-01-01

The purpose of this project is to provide a fuselage structural assembly and wing structural design that will be able to withstand the given operational parameters and loads provided by Federal Aviation Regulation Part 23 (FAR 23) and the Statement of Work (SOW). The goal is to provide a durable lightweight structure that will transfer the applied loads through the most efficient load path. Areas of producibility and maintainability of the structure will also be addressed. All of the structural members will also meet or exceed the desired loading criteria, along with providing adequate stiffness, reliability, and fatigue life as stated in the SOW. Considerations need to be made for control system routing and cabin heating/ventilation. The goal of the wing structure and carry through structure is also to provide a simple, lightweight structure that will transfer the aerodynamic forces produced by the wing, tailboom, and landing gear. These forces will be channeled through various internal structures sized for the pre-determined loading criteria. Other considerations were to include space for flaps, ailerons, fuel tanks, and electrical and control system routing. The difficulties encountered in the fuselage design include expanding the fuselage cabin to accept a third occupant in a staggered configuration and providing ample volume for their safety. By adding a third person the CG of aircraft will move forward so the engine needs to be moved aft to compensate for the difference in the moment. This required the provisions of a ring frame structure for the new position of the engine mount. The difficulties encountered in the wing structural design include resizing the wing for the increased capacity and weight, and compensating for a large torsion produced by the tail boom by placing a great number of stiffeners inside the boom, which will result in the relocation of the fuel tank. Finally, an adequate carry through structure for the wing and fuselage interface will be designed to effectively transmit loads through the fuselage.

Project CAD as of July 1978: CAD support project, situation in July 1978

NASA Technical Reports Server (NTRS)

Boesch, L.; Lang-Lendorff, G.; Rothenberg, R.; Stelzer, V.

1979-01-01

The structure of Computer Aided Design (CAD) and the requirements for program developments in past and future are described. The actual standard and the future aims of CAD programs are presented. The developed programs in: (1) civil engineering; (2) mechanical engineering; (3) chemical engineering/shipbuilding; (4) electrical engineering; and (5) general programs are discussed.

Structural integrity and containment aspects of small gas turbine engines

NASA Astrophysics Data System (ADS)

Gupta, S. S.; Gomuc, R.

1994-03-01

Structural integrity of rotating components in gas turbine engines is very crucial since their failure implies high impact energy, which, if uncontained, could mean damage to aircraft structures, controls, and so forth, and, in the worst scenario, even loss of lives. This final consequence has led to very stringent airworthiness regulations for engine/aircraft certifications. This paper discusses the historical statistics of noncontainment events in turbofans, turboprops, and turboshafts and shows how the damage severity varies between different applications and how changes to regulations are continuing in order to improve the reliability of aircraft/rotorcraft. The paper also presents design challenges resulting from the analysis complexity of containment/noncontainment event and the way Pratt & Whitney Canada design/analysis/test system caters to all the requirements. The weight and cost impact of possible changes to current regulations are also presented.

An efficient constraint to account for mistuning effects in the optimal design of engine rotors

NASA Technical Reports Server (NTRS)

Murthy, Durbha V.; Pierre, Christophe; Ottarsson, Gisli

1992-01-01

Blade-to-blade differences in structural properties, unavoidable in practice due to manufacturing tolerances, can have significant influence on the vibratory response of engine rotor blade. Accounting for these differences, also known as mistuning, in design and in optimization procedures is generally not possible. This note presents an easily calculated constraint that can be used in design and optimization procedures to control the sensitivity of final designs to mistuning.

44 CFR 65.10 - Mapping of areas protected by levee systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... requirement described in paragraph (b)(1)(i) of this section, may be approved. Appropriate engineering... paragraph (b)(1)(iii) of this section, may be approved. Appropriate engineering analyses demonstrating... are structural parts of the system during operation and design according to sound engineering practice...

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

Turning up the heat on aircraft structures. [design and analysis for high-temperature conditions

NASA Technical Reports Server (NTRS)

Dobyns, Alan; Saff, Charles; Johns, Robert

1992-01-01

An overview is presented of the current effort in design and development of aircraft structures to achieve the lowest cost for best performance. Enhancements in this area are focused on integrated design, improved design analysis tools, low-cost fabrication techniques, and more sophisticated test methods. 3D CAD/CAM data are becoming the method through which design, manufacturing, and engineering communicate.

Spatial Cognition Support for Exploring the Design Mechanics of Building Structures

ERIC Educational Resources Information Center

Rudy, Margit; Hauck, Richard

2008-01-01

A web-based tool for visualizing the simulated structural behavior of building models was developed to support the teaching of structural design to architecture and engineering students by activating their spatial cognition capabilities. The main didactic issues involved establishing a consistent and complete three-dimensional vocabulary (3D)…

Program user's manual for optimizing the design of a liquid or gaseous propellant rocket engine with the automated combustor design code AUTOCOM

NASA Technical Reports Server (NTRS)

Reichel, R. H.; Hague, D. S.; Jones, R. T.; Glatt, C. R.

1973-01-01

This computer program manual describes in two parts the automated combustor design optimization code AUTOCOM. The program code is written in the FORTRAN 4 language. The input data setup and the program outputs are described, and a sample engine case is discussed. The program structure and programming techniques are also described, along with AUTOCOM program analysis.

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1994-01-01

Reports technical effort by AlliedSignal Engines in sixth year of DOE/NASA funded project. Topics include: gas turbine engine design modifications of production APU to incorporate ceramic components; fabrication and processing of silicon nitride blades and nozzles; component and engine testing; and refinement and development of critical ceramics technologies, including: hot corrosion testing and environmental life predictive model; advanced NDE methods for internal flaws in ceramic components; and improved carbon pulverization modeling during impact. ATTAP project is oriented toward developing high-risk technology of ceramic structural component design and fabrication to carry forward to commercial production by 'bridging the gap' between structural ceramics in the laboratory and near-term commercial heat engine application. Current ATTAP project goal is to support accelerated commercialization of advanced, high-temperature engines for hybrid vehicles and other applications. Project objectives are to provide essential and substantial early field experience demonstrating ceramic component reliability and durability in modified, available, gas turbine engine applications; and to scale-up and improve manufacturing processes of ceramic turbine engine components and demonstrate application of these processes in the production environment.

Knowledge, attitude and practices for design for safety: A study on civil & structural engineers.

PubMed

Goh, Yang Miang; Chua, Sijie

2016-08-01

Design for safety (DfS) (also known as prevention through design, safe design and Construction (Design and Management)) promotes early consideration of safety and health hazards during the design phase of a construction project. With early intervention, hazards can be more effectively eliminated or controlled leading to safer worksites and construction processes. DfS is practiced in many countries, including Australia, the UK, and Singapore. In Singapore, the Manpower Ministry enacted the DfS Regulations in July 2015, which will be enforced from August 2016 onwards. Due to the critical role of civil and structural (C&S) engineers during design and construction, the DfS knowledge, attitude and practices (KAP) of C&S engineers have significant impact on the successful implementation of DfS. Thus, this study aims to explore the DfS KAP of C&S engineers so as to guide further research in measuring and improving DfS KAP of designers. During the study, it was found that there is a lack of KAP studies in construction management. Therefore, this study also aims to provide useful lessons for future applications of the KAP framework in construction management research. A questionnaire was developed to assess the DfS KAP of C&S engineers. The responses provided by 43 C&S engineers were analyzed. In addition, interviews with experienced construction professionals were carried out to further understand perceptions of DfS and related issues. The results suggest that C&S engineers are supportive of DfS, but the level of DfS knowledge and practices need to be improved. More DfS guidelines and training should be made available to the engineers. To ensure that DfS can be implemented successfully, there is a need to study the contractual arrangements between clients and designers and the effectiveness of different implementation approaches for the DfS process. The questionnaire and findings in this study provided the foundation for a baseline survey with larger sample size, which is currently being planned. In contrast to earlier studies, the study showed that the responding C&S engineers were supportive of the DfS. The study showed that the key to improving the DfS KAP of C&S engineers is by improving clients' motivation for DfS. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computer-Aided Structural Engineering (CASE) Project: Investigation and Design of U-Frame Structures Using Program CUFRBC. Volume C. User’s Guide for Channels

DTIC Science & Technology

1990-05-01

1988) or ACI 318-83 (1983). Actual calculations for section strength are made using subroutines taken from the CASE program CSTR (Hamby and Price...validity of the design of their par- ticular structure. Thus, it is essential that the user of the program under- stand the design algorithm included...modes. However, several restrictions were placed on the design mode to avoid unnecessary com- plications of the design algorithm for cases rarely

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5

PubMed Central

Azoitei, M.L.; Ban, Y.A.; Kalyuzhny, O.; Guenaga, J.; Schroeter, A.; Porter, J.; Wyatt, R.; Schief, W.R.

2015-01-01

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of pre-defined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of HIV-1 neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with sub-nanomolar affinity (KD = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity. PMID:25043744

48 CFR 52.236-25 - Requirements for Registration of Designers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... engineers registered to practice in the particular professional field involved in a State, the District of... architectural, structural, mechanical, electrical, civil, or other engineering features of the work. (End of...

48 CFR 52.236-25 - Requirements for Registration of Designers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... engineers registered to practice in the particular professional field involved in a State, the District of... architectural, structural, mechanical, electrical, civil, or other engineering features of the work. (End of...

48 CFR 52.236-25 - Requirements for Registration of Designers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... engineers registered to practice in the particular professional field involved in a State, the District of... architectural, structural, mechanical, electrical, civil, or other engineering features of the work. (End of...

48 CFR 52.236-25 - Requirements for Registration of Designers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... engineers registered to practice in the particular professional field involved in a State, the District of... architectural, structural, mechanical, electrical, civil, or other engineering features of the work. (End of...

48 CFR 52.236-25 - Requirements for Registration of Designers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... engineers registered to practice in the particular professional field involved in a State, the District of... architectural, structural, mechanical, electrical, civil, or other engineering features of the work. (End of...

Research and development activities in unified control-structure modeling and design

NASA Technical Reports Server (NTRS)

Nayak, A. P.

1985-01-01

Results of work to develop a unified control/structures modeling and design capability for large space structures modeling are presented. Recent analytical results are presented to demonstrate the significant interdependence between structural and control properties. A new design methodology is suggested in which the structure, material properties, dynamic model and control design are all optimized simultaneously. Parallel research done by other researchers is reviewed. The development of a methodology for global design optimization is recommended as a long-term goal. It is suggested that this methodology should be incorporated into computer aided engineering programs, which eventually will be supplemented by an expert system to aid design optimization.

Using CASE tools to write engineering specifications

NASA Astrophysics Data System (ADS)

Henry, James E.; Howard, Robert W.; Iveland, Scott T.

1993-08-01

There are always a wide variety of obstacles to writing and maintaining engineering documentation. To combat these problems, documentation generation can be linked to the process of engineering development. The same graphics and communication tools used for structured system analysis and design (SSA/SSD) also form the basis for the documentation. The goal is to build a living document, such that as an engineering design changes, the documentation will `automatically' revise. `Automatic' is qualified by the need to maintain textual descriptions associated with the SSA/SSD graphics, and the need to generate new documents. This paper describes a methodology and a computer aided system engineering toolset that enables a relatively seamless transition into document generation for the development engineering team.

Design Approaches to Myocardial and Vascular Tissue Engineering.

PubMed

Akintewe, Olukemi O; Roberts, Erin G; Rim, Nae-Gyune; Ferguson, Michael A H; Wong, Joyce Y

2017-06-21

Engineered tissues represent an increasingly promising therapeutic approach for correcting structural defects and promoting tissue regeneration in cardiovascular diseases. One of the challenges associated with this approach has been the necessity for the replacement tissue to promote sufficient vascularization to maintain functionality after implantation. This review highlights a number of promising prevascularization design approaches for introducing vasculature into engineered tissues. Although we focus on encouraging blood vessel formation within myocardial implants, we also discuss techniques developed for other tissues that could eventually become relevant to engineered cardiac tissues. Because the ultimate solution to engineered tissue vascularization will require collaboration between wide-ranging disciplines such as developmental biology, tissue engineering, and computational modeling, we explore contributions from each field.

Structural Testing at the NWTC Helps Improve Blade Design and Increase System Reliability; NREL (National Renewable Energy Laboratory)

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

None

2015-08-01

Since 1990, the National Renewable Energy Laboratory’s (NREL's) National Wind Technology Center (NWTC) has tested more than 150 wind turbine blades. NWTC researchers can test full-scale and subcomponent articles, conduct data analyses, and provide engineering expertise on best design practices. Structural testing of wind turbine blades enables designers, manufacturers, and owners to validate designs and assess structural performance to specific load conditions. Rigorous structural testing can reveal design and manufacturing problems at an early stage of development that can lead to overall improvements in design and increase system reliability.

Towards Improved Considerations of Risk in Seismic Design (Plinius Medal Lecture)

NASA Astrophysics Data System (ADS)

Sullivan, T. J.

2012-04-01

The aftermath of recent earthquakes is a reminder that seismic risk is a very relevant issue for our communities. Implicit within the seismic design standards currently in place around the world is that minimum acceptable levels of seismic risk will be ensured through design in accordance with the codes. All the same, none of the design standards specify what the minimum acceptable level of seismic risk actually is. Instead, a series of deterministic limit states are set which engineers then demonstrate are satisfied for their structure, typically through the use of elastic dynamic analyses adjusted to account for non-linear response using a set of empirical correction factors. From the early nineties the seismic engineering community has begun to recognise numerous fundamental shortcomings with such seismic design procedures in modern codes. Deficiencies include the use of elastic dynamic analysis for the prediction of inelastic force distributions, the assignment of uniform behaviour factors for structural typologies irrespective of the structural proportions and expected deformation demands, and the assumption that hysteretic properties of a structure do not affect the seismic displacement demands, amongst other things. In light of this a number of possibilities have emerged for improved control of risk through seismic design, with several innovative displacement-based seismic design methods now well developed. For a specific seismic design intensity, such methods provide a more rational means of controlling the response of a structure to satisfy performance limit states. While the development of such methodologies does mark a significant step forward for the control of seismic risk, they do not, on their own, identify the seismic risk of a newly designed structure. In the U.S. a rather elaborate performance-based earthquake engineering (PBEE) framework is under development, with the aim of providing seismic loss estimates for new buildings. The PBEE framework consists of the following four main analysis stages: (i) probabilistic seismic hazard analysis to give the mean occurrence rate of earthquake events having an intensity greater than a threshold value, (ii) structural analysis to estimate the global structural response, given a certain value of seismic intensity, (iii) damage analysis, in which fragility functions are used to express the probability that a building component exceeds a damage state, as a function of the global structural response, (iv) loss analysis, in which the overall performance is assessed based on the damage state of all components. This final step gives estimates of the mean annual frequency with which various repair cost levels (or other decision variables) are exceeded. The realisation of this framework does suggest that risk-based seismic design is now possible. However, comparing current code approaches with the proposed PBEE framework, it becomes apparent that mainstream consulting engineers would have to go through a massive learning curve in order to apply the new procedures in practice. With this in mind, it is proposed that simplified loss-based seismic design procedures are a logical means of helping the engineering profession transition from what are largely deterministic seismic design procedures in current codes, to more rational risk-based seismic design methodologies. Examples are provided to illustrate the likely benefits of adopting loss-based seismic design approaches in practice.

Building Models to Better Understand the Importance of Cost versus Safety in Engineering

ERIC Educational Resources Information Center

Sumrall, William; Mott, Michael

2010-01-01

While some disasters involving engineered structures are due to events in nature (e.g., tornadoes, hurricanes, earthquakes), others may be caused by inadequate materials, design flaws, and poor maintenance. These catastrophes result in the loss of human lives and cost billions of dollars. In the set of lessons described here, students design a…

Nonlinear Shaping Architecture Designed with Using Evolutionary Structural Optimization Tools

NASA Astrophysics Data System (ADS)

Januszkiewicz, Krystyna; Banachowicz, Marta

2017-10-01

The paper explores the possibilities of using Structural Optimization Tools (ESO) digital tools in an integrated structural and architectural design in response to the current needs geared towards sustainability, combining ecological and economic efficiency. The first part of the paper defines the Evolutionary Structural Optimization tools, which were developed specifically for engineering purposes using finite element analysis as a framework. The development of ESO has led to several incarnations, which are all briefly discussed (Additive ESO, Bi-directional ESO, Extended ESO). The second part presents result of using these tools in structural and architectural design. Actual building projects which involve optimization as a part of the original design process will be presented (Crematorium in Kakamigahara Gifu, Japan, 2006 SANAA“s Learning Centre, EPFL in Lausanne, Switzerland 2008 among others). The conclusion emphasizes that the structural engineering and architectural design mean directing attention to the solutions which are used by Nature, designing works optimally shaped and forming their own environments. Architectural forms never constitute the optimum shape derived through a form-finding process driven only by structural optimization, but rather embody and integrate a multitude of parameters. It might be assumed that there is a similarity between these processes in nature and the presented design methods. Contemporary digital methods make the simulation of such processes possible, and thus enable us to refer back to the empirical methods of previous generations.

GRASP/Ada (Graphical Representations of Algorithms, Structures, and Processes for Ada): The development of a program analysis environment for Ada. Reverse engineering tools for Ada, task 1, phase 2

NASA Technical Reports Server (NTRS)

Cross, James H., II

1990-01-01

The study, formulation, and generation of structures for Ada (GRASP/Ada) are discussed in this second phase report of a three phase effort. Various graphical representations that can be extracted or generated from source code are described and categorized with focus on reverse engineering. The overall goal is to provide the foundation for a CASE (computer-aided software design) environment in which reverse engineering and forward engineering (development) are tightly coupled. Emphasis is on a subset of architectural diagrams that can be generated automatically from source code with the control structure diagram (CSD) included for completeness.

Decoupling local mechanics from large-scale structure in modular metamaterials

NASA Astrophysics Data System (ADS)

Yang, Nan; Silverberg, Jesse L.

2017-04-01

A defining feature of mechanical metamaterials is that their properties are determined by the organization of internal structure instead of the raw fabrication materials. This shift of attention to engineering internal degrees of freedom has coaxed relatively simple materials into exhibiting a wide range of remarkable mechanical properties. For practical applications to be realized, however, this nascent understanding of metamaterial design must be translated into a capacity for engineering large-scale structures with prescribed mechanical functionality. Thus, the challenge is to systematically map desired functionality of large-scale structures backward into a design scheme while using finite parameter domains. Such “inverse design” is often complicated by the deep coupling between large-scale structure and local mechanical function, which limits the available design space. Here, we introduce a design strategy for constructing 1D, 2D, and 3D mechanical metamaterials inspired by modular origami and kirigami. Our approach is to assemble a number of modules into a voxelized large-scale structure, where the module’s design has a greater number of mechanical design parameters than the number of constraints imposed by bulk assembly. This inequality allows each voxel in the bulk structure to be uniquely assigned mechanical properties independent from its ability to connect and deform with its neighbors. In studying specific examples of large-scale metamaterial structures we show that a decoupling of global structure from local mechanical function allows for a variety of mechanically and topologically complex designs.

Teaching Continuum Mechanics in a Mechanical Engineering Program

ERIC Educational Resources Information Center

Liu, Yucheng

2011-01-01

This paper introduces a graduate course, continuum mechanics, which is designed for and taught to graduate students in a Mechanical Engineering (ME) program. The significance of continuum mechanics in engineering education is demonstrated and the course structure is described. Methods used in teaching this course such as topics, class…

Incorporating the site variability and laboratory/in-situ testing variability of soil properties in geotechnical engineering design : research project capsule : technology transfer program.

DOT National Transportation Integrated Search

2016-04-01

While structural engineering deals with mostly homogeneous manmade materials : (e.g., concrete and steel), geotechnical engineering typically involves highly varied : natural materials (e.g., soil and rock). As a result, high variance of the resistan...

A paperless course on structural engineering programming: investing in educational technology in the times of the Greek financial recession

NASA Astrophysics Data System (ADS)

Sextos, Anastasios G.

2014-01-01

This paper presents the structure of an undergraduate course entitled 'programming techniques and the use of specialised software in structural engineering' which is offered to the fifth (final) year students of the Civil Engineering Department of Aristotle University Thessaloniki in Greece. The aim of this course is to demonstrate the use of new information technologies in the field of structural engineering and to teach modern programming and finite element simulation techniques that the students can in turn apply in both research and everyday design of structures. The course also focuses on the physical interpretation of structural engineering problems, in a way that the students become familiar with the concept of computational tools without losing perspective from the engineering problem studied. For this purpose, a wide variety of structural engineering problems are studied in class, involving structural statics, dynamics, earthquake engineering, design of reinforced concrete and steel structures as well as data and information management. The main novelty of the course is that it is taught and examined solely in the computer laboratory ensuring that each student can accomplish the prescribed 'hands-on' training on a dedicated computer, strictly on a 1:1 student over hardware ratio. Significant effort has also been put so that modern educational techniques and tools are utilised to offer the course in an essentially paperless mode. This involves electronic educational material, video tutorials, student information in real time and exams given and assessed electronically through an ad hoc developed, personalised, electronic system. The positive feedback received from the students reveals that the concept of a paperless course is not only applicable in real academic conditions but is also a promising approach that significantly increases student productivity and engagement. The question, however, is whether such an investment in educational technology is indeed timely during economic recession, where the academic priorities are rapidly changing. In the light of this unfavourable and unstable financial environment, a critical overview of the strengths, the weaknesses, the opportunities and the threats of this effort is presented herein, hopefully contributing to the discussion on the future of higher education in the time of crisis.

Computational approaches for rational design of proteins with novel functionalities

PubMed Central

Tiwari, Manish Kumar; Singh, Ranjitha; Singh, Raushan Kumar; Kim, In-Won; Lee, Jung-Kul

2012-01-01

Proteins are the most multifaceted macromolecules in living systems and have various important functions, including structural, catalytic, sensory, and regulatory functions. Rational design of enzymes is a great challenge to our understanding of protein structure and physical chemistry and has numerous potential applications. Protein design algorithms have been applied to design or engineer proteins that fold, fold faster, catalyze, catalyze faster, signal, and adopt preferred conformational states. The field of de novo protein design, although only a few decades old, is beginning to produce exciting results. Developments in this field are already having a significant impact on biotechnology and chemical biology. The application of powerful computational methods for functional protein designing has recently succeeded at engineering target activities. Here, we review recently reported de novo functional proteins that were developed using various protein design approaches, including rational design, computational optimization, and selection from combinatorial libraries, highlighting recent advances and successes. PMID:24688643

Fracture mechanics methodology: Evaluation of structural components integrity

NASA Astrophysics Data System (ADS)

Sih, G. C.; de Oliveira Faria, L.

1984-09-01

The application of fracture mechanics to structural-design problems is discussed in lectures presented in the AGARD Fracture Mechanics Methodology course held in Lisbon, Portugal, in June 1981. The emphasis is on aeronautical design, and chapters are included on fatigue-life prediction for metals and composites, the fracture mechanics of engineering structural components, failure mechanics and damage evaluation of structural components, flaw-acceptance methods, and reliability in probabilistic design. Graphs, diagrams, drawings, and photographs are provided.

30 cm Engineering Model thruster design and qualification tests

NASA Technical Reports Server (NTRS)

Schnelker, D. E.; Collett, C. R.

1975-01-01

Development of a 30-cm mercury electron bombardment Engineering Model ion thruster has successfully brought the thruster from the status of a laboratory experimental device to a point approaching flight readiness. This paper describes the development progress of the Engineering Model (EM) thruster in four areas: (1) design features and fabrication approaches, (2) performance verification and thruster to thruster variations, (3) structural integrity, and (4) interface definition. The design of major subassemblies, including the cathode-isolator-vaporizer (CIV), main isolator-vaporizer (MIV), neutralizer isolator-vaporizer (NIV), ion optical system, and discharge chamber/outer housing is discussed along with experimental results.

Averting Denver Airports on a Chip

NASA Technical Reports Server (NTRS)

Sullivan, Kevin J.

1995-01-01

As a result of recent advances in software engineering capabilities, we are now in a more stable environment. De-facto hardware and software standards are emerging. Work on software architecture and design patterns signals a consensus on the importance of early system-level design decisions, and agreements on the uses of certain paradigmatic software structures. We now routinely build systems that would have been risky or infeasible a few years ago. Unfortunately, technological developments threaten to destabilize software design again. Systems designed around novel computing and peripheral devices will spark ambitious new projects that will stress current software design and engineering capabilities. Micro-electro-mechanical systems (MEMS) and related technologies provide the physical basis for new systems with the potential to produce this kind of destabilizing effect. One important response to anticipated software engineering and design difficulties is carefully directed engineering-scientific research. Two specific problems meriting substantial research attention are: A lack of sufficient means to build software systems by generating, extending, specializing, and integrating large-scale reusable components; and a lack of adequate computational and analytic tools to extend and aid engineers in maintaining intellectual control over complex software designs.

Structural, kinetic, and thermodynamic studies of specificity designed HIV-1 protease.

PubMed

Alvizo, Oscar; Mittal, Seema; Mayo, Stephen L; Schiffer, Celia A

2012-07-01

HIV-1 protease recognizes and cleaves more than 12 different substrates leading to viral maturation. While these substrates share no conserved motif, they are specifically selected for and cleaved by protease during viral life cycle. Drug resistant mutations evolve within the protease that compromise inhibitor binding but allow the continued recognition of all these substrates. While the substrate envelope defines a general shape for substrate recognition, successfully predicting the determinants of substrate binding specificity would provide additional insights into the mechanism of altered molecular recognition in resistant proteases. We designed a variant of HIV protease with altered specificity using positive computational design methods and validated the design using X-ray crystallography and enzyme biochemistry. The engineered variant, Pr3 (A28S/D30F/G48R), was designed to preferentially bind to one out of three of HIV protease's natural substrates; RT-RH over p2-NC and CA-p2. In kinetic assays, RT-RH binding specificity for Pr3 increased threefold compared to the wild-type (WT), which was further confirmed by isothermal titration calorimetry. Crystal structures of WT protease and the designed variant in complex with RT-RH, CA-p2, and p2-NC were determined. Structural analysis of the designed complexes revealed that one of the engineered substitutions (G48R) potentially stabilized heterogeneous flap conformations, thereby facilitating alternate modes of substrate binding. Our results demonstrate that while substrate specificity could be engineered in HIV protease, the structural pliability of protease restricted the propagation of interactions as predicted. These results offer new insights into the plasticity and structural determinants of substrate binding specificity of the HIV-1 protease. Copyright © 2012 The Protein Society.

49 CFR 579.4 - Terminology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... uses to designate a discrete model of vehicle, irrespective of the calendar year in which the vehicle..., etc.), and mounting elements (such as brackets, fasteners, etc.). Platform means the basic structure... elements of the engine compartment. The term includes a structure that a manufacturer designates as a...

Design of Accelerator Online Simulator Server Using Structured Data

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

Shen, Guobao; /Brookhaven; Chu, Chungming

2012-07-06

Model based control plays an important role for a modern accelerator during beam commissioning, beam study, and even daily operation. With a realistic model, beam behaviour can be predicted and therefore effectively controlled. The approach used by most current high level application environments is to use a built-in simulation engine and feed a realistic model into that simulation engine. Instead of this traditional monolithic structure, a new approach using a client-server architecture is under development. An on-line simulator server is accessed via network accessible structured data. With this approach, a user can easily access multiple simulation codes. This paper describesmore » the design, implementation, and current status of PVData, which defines the structured data, and PVAccess, which provides network access to the structured data.« less

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.

PMR Graphite Engine Duct Development

NASA Technical Reports Server (NTRS)

Stotler, C. L.; Yokel, S. A.

1989-01-01

The objective was to demonstrate the cost and weight advantages that could be obtained by utilizing the graphite/PMR15 material system to replace titanium in selected turbofan engine applications. The first component to be selected as a basis for evaluation was the outer bypass duct of the General Electric F404 engine. The operating environment of this duct was defined and then an extensive mechanical and physical property test program was conducted using material made by processing techniques which were also established by this program. Based on these properties, design concepts to fabricate a composite version of the duct were established and two complete ducts fabricated. One of these ducts was proof pressure tested and then run successfully on a factory test engine for over 1900 hours. The second duct was static tested to 210 percent design limit load without failure. An improved design was then developed which utilized integral composite end flanges. A complete duct was fabricated and successfully proof pressure tested. The net results of this effort showed that a composite version of the outer duct would be 14 percent lighter and 30 percent less expensive that the titanium duct. The other type of structure chosen for investigation was the F404 fan stator assembly, including the fan stator vanes. It was concluded that it was feasible to utilize composite materials for this type structure but that the requirements imposed by replacing an existing metal design resulted in an inefficient composite design. It was concluded that if composites were to be effectively used in this type structure, the design must be tailored for composite application from the outset.

Inverse problems in the design, modeling and testing of engineering systems

NASA Technical Reports Server (NTRS)

Alifanov, Oleg M.

1991-01-01

Formulations, classification, areas of application, and approaches to solving different inverse problems are considered for the design of structures, modeling, and experimental data processing. Problems in the practical implementation of theoretical-experimental methods based on solving inverse problems are analyzed in order to identify mathematical models of physical processes, aid in input data preparation for design parameter optimization, help in design parameter optimization itself, and to model experiments, large-scale tests, and real tests of engineering systems.

Design criteria monograph on turbopump inducers

NASA Technical Reports Server (NTRS)

1972-01-01

State of the art and design criteria for liquid rocket engine turbopump inducers are summarized for optimal fabrication. Design criteria optimize hydrodynamic parameters to obtain highest suction specific speed without violating structural and mechanical constraints.

Building information modelling review with potential applications in tunnel engineering of China.

PubMed

Zhou, Weihong; Qin, Haiyang; Qiu, Junling; Fan, Haobo; Lai, Jinxing; Wang, Ke; Wang, Lixin

2017-08-01

Building information modelling (BIM) can be applied to tunnel engineering to address a number of problems, including complex structure, extensive design, long construction cycle and increased security risks. To promote the development of tunnel engineering in China, this paper combines actual cases, including the Xingu mountain tunnel and the Shigu Mountain tunnel, to systematically analyse BIM applications in tunnel engineering in China. The results indicate that BIM technology in tunnel engineering is currently mainly applied during the design stage rather than during construction and operation stages. The application of BIM technology in tunnel engineering covers many problems, such as a lack of standards, incompatibility of different software, disorganized management, complex combination with GIS (Geographic Information System), low utilization rate and poor awareness. In this study, through summary of related research results and engineering cases, suggestions are introduced and an outlook for the BIM application in tunnel engineering in China is presented, which provides guidance for design optimization, construction standards and later operation maintenance.

Building information modelling review with potential applications in tunnel engineering of China

PubMed Central

Zhou, Weihong; Qin, Haiyang; Fan, Haobo; Lai, Jinxing; Wang, Ke; Wang, Lixin

2017-01-01

Building information modelling (BIM) can be applied to tunnel engineering to address a number of problems, including complex structure, extensive design, long construction cycle and increased security risks. To promote the development of tunnel engineering in China, this paper combines actual cases, including the Xingu mountain tunnel and the Shigu Mountain tunnel, to systematically analyse BIM applications in tunnel engineering in China. The results indicate that BIM technology in tunnel engineering is currently mainly applied during the design stage rather than during construction and operation stages. The application of BIM technology in tunnel engineering covers many problems, such as a lack of standards, incompatibility of different software, disorganized management, complex combination with GIS (Geographic Information System), low utilization rate and poor awareness. In this study, through summary of related research results and engineering cases, suggestions are introduced and an outlook for the BIM application in tunnel engineering in China is presented, which provides guidance for design optimization, construction standards and later operation maintenance. PMID:28878970

Building information modelling review with potential applications in tunnel engineering of China

NASA Astrophysics Data System (ADS)

Zhou, Weihong; Qin, Haiyang; Qiu, Junling; Fan, Haobo; Lai, Jinxing; Wang, Ke; Wang, Lixin

2017-08-01

Building information modelling (BIM) can be applied to tunnel engineering to address a number of problems, including complex structure, extensive design, long construction cycle and increased security risks. To promote the development of tunnel engineering in China, this paper combines actual cases, including the Xingu mountain tunnel and the Shigu Mountain tunnel, to systematically analyse BIM applications in tunnel engineering in China. The results indicate that BIM technology in tunnel engineering is currently mainly applied during the design stage rather than during construction and operation stages. The application of BIM technology in tunnel engineering covers many problems, such as a lack of standards, incompatibility of different software, disorganized management, complex combination with GIS (Geographic Information System), low utilization rate and poor awareness. In this study, through summary of related research results and engineering cases, suggestions are introduced and an outlook for the BIM application in tunnel engineering in China is presented, which provides guidance for design optimization, construction standards and later operation maintenance.

Design of Life Extending Controls Using Nonlinear Parameter Optimization

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.; Holmes, Michael S.; Ray, Asok

1998-01-01

This report presents the conceptual development of a life extending control system where the objective is to achieve high performance and structural durability of the plant. A life extending controller is designed for a reusable rocket engine via damage mitigation in both the fuel and oxidizer turbines while achieving high performance for transient responses of the combustion chamber pressure and the O2/H2 mixture ratio. This design approach makes use of a combination of linear and nonlinear controller synthesis techniques and also allows adaptation of the life extending controller module to augment a conventional performance controller of a rocket engine. The nonlinear aspect of the design is achieved using nonlinear parameter optimization of a prescribed control structure.

Research and application of borehole structure optimization based on pre-drill risk assessment

NASA Astrophysics Data System (ADS)

Zhang, Guohui; Liu, Xinyun; Chenrong; Hugui; Yu, Wenhua; Sheng, Yanan; Guan, Zhichuan

2017-11-01

Borehole structure design based on pre-drill risk assessment and considering risks related to drilling operation is the pre-condition for safe and smooth drilling operation. Major risks of drilling operation include lost circulation, blowout, sidewall collapsing, sticking and failure of drilling tools etc. In the study, studying data from neighboring wells was used to calculate the profile of formation pressure with credibility in the target well, then the borehole structure design for the target well assessment by using the drilling risk assessment to predict engineering risks before drilling. Finally, the prediction results were used to optimize borehole structure design to prevent such drilling risks. The newly-developed technique provides a scientific basis for lowering probability and frequency of drilling engineering risks, and shortening time required to drill a well, which is of great significance for safe and high-efficient drilling.

The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology: Capabilities and Applications

NASA Technical Reports Server (NTRS)

Evers, Ken H.; Bachert, Robert F.

1987-01-01

The IDEAL (Integrated Design and Engineering Analysis Languages) modeling methodology has been formulated and applied over a five-year period. It has proven to be a unique, integrated approach utilizing a top-down, structured technique to define and document the system of interest; a knowledge engineering technique to collect and organize system descriptive information; a rapid prototyping technique to perform preliminary system performance analysis; and a sophisticated simulation technique to perform in-depth system performance analysis.

Ascent performance feasibility for next-generation spacecraft

NASA Astrophysics Data System (ADS)

Mancuso, Salvatore Massimo

This thesis deals with the optimization of the ascent trajectories for single-stage suborbital (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem has been solved using the sequential gradient-restoration algorithm. For the TSTO case, some modifications to the original version of the algorithm have been necessary in order to deal with discontinuities due to staging and the fact that the functional being minimized depends on interface conditions. The optimization problem is studied for different values of the initial thrust-to-weight ratio in the range 1.3 to 1.6, engine specific impulse in the range 400 to 500 sec, and spacecraft structural factor in the range 0.08 to 0.12. For the TSTO configuration, two subproblems are studied: uniform structural factor between stages and nonuniform structural factor between stages. Due to the regular behavior of the results obtained, engineering approximations have been developed which connect the maximum payload weight to the engine specific impulse and spacecraft structural factor; in turn, this leads to useful design considerations. Also, performance sensitivity to the scale of the aerodynamic drag is studied, and it is shown that its effect on payload weight is relatively small, even for drag changes approaching ± 50%. The main conclusions are that: the design of a SSSO configuration appears to be feasible; the design of a SSTO configuration might be comfortably feasible, marginally feasible, or unfeasible, depending on the parameter values assumed; the design of a TSTO configuration is not only feasible, but its payload appears to be considerably larger than that of a SSTO configuration. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, it appears that aerodynamic improvements do not yield significant improvements in payload weight.

Optimization of monopiles for offshore wind turbines.

PubMed

Kallehave, Dan; Byrne, Byron W; LeBlanc Thilsted, Christian; Mikkelsen, Kristian Kousgaard

2015-02-28

The offshore wind industry currently relies on subsidy schemes to be competitive with fossil-fuel-based energy sources. For the wind industry to survive, it is vital that costs are significantly reduced for future projects. This can be partly achieved by introducing new technologies and partly through optimization of existing technologies and design methods. One of the areas where costs can be reduced is in the support structure, where better designs, cheaper fabrication and quicker installation might all be possible. The prevailing support structure design is the monopile structure, where the simple design is well suited to mass-fabrication, and the installation approach, based on conventional impact driving, is relatively low-risk and robust for most soil conditions. The range of application of the monopile for future wind farms can be extended by using more accurate engineering design methods, specifically tailored to offshore wind industry design. This paper describes how state-of-the-art optimization approaches are applied to the design of current wind farms and monopile support structures and identifies the main drivers where more accurate engineering methods could impact on a next generation of highly optimized monopiles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Cognitive engineering and health informatics: Applications and intersections.

PubMed

Hettinger, A Zachary; Roth, Emilie M; Bisantz, Ann M

2017-03-01

Cognitive engineering is an applied field with roots in both cognitive science and engineering that has been used to support design of information displays, decision support, human-automation interaction, and training in numerous high risk domains ranging from nuclear power plant control to transportation and defense systems. Cognitive engineering provides a set of structured, analytic methods for data collection and analysis that intersect with and complement methods of Cognitive Informatics. These methods support discovery of aspects of the work that make performance challenging, as well as the knowledge, skills, and strategies that experts use to meet those challenges. Importantly, cognitive engineering methods provide novel representations that highlight the inherent complexities of the work domain and traceable links between the results of cognitive analyses and actionable design requirements. This article provides an overview of relevant cognitive engineering methods, and illustrates how they have been applied to the design of health information technology (HIT) systems. Additionally, although cognitive engineering methods have been applied in the design of user-centered informatics systems, methods drawn from informatics are not typically incorporated into a cognitive engineering analysis. This article presents a discussion regarding ways in which data-rich methods can inform cognitive engineering. Copyright © 2017 Elsevier Inc. All rights reserved.

Space Engineering Projects in Design Methodology

NASA Technical Reports Server (NTRS)

Crawford, R.; Wood, K.; Nichols, S.; Hearn, C.; Corrier, S.; DeKunder, G.; George, S.; Hysinger, C.; Johnson, C.; Kubasta, K.

1993-01-01

NASA/USRA is an ongoing sponsor of space design projects in the senior design courses of the Mechanical Engineering Department at The University of Texas at Austin. This paper describes the UT senior design sequence, focusing on the first-semester design methodology course. The philosophical basis and pedagogical structure of this course is summarized. A history of the Department's activities in the Advanced Design Program is then presented. The paper includes a summary of the projects completed during the 1992-93 Academic Year in the methodology course, and concludes with an example of two projects completed by student design teams.

Design Protocols and Analytical Strategies that Incorporate Structural Reliability Models

NASA Technical Reports Server (NTRS)

Duffy, Stephen F.

1995-01-01

The general goal of this project is to establish design protocols that enable the engineer to analyze and predict certain types of behavior in ceramic composites. Sections of the final report addresses the following: Description of the Problem that Motivated the Technology Development, Description of the New Technology that was Developed, Unique and Novel Features of the Technology and Results/Benefits of Application (year by year accomplishments), and Utilization of New Technology in Non-Aerospace Applications. Activities for this reporting period included the development of a design analysis as part of a cooperative agreement with general Electric Aircraft Engines. The effort focused on modifying the Toughened Ceramics Analysis and Reliability Evaluation of Structures (TCARES) algorithm for use in the design of engine components fabricated from NiAl. Other activities related to the development of an ASTM standard practice for estimating Weibull parameters. The standard focuses on the evaluation and reporting of uniaxial strength data, and the estimation of probability distribution parameters for ceramics which fail in a brittle fashion.

Advanced Gas Turbine (AGT) powertrain system development for automotive applications

NASA Technical Reports Server (NTRS)

1984-01-01

Rotor dynamic instability investigations were conducted. Forward ball bearing hydraulic mount configurations were tested with little effect. Trial assembly of S/N 002 ceramic engine was initiated. Impeller design activities were completed on the straight line element (SLE) blade definition to address near-net-shape powder metal die forging. Performance characteristics of the Baseline Test 2A impeller were closely preserved. The modified blading design has been released for tooling procurement. Developmental testing of the diffusion flame combustor (DFC) for initial use in the S/N 002 2100 F ceramic structures engine was completed. A natural gas slave preheater was designed and fabricated. Preliminary regenerator static seal rig testing showed a significant reduction in leakage and sensitivity to stack height. Ceramic screening tests were completed and two complete sets of ceramic static structures were qualified for engine testing. Efforts on rotor dynamics development to resolve subsynchronous motion were continued.

Concise Review: Organ Engineering: Design, Technology, and Integration.

PubMed

Kaushik, Gaurav; Leijten, Jeroen; Khademhosseini, Ali

2017-01-01

Engineering complex tissues and whole organs has the potential to dramatically impact translational medicine in several avenues. Organ engineering is a discipline that integrates biological knowledge of embryological development, anatomy, physiology, and cellular interactions with enabling technologies including biocompatible biomaterials and biofabrication platforms such as three-dimensional bioprinting. When engineering complex tissues and organs, core design principles must be taken into account, such as the structure-function relationship, biochemical signaling, mechanics, gradients, and spatial constraints. Technological advances in biomaterials, biofabrication, and biomedical imaging allow for in vitro control of these factors to recreate in vivo phenomena. Finally, organ engineering emerges as an integration of biological design and technical rigor. An overall workflow for organ engineering and guiding technology to advance biology as well as a perspective on necessary future iterations in the field is discussed. Stem Cells 2017;35:51-60. © 2016 AlphaMed Press.

Numerical method to determine mechanical parameters of engineering design in rock masses.

PubMed

Xue, Ting-He; Xiang, Yi-Qiang; Guo, Fa-Zhong

2004-07-01

This paper proposes a new continuity model for engineering in rock masses and a new schematic method for reporting the engineering of rock continuity. This method can be used to evaluate the mechanics of every kind of medium; and is a new way to determine the mechanical parameters used in engineering design in rock masses. In the numerical simulation, the experimental parameters of intact rock were combined with the structural properties of field rock. The experimental results for orthogonally-jointed rock are given. The results included the curves of the stress-strain relationship of some rock masses, the curve of the relationship between the dimension Delta and the uniaxial pressure-resistant strength sc of these rock masses, and pictures of the destructive procedure of some rock masses in uniaxial or triaxial tests, etc. Application of the method to engineering design in rock masses showed the potential of its application to engineering practice.

Research in the comprehension of engineering lectures by non-native speakers

NASA Technical Reports Server (NTRS)

Olsen, L. A.; Huckin, T. N.

1981-01-01

Failure by foreign students to perceive the rhetorical structure or overall organization of an engineering lecture, rendering them unable to understand it, is discussed. Equally serious failure by such students to perceive the organizing role of theory in structuring the activities in their field is reported. Failure to identify the role of theory in the problem-solving process that underlies engineering is emphasized. Engineering was not seen as a series of on-going problems where each stage of solution exposed new problems to be solved. Implications for course planners and material designers are discussed.

Flexible structure control experiments using a real-time workstation for computer-aided control engineering

NASA Technical Reports Server (NTRS)

Stieber, Michael E.

1989-01-01

A Real-Time Workstation for Computer-Aided Control Engineering has been developed jointly by the Communications Research Centre (CRC) and Ruhr-Universitaet Bochum (RUB), West Germany. The system is presently used for the development and experimental verification of control techniques for large space systems with significant structural flexibility. The Real-Time Workstation essentially is an implementation of RUB's extensive Computer-Aided Control Engineering package KEDDC on an INTEL micro-computer running under the RMS real-time operating system. The portable system supports system identification, analysis, control design and simulation, as well as the immediate implementation and test of control systems. The Real-Time Workstation is currently being used by CRC to study control/structure interaction on a ground-based structure called DAISY, whose design was inspired by a reflector antenna. DAISY emulates the dynamics of a large flexible spacecraft with the following characteristics: rigid body modes, many clustered vibration modes with low frequencies and extremely low damping. The Real-Time Workstation was found to be a very powerful tool for experimental studies, supporting control design and simulation, and conducting and evaluating tests withn one integrated environment.

Microfabrication of hierarchical structures for engineered mechanical materials

NASA Astrophysics Data System (ADS)

Vera Canudas, Marc

Materials found in nature present, in some cases, unique properties from their constituents that are of great interest in engineered materials for applications ranging from structural materials for the construction of bridges, canals and buildings to the fabrication of new lightweight composites for airplane and automotive bodies, to protective thin film coatings, amongst other fields. Research in the growing field of biomimetic materials indicates that the micro-architectures present in natural materials are critical to their macroscopic mechanical properties. A better understanding of the effect that structure and hierarchy across scales have on the material properties will enable engineered materials with enhanced properties. At the moment, very few theoretical models predict mechanical properties of simple materials based on their microstructures. Moreover these models are based on observations from complex biological systems. One way to overcome this challenge is through the use of microfabrication techniques to design and fabricate simple materials, more appropriate for the study of hierarchical organizations and microstructured materials. Arrays of structures with controlled geometry and dimension can be designed and fabricated at different length scales, ranging from a few hundred nanometers to centimeters, in order to mimic similar systems found in nature. In this thesis, materials have been fabricated in order to gain fundamental insight into the complex hierarchical materials found in nature and to engineer novel materials with enhanced mechanical properties. The materials fabricated here were mechanically characterized and compared to simple mechanics models to describe their behavior with the goal of applying the knowledge acquired to the design and synthesis of future engineered materials with novel properties.

Structures and geriatrics from a failure analysis experience viewpoint

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

Hopper, D.M.

In a failure analysis consulting engineering practice one sees a variety of structural failures from which observations may be made concerning geriatric structures. Representative experience with power plants, refineries, offshore structures, and forensic investigations is summarized and generic observations are made regarding the maintenance of fitness for purpose of structures. Although it is important to optimize the engineering design for a range of operational and environmental variables, it is essential that fabrication and inspection controls exist along with common sense based ongoing monitoring and operations procedures. 18 figs.

CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge

NASA Astrophysics Data System (ADS)

Qiu, Yi Mei; Wen, Sen Yuan; Chen, Jun Xiang

2018-06-01

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.

Industrializing Offshore Wind Power with Serial Assembly and Lower-cost Deployment - Final Report

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

Kempton, Willett

A team of engineers and contractors has developed a method to move offshore wind installation toward lower cost, faster deployment, and lower environmental impact. A combination of methods, some incremental and some breaks from past practice, interact to yield multiple improvements. Three designs were evaluated based on detailed engineering: 1) a 5 MW turbine on a jacket with pin piles (base case), 2) a 10 MW turbine on a conventional jacket with pin piles, assembled at sea, and 3) a 10 MW turbine on tripod jacket with suction buckets (caissons) and with complete turbine assembly on-shore. The larger turbine, assemblymore » ashore, and the use of suction buckets together substantially reduce capital cost of offshore wind projects. Notable capital cost reductions are: changing from 5 MW to 10 MW turbine, a 31% capital cost reduction, and assembly on land then single-piece install at sea an additional 9% capital cost reduction. An estimated Design 4) estimates further cost reduction when equipment and processes of Design 3) are optimized, rather than adapted to existing equipment and process. Cost of energy for each of the four Designs are also calculated, yielding approximately the same percentage reductions. The methods of Design 3) analyzed here include accepted structures such as suction buckets used in new ways, innovations conceived but previously without engineering and economic validation, combined with new methods not previously proposed. Analysis of Designs 2) and 3) are based on extensive engineering calculations and detailed cost estimates. All design methods can be done with existing equipment, including lift equipment, ports and ships (except that design 4 assumes a more optimized ship). The design team consists of experienced offshore structure designers, heavy lift engineers, wind turbine designers, vessel operators, and marine construction contractors. Comparing the methods based on criteria of cost and deployment speed, the study selected the third design. That design is, in brief: a conventional turbine and tubular tower is mounted on a tripod jacket, in turn atop three suction buckets. Blades are mounted on the tower, not on the hub. The entire structure is built in port, from the bottom up, then assembled structures are queued in the port for deployment. During weather windows, the fully-assembled structures are lifted off the quay, lashed to the vessel, and transported to the deployment site. The vessel analyzed is a shear leg crane vessel with dynamic positioning like the existing Gulliver, or it could be a US-built crane barge. On site, the entire structure is lowered to the bottom by the crane vessel, then pumping of the suction buckets is managed by smaller service vessels. Blades are lifted into place by small winches operated by workers in the nacelle without lift vessel support. Advantages of the selected design include: cost and time at sea of the expensive lift vessel are significantly reduced; no jack up vessel is required; the weather window required for each installation is shorter; turbine structure construction is continuous with a queue feeding the weather-dependent installation process; pre-installation geotechnical work is faster and less expensive; there are no sound impacts on marine mammals, thus minimal spotting and no work stoppage Industrializing Offshore Wind Power 6 of 96 9 for mammal passage; the entire structure can be removed for decommissioning or major repairs; the method has been validated for current turbines up to 10 MW, and a calculation using simple scaling shows it usable up to 20 MW turbines.« less

Selected Core Thinking Skills and Cognitive Strategy of an Expert and Novice Engineer

ERIC Educational Resources Information Center

Dixon, Raymond A.

2011-01-01

This exploratory study highlights certain differences in the way an expert and a novice engineer used their analyzing and generating skills while solving a fairly ill-structured design problem. The expert tends to use more inferences and elaboration when solving the design problem and the novice tend to use analysis that is focused on the…

Large space telescope engineering scale model optical design

NASA Technical Reports Server (NTRS)

Facey, T. A.

1973-01-01

The objective is to develop the detailed design and tolerance data for the LST engineering scale model optical system. This will enable MSFC to move forward to the optical element procurement phase and also to evaluate tolerances, manufacturing requirements, assembly/checkout procedures, reliability, operational complexity, stability requirements of the structure and thermal system, and the flexibility to change and grow.

QUICK - An interactive software environment for engineering design

NASA Technical Reports Server (NTRS)

Skinner, David L.

1989-01-01

QUICK, an interactive software environment for engineering design, provides a programmable FORTRAN-like calculator interface to a wide range of data structures as well as both built-in and user created functions. QUICK also provides direct access to the operating systems of eight different machine architectures. The evolution of QUICK and a brief overview of the current version are presented.

Using in-cell SHAPE-Seq and simulations to probe structure-function design principles of RNA transcriptional regulators.

PubMed

Takahashi, Melissa K; Watters, Kyle E; Gasper, Paul M; Abbott, Timothy R; Carlson, Paul D; Chen, Alan A; Lucks, Julius B

2016-06-01

Antisense RNA-mediated transcriptional regulators are powerful tools for controlling gene expression and creating synthetic gene networks. RNA transcriptional repressors derived from natural mechanisms called attenuators are particularly versatile, though their mechanistic complexity has made them difficult to engineer. Here we identify a new structure-function design principle for attenuators that enables the forward engineering of new RNA transcriptional repressors. Using in-cell SHAPE-Seq to characterize the structures of attenuator variants within Escherichia coli, we show that attenuator hairpins that facilitate interaction with antisense RNAs require interior loops for proper function. Molecular dynamics simulations of these attenuator variants suggest these interior loops impart structural flexibility. We further observe hairpin flexibility in the cellular structures of natural RNA mechanisms that use antisense RNA interactions to repress translation, confirming earlier results from in vitro studies. Finally, we design new transcriptional attenuators in silico using an interior loop as a structural requirement and show that they function as desired in vivo. This work establishes interior loops as an important structural element for designing synthetic RNA gene regulators. We anticipate that the coupling of experimental measurement of cellular RNA structure and function with computational modeling will enable rapid discovery of structure-function design principles for a diverse array of natural and synthetic RNA regulators. © 2016 Takahashi et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Apollo Lightcraft Project

NASA Technical Reports Server (NTRS)

Myrabo, Leik N.; Atonison, Mark A. (Editor); Chen, Sammy G. (Editor); Decusatis, Casimer (Editor); Kusche, Karl P. (Editor); Minucci, Marco A. (Editor); Moder, Jeffrey P. (Editor); Morales, Ciro (Editor); Nelson, Caroline V. (Editor); Richard, Jacques C. (Editor)

1989-01-01

The ultimate goal for this NASA/USRA-sponsored Apollo Lightcraft Project is to develop a revolutionary manned launch vehicle technology which can potentially reduce payload transport costs by a factor of 1000 below the Space Shuttle Orbiter. The Rensselaer design team proposes to utilize advanced, highly energetic, beamed-energy sources (laser, microwave) and innovative combined-cycle (airbreathing/rocket) engines to accomplish this goal. The research effort focuses on the concept of a 100 MW-class, laser-boosted Lightcraft Technology Demonstrator (LTD) drone. The preliminary conceptual design of this 1.4 meter diameter microspacecraft involved an analytical performance analysis of the transatmospheric engine in its two modes of operation (including an assessment of propellant and tankage requirements), and a detailed design of internal structure and external aeroshell configuration. The central theme of this advanced propulsion research was to pick a known excellent working fluid (i.e., air or LN sub 2), and then to design a combined-cycle engine concept around it. Also, a structural vibration analysis was performed on the annular shroud pulsejet engine. Finally, the sensor satellite mission was examined to identify the requisite subsystem hardware: e.g., electrical power supply, optics and sensors, communications and attitude control systems.

Lessons Learned During Solutions of Multidisciplinary Design Optimization Problems

NASA Technical Reports Server (NTRS)

Patnaik, Suna N.; Coroneos, Rula M.; Hopkins, Dale A.; Lavelle, Thomas M.

2000-01-01

Optimization research at NASA Glenn Research Center has addressed the design of structures, aircraft and airbreathing propulsion engines. During solution of the multidisciplinary problems several issues were encountered. This paper lists four issues and discusses the strategies adapted for their resolution: (1) The optimization process can lead to an inefficient local solution. This deficiency was encountered during design of an engine component. The limitation was overcome through an augmentation of animation into optimization. (2) Optimum solutions obtained were infeasible for aircraft and air-breathing propulsion engine problems. Alleviation of this deficiency required a cascading of multiple algorithms. (3) Profile optimization of a beam produced an irregular shape. Engineering intuition restored the regular shape for the beam. (4) The solution obtained for a cylindrical shell by a subproblem strategy converged to a design that can be difficult to manufacture. Resolution of this issue remains a challenge. The issues and resolutions are illustrated through six problems: (1) design of an engine component, (2) synthesis of a subsonic aircraft, (3) operation optimization of a supersonic engine, (4) design of a wave-rotor-topping device, (5) profile optimization of a cantilever beam, and (6) design of a cvlindrical shell. The combined effort of designers and researchers can bring the optimization method from academia to industry.

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.

Aeropropulsion 1979. [conferences

NASA Technical Reports Server (NTRS)

1979-01-01

State of the art technology in aeronautical propulsion is assessed. Noise and air pollution control techniques, advances in supersonic propulsion for transport aircraft, and composite materials and structures for reliable engine components are covered along with engine design for improved fuel consumption.

Multidisciplinary Analysis of a Hypersonic Engine

NASA Technical Reports Server (NTRS)

Stewart, M. E. M.; Suresh, A.; Liou, M. S.; Owen, A. K.; Messitt, D. G.

2002-01-01

This paper describes implementation of a technique used to obtain a high fidelity fluid-thermal-structural solution of a combined cycle engine at its scram design point. Single-discipline simulations are insufficient here since interactions from other disciplines are significant. Using off-the-shelf, validated solvers for the fluid, chemistry, thermal, and structural solutions, this approach couples together their results to obtain consistent solutions.

Vibrational impacts of hush house operation

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

Witten, A.J.

1988-01-01

United States Air Force (USAF) facilities are required to test turboprop and turbojet engines before or after maintenance or repair and prior to installation on aircraft to ensure that no problems were introduced or remain uncorrected. This requirement prevents the installation of engines in aircraft which require further maintenance. There are a number of facilities in use by USAF for conducting engine diagnostic tests. The most modern of these facilities is the hush house which is a hangar-like structure designed to isolate the noise associated with extended engine operations from the surrounding environment. One type of hush house, the T-10,more » is of particular concern because of vibrational impacts to surrounding structures induced by subaudible sound (infrasound) emitted during operation. While these facilities fulfill the design requirement of reducing audible noise, serious siting problems have been reported at several installations because of infrasound-induced vibrations. The worst of these include the abandonment of an avionics laboratory because induced vibrations interfered with this facilities function and structural damage to a concrete block maintenance facility. This paper describes a predictive method for assessing vibration-driven structural impacts. 9 refs., 2 figs.« less

The J-2X Fuel Turbopump - Design, Development, and Test

NASA Technical Reports Server (NTRS)

Tellier, James G.; Hawkins, Lakiesha V.; Shinguchi, Brian H.; Marsh, Matthew W.

2011-01-01

Pratt and Whitney Rocketdyne (PWR), a NASA subcontractor, is executing the design, development, test, and evaluation (DDT&E) of a liquid oxygen, liquid hydrogen two hundred ninety four thousand pound thrust rocket engine initially intended for the Upper Stage (US) and Earth Departure Stage (EDS) of the Constellation Program Ares-I Crew Launch Vehicle (CLV). A key element of the design approach was to base the new J-2X engine on the heritage J-2S engine with the intent of uprating the engine and incorporating SSME and RS-68 lessons learned. The J-2S engine was a design upgrade of the flight proven J-2 configuration used to put American astronauts on the moon. The J-2S Fuel Turbopump (FTP) was the first Rocketdyne-designed liquid hydrogen centrifugal pump and provided many of the early lessons learned for the Space Shuttle Main Engine High Pressure Fuel Turbopumps. This paper will discuss the design trades and analyses performed for the current J-2X FTP to increase turbine life; increase structural margins, facilitate component fabrication; expedite turbopump assembly; and increase rotordynamic stability margins. Risk mitigation tests including inducer water tests, whirligig turbine blade tests, turbine air rig tests, and workhorse gas generator tests characterized operating environments, drove design modifications, or identified performance impact. Engineering design, fabrication, analysis, and assembly activities support FTP readiness for the first J-2X engine test scheduled for July 2011.

Test Plan. GCPS Task 4, subtask 4.2 thrust structure development

NASA Astrophysics Data System (ADS)

Greenberg, H. S.

1994-09-01

The Single Stage To Orbit (SSTO) vehicle is designed to lift off from a vertical position, go into orbit, return to earth for a horizontal landing, and be reusable for the next mission. (NASA baseline only) In order to meet its performance goals, the SSTO relies on light weight structure and the use of 8 tri-propellant engines. These engines are mounted to the thrust structure. This test plan addresses selection of the material for this structure, and the integrity of the design through testing of elements and a full-scale subcomponent. This test plan supports the development of the design for an advanced composite thrust structure for a Single Stage to Orbit manned, heavy launch vehicle. The thrust structure is designed to transmit very high thrust loads from the engines to the rest of the vehicle (see Figure 1 ). The thrust structure will also be used for primary attachment of the twin vertical tails and possibly act as the aft attach point for the wing. The combination of high loading, high vibration, long service life and high acoustic environments will need to be evaluated by tests. To minimize design risk, a building block approach will be used. We will first screen materials to determine which materials show the most promise for this application. Factors in this screening will be the suitability of these materials for chosen design concepts, particularly concerning specific strength, environmental compatibility and applicability to fabrication processes. Next we will characterize two material systems that will be used in the design; the characterization will allow us to generate preliminary design data that will be used for the analysis. Element testing will be performed to evaluate critical structural locations under load. Final testing on the full scale test article will be performed to verify the design and to demonstrate predictability of the analysis. Additionally, risks associated with fabricating full scale thrust structures will be reduced through testing activities. One of the major concerns that stems from full scale fabrication is the realities of size and the associated complexities of handling, manufacturing, and assembly. The need exists to fabricate, assemble and test_representative joint specimens to achieve_confidence in the design and manufacturing technologies being proposed.

Test Plan. GCPS Task 4, subtask 4.2 thrust structure development

NASA Technical Reports Server (NTRS)

Greenberg, H. S.

1994-01-01

The Single Stage To Orbit (SSTO) vehicle is designed to lift off from a vertical position, go into orbit, return to earth for a horizontal landing, and be reusable for the next mission. (NASA baseline only) In order to meet its performance goals, the SSTO relies on light weight structure and the use of 8 tri-propellant engines. These engines are mounted to the thrust structure. This test plan addresses selection of the material for this structure, and the integrity of the design through testing of elements and a full-scale subcomponent. This test plan supports the development of the design for an advanced composite thrust structure for a Single Stage to Orbit manned, heavy launch vehicle. The thrust structure is designed to transmit very high thrust loads from the engines to the rest of the vehicle (see Figure 1 ). The thrust structure will also be used for primary attachment of the twin vertical tails and possibly act as the aft attach point for the wing. The combination of high loading, high vibration, long service life and high acoustic environments will need to be evaluated by tests. To minimize design risk, a building block approach will be used. We will first screen materials to determine which materials show the most promise for this application. Factors in this screening will be the suitability of these materials for chosen design concepts, particularly concerning specific strength, environmental compatibility and applicability to fabrication processes. Next we will characterize two material systems that will be used in the design; the characterization will allow us to generate preliminary design data that will be used for the analysis. Element testing will be performed to evaluate critical structural locations under load. Final testing on the full scale test article will be performed to verify the design and to demonstrate predictability of the analysis. Additionally, risks associated with fabricating full scale thrust structures will be reduced through testing activities. One of the major concerns that stems from full scale fabrication is the realities of size and the associated complexities of handling, manufacturing, and assembly. The need exists to fabricate, assemble and test_representative joint specimens to achieve_confidence in the design and manufacturing technologies being proposed.

Systems engineering for very large systems

NASA Technical Reports Server (NTRS)

Lewkowicz, Paul E.

1993-01-01

Very large integrated systems have always posed special problems for engineers. Whether they are power generation systems, computer networks or space vehicles, whenever there are multiple interfaces, complex technologies or just demanding customers, the challenges are unique. 'Systems engineering' has evolved as a discipline in order to meet these challenges by providing a structured, top-down design and development methodology for the engineer. This paper attempts to define the general class of problems requiring the complete systems engineering treatment and to show how systems engineering can be utilized to improve customer satisfaction and profit ability. Specifically, this work will focus on a design methodology for the largest of systems, not necessarily in terms of physical size, but in terms of complexity and interconnectivity.

Systems engineering for very large systems

NASA Astrophysics Data System (ADS)

Lewkowicz, Paul E.

Very large integrated systems have always posed special problems for engineers. Whether they are power generation systems, computer networks or space vehicles, whenever there are multiple interfaces, complex technologies or just demanding customers, the challenges are unique. 'Systems engineering' has evolved as a discipline in order to meet these challenges by providing a structured, top-down design and development methodology for the engineer. This paper attempts to define the general class of problems requiring the complete systems engineering treatment and to show how systems engineering can be utilized to improve customer satisfaction and profit ability. Specifically, this work will focus on a design methodology for the largest of systems, not necessarily in terms of physical size, but in terms of complexity and interconnectivity.

System analysis of a piston steam engine employing the uniflow principle, a study in optimized performance

NASA Technical Reports Server (NTRS)

Peoples, J. A.

1975-01-01

Results are reported which were obtained from a mathematical model of a generalized piston steam engine configuration employing the uniflow principal. The model accounted for the effects of clearance volume, compression work, and release volume. A simple solution is presented which characterizes optimum performance of the steam engine, based on miles per gallon. Development of the mathematical model is presented. The relationship between efficiency and miles per gallon is developed. An approach to steam car analysis and design is presented which has purpose rather than lucky hopefulness. A practical engine design is proposed which correlates to the definition of the type engine used. This engine integrates several system components into the engine structure. All conclusions relate to the classical Rankine Cycle.

A Virtual Steel Sculpture for Structural Engineering Education: Development and Initial Findings

ERIC Educational Resources Information Center

Dib, Hazar Nicholas; Adamo-Villani, Nicoletta

2016-01-01

We describe the development and evaluation of a virtual steel sculpture for engineering education. A good connection design requires the engineer to have a solid understanding of the mechanics and steel behavior. To help students better understand various connection types, many schools have acquired steel sculptures. A steel sculpture is a…

Virtual Bridge Design Challenge

ERIC Educational Resources Information Center

Mitts, Charles R.

2013-01-01

This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

Recent Advances in Multidisciplinary Analysis and Optimization, part 3

NASA Technical Reports Server (NTRS)

Barthelemy, Jean-Francois M. (Editor)

1989-01-01

This three-part document contains a collection of technical papers presented at the Second NASA/Air Force Symposium on Recent Advances in Multidisciplinary Analysis and Optimization, held September 28-30, 1988 in Hampton, Virginia. The topics covered include: aircraft design, aeroelastic tailoring, control of aeroelastic structures, dynamics and control of flexible structures, structural design, design of large engineering systems, application of artificial intelligence, shape optimization, software development and implementation, and sensitivity analysis.

Recent Advances in Multidisciplinary Analysis and Optimization, part 2

NASA Technical Reports Server (NTRS)

Barthelemy, Jean-Francois M. (Editor)

1989-01-01

This three-part document contains a collection of technical papers presented at the Second NASA/Air Force Symposium on Recent Advances in Multidisciplinary Analysis and Optimization, held September 28-30, 1988 in Hampton, Virginia. The topics covered include: helicopter design, aeroelastic tailoring, control of aeroelastic structures, dynamics and control of flexible structures, structural design, design of large engineering systems, application of artificial intelligence, shape optimization, software development and implementation, and sensitivity analysis.

Recent Advances in Multidisciplinary Analysis and Optimization, part 1

NASA Technical Reports Server (NTRS)

Barthelemy, Jean-Francois M. (Editor)

1989-01-01

This three-part document contains a collection of technical papers presented at the Second NASA/Air Force Symposium on Recent Advances in Multidisciplinary Analysis and Optimization, held September 28-30, 1988 in Hampton, Virginia. The topics covered include: helicopter design, aeroelastic tailoring, control of aeroelastic structures, dynamics and control of flexible structures, structural design, design of large engineering systems, application of artificial intelligence, shape optimization, software development and implementation, and sensitivity analysis.

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5.

PubMed

Azoitei, M L; Ban, Y A; Kalyuzhny, O; Guenaga, J; Schroeter, A; Porter, J; Wyatt, R; Schief, William R

2014-10-01

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of predefined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of human immunodeficiency virus 1 (HIV-1) neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with subnanomolar affinity (K(D) = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity. © 2014 Wiley Periodicals, Inc.

10 CFR 830.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... Critical assembly means special nuclear devices designed and used to sustain nuclear reactions, which may... reaction becomes self-sustaining. Design features means the design features of a nuclear facility specified..., or the environment, including (1) Physical, design, structural, and engineering features; (2) Safety...

10 CFR 830.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... Critical assembly means special nuclear devices designed and used to sustain nuclear reactions, which may... reaction becomes self-sustaining. Design features means the design features of a nuclear facility specified..., or the environment, including (1) Physical, design, structural, and engineering features; (2) Safety...

Development of Alabama traffic factors for use in mechanistic-empirical pavement design.

DOT National Transportation Integrated Search

2015-02-01

The pavement engineering community is moving toward design practices that use mechanistic-empirical (M-E) approaches to the design and analysis of pavement structures. This effort is : embodied in the Mechanistic-Empirical Pavement Design Guide (MEPD...

Design of a transverse-flux permanent-magnet linear generator and controller for use with a free-piston stirling engine

NASA Astrophysics Data System (ADS)

Zheng, Jigui; Huang, Yuping; Wu, Hongxing; Zheng, Ping

2016-07-01

Transverse-flux with high efficiency has been applied in Stirling engine and permanent magnet synchronous linear generator system, however it is restricted for large application because of low and complex process. A novel type of cylindrical, non-overlapping, transverse-flux, and permanent-magnet linear motor(TFPLM) is investigated, furthermore, a high power factor and less process complexity structure research is developed. The impact of magnetic leakage factor on power factor is discussed, by using the Finite Element Analysis(FEA) model of stirling engine and TFPLM, an optimization method for electro-magnetic design of TFPLM is proposed based on magnetic leakage factor. The relation between power factor and structure parameter is investigated, and a structure parameter optimization method is proposed taking power factor maximum as a goal. At last, the test bench is founded, starting experimental and generating experimental are performed, and a good agreement of simulation and experimental is achieved. The power factor is improved and the process complexity is decreased. This research provides the instruction to design high-power factor permanent-magnet linear generator.

Research on the Diesel Engine with Sliding Mode Variable Structure Theory

NASA Astrophysics Data System (ADS)

Ma, Zhexuan; Mao, Xiaobing; Cai, Le

2018-05-01

This study constructed the nonlinear mathematical model of the diesel engine high-pressure common rail (HPCR) system through two polynomial fitting which was treated as a kind of affine nonlinear system. Based on sliding-mode variable structure control (SMVSC) theory, a sliding-mode controller for affine nonlinear systems was designed for achieving the control of common rail pressure and the diesel engine’s rotational speed. Finally, on the simulation platform of MATLAB, the designed nonlinear HPCR system was simulated. The simulation results demonstrated that sliding-mode variable structure control algorithm shows favourable control performances which are overcoming the shortcomings of traditional PID control in overshoot, parameter adjustment, system precision, adjustment time and ascending time.

30 CFR 817.47 - Hydrologic balance: Discharge structures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Discharge structures. 817...-UNDERGROUND MINING ACTIVITIES § 817.47 Hydrologic balance: Discharge structures. Discharge from sedimentation... the hydrologic balance. Discharge structures shall be designed according to standard engineering...

30 CFR 817.47 - Hydrologic balance: Discharge structures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Discharge structures. 817...-UNDERGROUND MINING ACTIVITIES § 817.47 Hydrologic balance: Discharge structures. Discharge from sedimentation... the hydrologic balance. Discharge structures shall be designed according to standard engineering...

30 CFR 816.47 - Hydrologic balance: Discharge structures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Discharge structures. 816...-SURFACE MINING ACTIVITIES § 816.47 Hydrologic balance: Discharge structures. Discharge from sedimentation... the hydrologic balance. Discharge structures shall be designed according to standard engineering...

30 CFR 816.47 - Hydrologic balance: Discharge structures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Discharge structures. 816...-SURFACE MINING ACTIVITIES § 816.47 Hydrologic balance: Discharge structures. Discharge from sedimentation... the hydrologic balance. Discharge structures shall be designed according to standard engineering...

Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

NASA Technical Reports Server (NTRS)

1983-01-01

The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

Geotechnical engineering for ocean waste disposal. An introduction

USGS Publications Warehouse

Lee, Homa J.; Demars, Kenneth R.; Chaney, Ronald C.; ,

1990-01-01

As members of multidisciplinary teams, geotechnical engineers apply quantitative knowledge about the behavior of earth materials toward designing systems for disposing of wastes in the oceans and monitoring waste disposal sites. In dredge material disposal, geotechnical engineers assist in selecting disposal equipment, predict stable characteristics of dredge mounds, design mound caps, and predict erodibility of the material. In canister disposal, geotechnical engineers assist in specifying canister configurations, predict penetration depths into the seafloor, and predict and monitor canister performance following emplacement. With sewage outfalls, geotechnical engineers design foundation and anchor elements, estimate scour potential around the outfalls, and determine the stability of deposits made up of discharged material. With landfills, geotechnical engineers evaluate the stability and erodibility of margins and estimate settlement and cracking of the landfill mass. Geotechnical engineers also consider the influence that pollutants have on the engineering behavior of marine sediment and the extent to which changes in behavior affect the performance of structures founded on the sediment. In each of these roles, careful application of geotechnical engineering principles can contribute toward more efficient and environmentally safe waste disposal operations.

Engineering of the Magnetized Target Fusion Propulsion System

NASA Technical Reports Server (NTRS)

Statham, G.; White, S.; Adams, R. B.; Thio, Y. C. F.; Santarius, J.; Alexander, R.; Chapman, J.; Fincher, S.; Philips, A.; Polsgrove, T.

2003-01-01

Engineering details are presented for a magnetized target fusion (MTF) propulsion system designed to support crewed missions to the outer solar system. Basic operation of an MTF propulsion system is introduced. Structural, thermal, radiation-management and electrical design details are presented. The propellant storage and supply system design is also presented. A propulsion system mass estimate and associated performance figures are given. The advantages of helium-3 as a fusion fuel for an advanced MTF system are discussed.

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

46 CFR 116.340 - Alternate design considerations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ARRANGEMENT Hull Structure § 116.340 Alternate design considerations. The Commanding Officer, Marine Safety... does not meet the requirements of § 116.300, if it is shown by systematic analysis based on engineering principles that the vessel structure provides adequate safety and strength. An owner seeking approval of an...

Interdisciplinary and multilevel optimum design

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Haftka, Raphael T.

1986-01-01

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.

SPDE/SPRE final summary report

NASA Technical Reports Server (NTRS)

Dochat, George

1993-01-01

Mechanical Technology Incorporated (MTI) performed acceptance testing on the Space Power Research Engine (SPRE), which demonstrated satisfactory operation and sufficient reliability for delivery to NASA Lewis Research Center. The unit produced 13.5 kW PV power with an efficiency of 22 percent versus design goals of 28.8 kW PV power and efficiency of 28 percent. Maximum electric power was only 8 kWe due to lower alternator efficiency. One of the major shortcomings of the SPRE was linear alternator efficiency, which was only 70 percent compared to a design value of 90 percent. It was determined from static tests that the major cause for the efficiency shortfall was the location of the magnetic structure surrounding the linear alternator. Testing of an alternator configuration without a surrounding magnetic structure on a linear dynamometer confirmed earlier static test results. Linear alternator efficiency improved from 70 percent to over 90 percent. Testing of the MTI SPRE was also performed with hydrodynamic bearings and achieved full-stroke, stable operation. This testing indicated that hydrodynamic bearings may be useful in free piston Stirling engines. An important factor in achieving stable operation at design stroke was isolating a portion of the bearing length from the engine pressure variations. In addition, the heat pipe heater head design indicates that integration of a Stirling engine with a heat source can be performed via heat pipes. This design provides a baseline against which alternative designs can be measured.

Interdisciplinary Interactions During R&D and Early Design of Large Engineered Systems

NASA Technical Reports Server (NTRS)

McGowan, Anna-Maria Rivas

2014-01-01

Designing Large-Scale Complex Engineered Systems (LaCES) such as aircraft and submarines requires the input of thousands of engineers and scientists whose work is proximate in neither time nor space. Comprehensive knowledge of the system is dispersed among specialists whose expertise is in typically one system component or discipline. This study examined the interactive work practices among such specialists seeking to improve engineering practice through a rigorous and theoretical understanding of current practice. This research explored current interdisciplinary practices and perspectives during R&D and early LaCES design and identified why these practices and perspectives prevail and persist. The research design consisted of a three-fold, integrative approach that combined an open-ended survey, semi-structured interviews, and ethnography. Significant empirical data from experienced engineers and scientists in a large engineering organization were obtained and integrated with theories from organization science and engineering. Qualitative analysis was used to obtain a holistic, contextualized understanding. The over-arching finding is that issues related to cognition, organization, and social interrelations mostly dominate interactions across disciplines. Engineering issues, such as the integration of hardware or physics-based models, are not as significant. For example, organization culture is an important underlying factor that guided researchers more toward individual sovereignty over cross-disciplinarity. The organization structure and the engineered system architecture also serve as constraints to the engineering work. Many differences in work practices were observed, including frequency and depth of interactions, definition or co-construction of requirements, clarity or creation of the system architecture, work group proximity, and cognitive challenges. Practitioners are often unaware of these differences resulting in confusion and incorrect assumptions regarding work expectations. Cognitively, the enactment and coconstruction of knowledge are the fundamental tasks of the interdisciplinary interactions. Distributed and collective cognition represent most of the efforts. Argument, ignorance, learning, and creativity are interrelated aspects of the interactions that cause discomfort but yield benefits such as problem mitigation, broader understanding, and improved system design and performance. The quality and quantity of social interrelations are central to all work across disciplines with reciprocity, respectful engagement, and heedful interrelations being significant to the effectiveness of the engineering and scientific work.

Data engineering systems: Computerized modeling and data bank capabilities for engineering analysis

NASA Technical Reports Server (NTRS)

Kopp, H.; Trettau, R.; Zolotar, B.

1984-01-01

The Data Engineering System (DES) is a computer-based system that organizes technical data and provides automated mechanisms for storage, retrieval, and engineering analysis. The DES combines the benefits of a structured data base system with automated links to large-scale analysis codes. While the DES provides the user with many of the capabilities of a computer-aided design (CAD) system, the systems are actually quite different in several respects. A typical CAD system emphasizes interactive graphics capabilities and organizes data in a manner that optimizes these graphics. On the other hand, the DES is a computer-aided engineering system intended for the engineer who must operationally understand an existing or planned design or who desires to carry out additional technical analysis based on a particular design. The DES emphasizes data retrieval in a form that not only provides the engineer access to search and display the data but also links the data automatically with the computer analysis codes.

Towards the design of 3D multiscale instructive tissue engineering constructs: Current approaches and trends.

PubMed

Oliveira, Sara M; Reis, Rui L; Mano, João F

2015-11-01

The design of 3D constructs with adequate properties to instruct and guide cells both in vitro and in vivo is one of the major focuses of tissue engineering. Successful tissue regeneration depends on the favorable crosstalk between the supporting structure, the cells and the host tissue so that a balanced matrix production and degradation are achieved. Herein, the major occurring events and players in normal and regenerative tissue are overviewed. These have been inspiring the selection or synthesis of instructive cues to include into the 3D constructs. We further highlight the importance of a multiscale perception of the range of features that can be included on the biomimetic structures. Lastly, we focus on the current and developing tissue-engineering approaches for the preparation of such 3D constructs: top-down, bottom-up and integrative. Bottom-up and integrative approaches present a higher potential for the design of tissue engineering devices with multiscale features and higher biochemical control than top-down strategies, and are the main focus of this review. Copyright © 2015 Elsevier Inc. All rights reserved.

Knowledge-based environment for optical system design

NASA Astrophysics Data System (ADS)

Johnson, R. Barry

1991-01-01

Optical systems are extensively utilized by industry government and military organizations. The conceptual design engineering design fabrication and testing of these systems presently requires significant time typically on the order of 3-5 years. The Knowledge-Based Environment for Optical System Design (KB-OSD) Program has as its principal objectives the development of a methodology and tool(s) that will make a notable reduction in the development time of optical system projects reduce technical risk and overall cost. KB-OSD can be considered as a computer-based optical design associate for system engineers and design engineers. By utilizing artificial intelligence technology coupled with extensive design/evaluation computer application programs and knowledge bases the KB-OSD will provide the user with assistance and guidance to accomplish such activities as (i) develop system level and hardware level requirements from mission requirements (ii) formulate conceptual designs (iii) construct a statement of work for an RFP (iv) develop engineering level designs (v) evaluate an existing design and (vi) explore the sensitivity of a system to changing scenarios. The KB-OSD comprises a variety of computer platforms including a Stardent Titan supercomputer numerous design programs (lens design coating design thermal materials structural atmospherics etc. ) data bases and heuristic knowledge bases. An important element of the KB-OSD Program is the inclusion of the knowledge of individual experts in various areas of optics and optical system engineering. This knowledge is obtained by KB-OSD knowledge engineers performing

Advanced very high resolution radiometer

NASA Technical Reports Server (NTRS)

1978-01-01

The program covered the design, construction, and test of a Breadboard Model, Engineering Model, Protoflight Model, Mechanical/Structural Model, and a Life Test Model. Special bench test and calibration equipment was also developed for use on the program. Initially, the instrument was to operate from a 906 n.mi. orbit and be thermally isolated from the spacecraft. The Breadboard Model and the Mechanical/Structural Model were designed and built to these requirements. The spacecraft altitude was changed to 450 n.mi., IFOVs and spectral characteristics were modified, and spacecraft interfaces were changed. The final spacecraft design provided a temperature-controlled Instrument Mounting Platform (IMP) to carry the AVHRR and other instruments. The design of the AVHRR was modified to these new requirements and the modifications were incorporated in the Engineering Model. The Protoflight Model and the Flight Models conform to this design.

Structural and material approaches to bone tissue engineering in powder-based three-dimensional printing.

PubMed

Butscher, A; Bohner, M; Hofmann, S; Gauckler, L; Müller, R

2011-03-01

This article reviews the current state of knowledge concerning the use of powder-based three-dimensional printing (3DP) for the synthesis of bone tissue engineering scaffolds. 3DP is a solid free-form fabrication (SFF) technique building up complex open porous 3D structures layer by layer (a bottom-up approach). In contrast to traditional fabrication techniques generally subtracting material step by step (a top-down approach), SFF approaches allow nearly unlimited designs and a large variety of materials to be used for scaffold engineering. Today's state of the art materials, as well as the mechanical and structural requirements for bone scaffolds, are summarized and discussed in relation to the technical feasibility of their use in 3DP. Advances in the field of 3DP are presented and compared with other SFF methods. Existing strategies on material and design control of scaffolds are reviewed. Finally, the possibilities and limiting factors are addressed and potential strategies to improve 3DP for scaffold engineering are proposed. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Engine performance analysis and optimization of a dual-mode scramjet with varied inlet conditions

NASA Astrophysics Data System (ADS)

Tian, Lu; Chen, Li-Hong; Chen, Qiang; Zhong, Feng-Quan; Chang, Xin-Yu

2016-02-01

A dual-mode scramjet can operate in a wide range of flight conditions. Higher thrust can be generated by adopting suitable combustion modes. Based on the net thrust, an analysis and preliminary optimal design of a kerosene-fueled parameterized dual-mode scramjet at a crucial flight Mach number of 6 were investigated by using a modified quasi-one-dimensional method and simulated annealing strategy. Engine structure and heat release distributions, affecting the engine thrust, were chosen as analytical parameters for varied inlet conditions (isolator entrance Mach number: 1.5-3.5). Results show that different optimal heat release distributions and structural conditions can be obtained at five different inlet conditions. The highest net thrust of the parameterized dual-mode engine can be achieved by a subsonic combustion mode at an isolator entrance Mach number of 2.5. Additionally, the effects of heat release and scramjet structure on net thrust have been discussed. The present results and the developed analytical method can provide guidance for the design and optimization of high-performance dual-mode scramjets.

Cell–scaffold interaction within engineered tissue

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

Chen, Haiping; Liu, Yuanyuan, E-mail: Yuanyuan_liu@shu.edu.cn; Jiang, Zhenglong

The structure of a tissue engineering scaffold plays an important role in modulating tissue growth. A novel gelatin–chitosan (Gel–Cs) scaffold with a unique structure produced by three-dimensional printing (3DP) technology combining with vacuum freeze-drying has been developed for tissue-engineering applications. The scaffold composed of overall construction, micro-pore, surface morphology, and effective mechanical property. Such a structure meets the essential design criteria of an ideal engineered scaffold. The favorable cell–matrix interaction supports the active biocompatibility of the structure. The structure is capable of supporting cell attachment and proliferation. Cells seeded into this structure tend to maintain phenotypic shape and secreted largemore » amounts of extracellular matrix (ECM) and the cell growth decreased the mechanical properties of scaffold. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique structure, which acts to support cell growth. - Highlights: • The scaffold is not only for providing a surface for cell residence but also for determining cell phenotype and retaining structural integrity. • The mechanical property of scaffold can be affected by activities of cell. • The scaffold provides a microenvironment for cell attachment, growth, and migration.« less

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.

Best Manufacturing Practices Survey Conducted at Litton Data Systems Division, Van Nuys, California

DTIC Science & Technology

1988-10-01

Hardware and Software ................................ 10 DESIGN RELEASE Engineering Change Order Processing and Analysis...structured using bridges to isolate local traffic. Long term plans call for a wide-band network. ENGINEERING CHANGE ORDER PROCESSING AND ANALYSIS

Fracture mechanics /Dryden Lecture/. [aerospace structural design applications

NASA Technical Reports Server (NTRS)

Hardrath, H. F.

1974-01-01

A historical outline of the engineering discipline of fracture mechanics is presented, and current analytical procedures are summarized. The current status of the discipline is assessed, and engineering applications are discussed, along with recommended directions for future study.

Multiple Approaches to Design Education

ERIC Educational Resources Information Center

Fox, Richard L.; And Others

1974-01-01

Discusses implementation of Sloan Foundation projects at the Case Western School of Engineering, including the development of a computer assisted mechanical structural design course, the establishment of a complex systems laboratory, and personnel views of industry-university design projects. (CC)

Architecture earth-sheltered buildings: Design Manual 1.4

NASA Astrophysics Data System (ADS)

1984-03-01

Design guidance is presented for use by experienced engineers and architects. The types of buildings within the scope of this manual include slab-on-grade, partially-buried (bermed) or fully-buried, and large (single-story or multistory) structures. New criteria unique to earth-sheltered design are included for the following disciplines: Planning, Landscape Design, Life-Cycle Analysis, Architectural, Structural, Mechanical (criteria include below-grade heat flux calculation procedures), and Electrical.

Design of a micro-Wankel rotary engine for MEMS fabrication

NASA Astrophysics Data System (ADS)

Jiang, Kyle C.; Prewett, Philip D.; Ward, M. C. L.; Tian, Y.; Yang, H.

2001-04-01

This paper presents the design of a micro Wankel engine for deep etching micro fabrication. The micro engine design is part of a research program in progress to develop a micro actuator to supply torque for driving micro machines. To begin with, the research work concentrates on the micro Wankel engine powered by liquid CO2. Then, a Wankel internal combustion engines will be investigated. The Wankel engine is a planetary rotation engine. It is selected because of its largely 2D structure which is suitable for lithographic processes. The engine has been simplified and redesigned to suit the fabrication processes. In particular, the fuel inlet has been moved to the top cover of the housing from the side, and the outlet is made as a groove on the housing, so that the both parts can be etched. A synchronization valve is mounted on the engine to control the supply of CO2. One of advantages of the micro engines is their high energy density compared with batteries. A research study has been conducted in comparing energy densities of commonly used fuels. It shows that the energy densities of fuels for combustion engines are 10 - 30 times higher than that of batteries. The deigns of the micro Wankel engines have been tested for verification by finite element analysis, CAD assembly, and construction of a prototype, which proves the design is valid.

Using in-cell SHAPE-Seq and simulations to probe structure–function design principles of RNA transcriptional regulators

PubMed Central

Takahashi, Melissa K.; Watters, Kyle E.; Gasper, Paul M.; Abbott, Timothy R.; Carlson, Paul D.; Chen, Alan A.

2016-01-01

Antisense RNA-mediated transcriptional regulators are powerful tools for controlling gene expression and creating synthetic gene networks. RNA transcriptional repressors derived from natural mechanisms called attenuators are particularly versatile, though their mechanistic complexity has made them difficult to engineer. Here we identify a new structure–function design principle for attenuators that enables the forward engineering of new RNA transcriptional repressors. Using in-cell SHAPE-Seq to characterize the structures of attenuator variants within Escherichia coli, we show that attenuator hairpins that facilitate interaction with antisense RNAs require interior loops for proper function. Molecular dynamics simulations of these attenuator variants suggest these interior loops impart structural flexibility. We further observe hairpin flexibility in the cellular structures of natural RNA mechanisms that use antisense RNA interactions to repress translation, confirming earlier results from in vitro studies. Finally, we design new transcriptional attenuators in silico using an interior loop as a structural requirement and show that they function as desired in vivo. This work establishes interior loops as an important structural element for designing synthetic RNA gene regulators. We anticipate that the coupling of experimental measurement of cellular RNA structure and function with computational modeling will enable rapid discovery of structure–function design principles for a diverse array of natural and synthetic RNA regulators. PMID:27103533

Hubble Space Telescope Design Engineering Knowledgebase (HSTDEK)

NASA Technical Reports Server (NTRS)

Johannes, James D.; Everetts, Clark

1989-01-01

The research covered here pays specific attention to the development of tools to assist knowledge engineers in acquiring knowledge and to assist other technical, engineering, and management personnel in automatically performing knowledge capture as part of their everyday work without adding any extra work to what they already do. Requirements for data products, the knowledge base, and methods for mapping knowledge in the documents onto the knowledge representations are discussed, as are some of the difficulties of capturing in the knowledge base the structure of the design process itself, along with a model of the system designed. The capture of knowledge describing the interactions of different components is also discussed briefly.

Structure and Mechanics

NASA Technical Reports Server (NTRS)

Sanger, George

1991-01-01

Artemis is a Common Lunar Lander (CLL) design for the Space Exploration Initiative (SEI). Structure factors for the CLL's primary and secondary structures are listed in tabular form. Additionally, engineering drawings of various systems, including the propulsion and landing systems, are presented.

Recent advances in automated protein design and its future challenges.

PubMed

Setiawan, Dani; Brender, Jeffrey; Zhang, Yang

2018-04-25

Protein function is determined by protein structure which is in turn determined by the corresponding protein sequence. If the rules that cause a protein to adopt a particular structure are understood, it should be possible to refine or even redefine the function of a protein by working backwards from the desired structure to the sequence. Automated protein design attempts to calculate the effects of mutations computationally with the goal of more radical or complex transformations than are accessible by experimental techniques. Areas covered: The authors give a brief overview of the recent methodological advances in computer-aided protein design, showing how methodological choices affect final design and how automated protein design can be used to address problems considered beyond traditional protein engineering, including the creation of novel protein scaffolds for drug development. Also, the authors address specifically the future challenges in the development of automated protein design. Expert opinion: Automated protein design holds potential as a protein engineering technique, particularly in cases where screening by combinatorial mutagenesis is problematic. Considering solubility and immunogenicity issues, automated protein design is initially more likely to make an impact as a research tool for exploring basic biology in drug discovery than in the design of protein biologics.

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

Miller, M.; Kempner, L. Jr.; Mueller, W. III

The concept of an Expert System is not new. It has been around since the days of the early computers when scientists had dreams of robot automation to do everything from washing windows to automobile design. This paper discusses an application of an expert system and addresses software development issues and various levels of expert system development form a structural engineering viewpoint. An expert system designed to aid the structural engineer in first order inelastic analysis of latticed steel transmission powers is presented. The utilization of expert systems with large numerical analysis programs is discussed along with the software developmentmore » of such a system.« less

Advanced Transportation System Studies. Technical Area 3: Alternate Propulsion Subsystem Concepts. Volume 1; Executive Summary

NASA Technical Reports Server (NTRS)

Levack, Daniel J. H.

2000-01-01

The Alternate Propulsion Subsystem Concepts contract had seven tasks defined that are reported under this contract deliverable. The tasks were: FAA Restart Study, J-2S Restart Study, Propulsion Database Development. SSME Upper Stage Use. CERs for Liquid Propellant Rocket Engines. Advanced Low Cost Engines, and Tripropellant Comparison Study. The two restart studies, F-1A and J-2S, generated program plans for restarting production of each engine. Special emphasis was placed on determining changes to individual parts due to obsolete materials, changes in OSHA and environmental concerns, new processes available, and any configuration changes to the engines. The Propulsion Database Development task developed a database structure and format which is easy to use and modify while also being comprehensive in the level of detail available. The database structure included extensive engine information and allows for parametric data generation for conceptual engine concepts. The SSME Upper Stage Use task examined the changes needed or desirable to use the SSME as an upper stage engine both in a second stage and in a translunar injection stage. The CERs for Liquid Engines task developed qualitative parametric cost estimating relationships at the engine and major subassembly level for estimating development and production costs of chemical propulsion liquid rocket engines. The Advanced Low Cost Engines task examined propulsion systems for SSTO applications including engine concept definition, mission analysis. trade studies. operating point selection, turbomachinery alternatives, life cycle cost, weight definition. and point design conceptual drawings and component design. The task concentrated on bipropellant engines, but also examined tripropellant engines. The Tripropellant Comparison Study task provided an unambiguous comparison among various tripropellant implementation approaches and cycle choices, and then compared them to similarly designed bipropellant engines in the SSTO mission This volume overviews each of the tasks giving its objectives, main results. and conclusions. More detailed Final Task Reports are available on each individual task.

Space construction engineering - A new career field

NASA Technical Reports Server (NTRS)

Hagler, T.

1979-01-01

Opportunities for engineers in the design and construction of future large space structures are outlined. Possible space structures for the 1980's include a large mirror to reflect sunlight to earth for night lighting, an antenna for a personal communications system, a deep space communications relay system and a large passive radiometer to measure soil moisture. Considerations in the design of such structures include the lack of gravity, allowing structures to be built with much less supporting weight, the cost of transportation to orbit, leading to the use of aluminum or composite materials stored on reels and attached to a beam builder, and the required surface accuracy in the presence of thermal stresses. Construction factors to consider include the use of astronauts and remote manipulators in assembly, both of which have been demonstrated to be feasible.

Computer-Aided Structural Engineering (CASE) Project. CBASIN--Structural Design of Saint Anthony Falls Stilling Basins According to Corps of Engineers Criteria for Hydraulic Structures. Computer Program X0098

DTIC Science & Technology

1989-08-01

was entered as 1 in line four. Its values are entered under the following prompting message: UNIT WGT UNIT WGT LAT SOIL COEF DEPTH WIDTH MOIST...basins, tuese thick- A67 54 1 16 Hsi/2 : \\l 2 7 >- 9 >- 0x HSl/2 L 3 U- HSV /2 ( \\ i ^\\^ (J-HSl)/2 ! ^ I TYPE(A) i 6 N/2 : 1 2...program uses working stress analysis in accordance with Corps of Engineers EM 1110- 1 -2101, "Working Stresses." C METHODS D. EQUIPMENT DETAILS

Design considerations for a Space Shuttle Main Engine turbine blade made of single crystal material

NASA Technical Reports Server (NTRS)

Abdul-Aziz, A.; August, R.; Nagpal, V.

1993-01-01

Nonlinear finite-element structural analyses were performed on the first stage high-pressure fuel turbopump blade of the Space Shuttle Main Engine. The analyses examined the structural response and the dynamic characteristics at typical operating conditions. Single crystal material PWA-1480 was considered for the analyses. Structural response and the blade natural frequencies with respect to the crystal orientation were investigated. The analyses were conducted based on typical test stand engine cycle. Influence of combined thermal, aerodynamic, and centrifugal loadings was considered. Results obtained showed that the single crystal secondary orientation effects on the maximum principal stresses are not highly significant.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Technical Reports Server (NTRS)

Monell, Donald W.; Piland, William M.

2000-01-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g., manufacturing and systems operation). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often lead to the inability of assessing critical programmatic and technical issues (e.g., cost, risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographical distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across Agency.

Analysis of Stainless Steel Sandwich Panels with a Metal Foam Care for Lightweight Fan Blade Design

NASA Technical Reports Server (NTRS)

Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

2004-01-01

The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. Traditionally, these components have been fabricated using expensive materials such as light weight titanium alloys, polymeric composite materials and carbon-carbon composites. The present study investigates the use of P sandwich foam fan blade made up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The stiffness of the sandwich structure is increased by separating the two face sheets by a foam core. The resulting structure possesses a high stiffness while being lighter than a similar solid construction. Since the face sheets carry the applied bending loads, the sandwich architecture is a viable engineering concept. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of the sandwich structure for a fan blade application. A vibration analysis for natural frequencies and P detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of skin thickness and core volume %re presented with a comparison to a solid titanium blade.

New "Risk-Targeted" Seismic Maps Introduced into Building Codes

USGS Publications Warehouse

Luco, Nicholas; Garrett, B.; Hayes, J.

2012-01-01

Throughout most municipalities of the United States, structural engineers design new buildings using the U.S.-focused International Building Code (IBC). Updated editions of the IBC are published every 3 years. The latest edition (2012) contains new "risk-targeted maximum considered earthquake" (MCER) ground motion maps, which are enabling engineers to incorporate a more consistent and better defined level of seismic safety into their building designs.

Preconceptual design of a fluoride high temperature salt-cooled engineering demonstration reactor: Motivation and overview

DOE PAGES

Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.; ...

2016-12-21

Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate disposal. It is recognized that non-nuclear separate and integral test efforts (e.g., heated salt loops or loops using simulant fluids) are necessary to develop the technologies that will be demonstrated in the FHR DR.« less

Preconceptual design of a fluoride high temperature salt-cooled engineering demonstration reactor: Motivation and overview

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

Qualls, A. Louis; Betzler, Benjamin R.; Brown, Nicholas R.

Engineering demonstration reactors are nuclear reactors built to establish proof of concept for technology options that have never been built. Examples of engineering demonstration reactors include Peach Bottom 1 for high temperature gas-cooled reactors (HTGRs) and Experimental Breeder Reactor-II (EBR-II) for sodium-cooled fast reactors. Historically, engineering demonstrations have played a vital role in advancing the technology readiness level of reactor technologies. Our paper details a preconceptual design for a fluoride salt-cooled engineering demonstration reactor. The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would usemore » tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 7LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. The design philosophy of the FHR DR was focused on safety, near-term deployment, and flexibility. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated as an engineering demonstration with minimal risk and cost. These technologies include TRISO particle fuel, replaceable core structures, and consistent structural material selection for core structures and the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Important capabilities to be demonstrated by building and operating the FHR DR include fabrication and operation of high temperature reactors; heat exchanger performance (including passive decay heat removal); pump performance; and reactivity control; salt chemistry control to maximize vessel life; tritium management; core design methodologies; salt procurement, handling, maintenance and ultimate disposal. It is recognized that non-nuclear separate and integral test efforts (e.g., heated salt loops or loops using simulant fluids) are necessary to develop the technologies that will be demonstrated in the FHR DR.« less

Challenges Facing Design and Analysis Tools

NASA Technical Reports Server (NTRS)

Knight, Norman F., Jr.; Broduer, Steve (Technical Monitor)

2001-01-01

The design and analysis of future aerospace systems will strongly rely on advanced engineering analysis tools used in combination with risk mitigation procedures. The implications of such a trend place increased demands on these tools to assess off-nominal conditions, residual strength, damage propagation, and extreme loading conditions in order to understand and quantify these effects as they affect mission success. Advances in computer hardware such as CPU processing speed, memory, secondary storage, and visualization provide significant resources for the engineer to exploit in engineering design. The challenges facing design and analysis tools fall into three primary areas. The first area involves mechanics needs such as constitutive modeling, contact and penetration simulation, crack growth prediction, damage initiation and progression prediction, transient dynamics and deployment simulations, and solution algorithms. The second area involves computational needs such as fast, robust solvers, adaptivity for model and solution strategies, control processes for concurrent, distributed computing for uncertainty assessments, and immersive technology. Traditional finite element codes still require fast direct solvers which when coupled to current CPU power enables new insight as a result of high-fidelity modeling. The third area involves decision making by the analyst. This area involves the integration and interrogation of vast amounts of information - some global in character while local details are critical and often drive the design. The proposed presentation will describe and illustrate these areas using composite structures, energy-absorbing structures, and inflatable space structures. While certain engineering approximations within the finite element model may be adequate for global response prediction, they generally are inadequate in a design setting or when local response prediction is critical. Pitfalls to be avoided and trends for emerging analysis tools will be described.

U.S. Seismic Design Maps Web Application

NASA Astrophysics Data System (ADS)

Martinez, E.; Fee, J.

2015-12-01

The application computes earthquake ground motion design parameters compatible with the International Building Code and other seismic design provisions. It is the primary method for design engineers to obtain ground motion parameters for multiple building codes across the country. When designing new buildings and other structures, engineers around the country use the application. Users specify the design code of interest, location, and other parameters to obtain necessary ground motion information consisting of a high-level executive summary as well as detailed information including maps, data, and graphs. Results are formatted such that they can be directly included in a final engineering report. In addition to single-site analysis, the application supports a batch mode for simultaneous consideration of multiple locations. Finally, an application programming interface (API) is available which allows other application developers to integrate this application's results into larger applications for additional processing. Development on the application has proceeded in an iterative manner working with engineers through email, meetings, and workshops. Each iteration provided new features, improved performance, and usability enhancements. This development approach positioned the application to be integral to the structural design process and is now used to produce over 1800 reports daily. Recent efforts have enhanced the application to be a data-driven, mobile-first, responsive web application. Development is ongoing, and source code has recently been published into the open-source community on GitHub. Open-sourcing the code facilitates improved incorporation of user feedback to add new features ensuring the application's continued success.

Study on light weight design of truss structures of spacecrafts

NASA Astrophysics Data System (ADS)

Zeng, Fuming; Yang, Jianzhong; Wang, Jian

2015-08-01

Truss structure is usually adopted as the main structure form for spacecrafts due to its high efficiency in supporting concentrated loads. Light-weight design is now becoming the primary concern during conceptual design of spacecrafts. Implementation of light-weight design on truss structure always goes through three processes: topology optimization, size optimization and composites optimization. During each optimization process, appropriate algorithm such as the traditional optimality criterion method, mathematical programming method and the intelligent algorithms which simulate the growth and evolution processes in nature will be selected. According to the practical processes and algorithms, combined with engineering practice and commercial software, summary is made for the implementation of light-weight design on truss structure for spacecrafts.

Topology optimization of a gas-turbine engine part

NASA Astrophysics Data System (ADS)

Faskhutdinov, R. N.; Dubrovskaya, A. S.; Dongauzer, K. A.; Maksimov, P. V.; Trufanov, N. A.

2017-02-01

One of the key goals of aerospace industry is a reduction of the gas turbine engine weight. The solution of this task consists in the design of gas turbine engine components with reduced weight retaining their functional capabilities. Topology optimization of the part geometry leads to an efficient weight reduction. A complex geometry can be achieved in a single operation with the Selective Laser Melting technology. It should be noted that the complexity of structural features design does not affect the product cost in this case. Let us consider a step-by-step procedure of topology optimization by an example of a gas turbine engine part.

Curriculum Outline for Introduction to Engineering Chemistry. Second Edition. Review Cycle-Annual.

ERIC Educational Resources Information Center

Schlenker, Richard M.

Introduction to Engineering Chemistry is a four-credit hour (one semester) course designed to introduce marine engineering students to the rudiments of basic (introductory) inorganic chemistry. The course consists of 18 units (numbered 1.0 through 18.0) focusing on these subject areas: fundamental concepts; structure of the atom and the periodic…

Using the van Hiele K-12 Geometry Learning Theory to Modify Engineering Mechanics Instruction

ERIC Educational Resources Information Center

Sharp, Janet M.; Zachary, Loren W.

2004-01-01

Engineering students use spatial thinking when examining diagrams or models to study structure design. It is expected that most engineering students have solidified spatial thinking skills during K-12 schooling. However, according to what we know about geometry learning and teaching, spatial thinking probably needs to be explicitly taught within…

Design principles of hair-like structures as biological machines

PubMed Central

2018-01-01

Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas. PMID:29848593

Multiple case studies of STEM teachers' orientations to science teaching through engineering design

NASA Astrophysics Data System (ADS)

Rupp, Madeline

The following master's thesis is composed of two manuscripts describing STEM teachers' orientations to science teaching through engineering within the context of the Science Learning through Engineering Design (SLED) partnership. The framework guiding both studies was science teaching orientations, a component of pedagogical content knowledge. Data were collected via semi-structured interviews, multi-day classroom observations, pre- and post-observation interviews, implementation plans, and written reflections. Data sources were analyzed to generate two orientations to science teaching through engineering design for each participant. The first manuscript illustrates a single case study conducted with a sixth grade STEM teacher. Results of this study revealed a detailed picture of the teacher's goals, practices, assessments, and general views when teaching science through engineering design. Common themes across the teacher's instruction were used to characterize her orientations to science teaching through engineering design. Overall, the teacher's orientations showed a shift in her practice from didactic to student-centered methods of teaching as a result of integrating engineering design-based curriculum. The second manuscript describes a comparative case study of two sixth grade SLED participants. Results of this study revealed more complex and diverse relationships between the teachers' orientations to teaching science through engineering design and their instruction. Participants' orientations served as filters for instruction, guided by their divergent purposes for science teaching. Furthermore, their orientations and resulting implementation were developed from knowledge gained in teacher education, implying that teacher educators and researchers can use this framework to learn more about how teachers' knowledge is used to integrate engineering and science practices in the K-12 classroom.

Design and optimization of the micro-engine turbine rotor manufacturing using the rapid prototyping technology

NASA Astrophysics Data System (ADS)

Vdovin, R. A.; Smelov, V. G.

2017-02-01

This work describes the experience in manufacturing the turbine rotor for the micro-engine. It demonstrates the design principles for the complex investment casting process combining the use of the ProCast software and the rapid prototyping techniques. At the virtual modelling stage, in addition to optimized process parameters, the casting structure was improved to obtain the defect-free section. The real production stage allowed demonstrating the performance and fitness of rapid prototyping techniques for the manufacture of geometrically-complex engine-building parts.

Improving aircraft energy efficiency

NASA Technical Reports Server (NTRS)

Povinelli, F. P.; Klineberg, J. M.; Kramer, J. J.

1976-01-01

Investigations conducted by a NASA task force concerning the development of aeronautical fuel-conservation technology are considered. The task force estimated the fuel savings potential, prospects for implementation in the civil air-transport fleet, and the impact of the technology on air-transport fuel use. Propulsion advances are related to existing engines in the fleet, to new production of current engine types, and to new engine designs. Studies aimed at the evolutionary improvement of aerodynamic design and a laminar flow control program are discussed and possibilities concerning the use of composite structural materials are examined.

A Study of Al-Mn Transition Edge Sensor Engineering for Stability

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

George, E. M.; et al.

2013-11-10

The stability of Al-Mn transition edge sensor (TES) bolometers is studied as we vary the engineered TES transition, heat capacity, and/or coupling between the heat capacity and TES. We present thermal structure measurements of each of the 39 designs tested. The data is accurately fit by a two-body bolometer model, which allows us to extract the basic TES parameters that affect device stability. We conclude that parameters affecting device stability can be engineered for optimal device operation, and present the model parameters extracted for the different TES designs.

A 20k Payload Launch Vehicle Fast Track Development Concept Using an RD-180 Engine and a Centaur Upper Stage

NASA Technical Reports Server (NTRS)

Toelle, Ronald (Compiler)

1995-01-01

A launch vehicle concept to deliver 20,000 lb of payload to a 100-nmi orbit has been defined. A new liquid oxygen/kerosene booster powered by an RD-180 engine was designed while using a slightly modified Centaur upper stage. The design, development, and test program met the imposed 40-mo schedule by elimination of major structural testing by increased factors of safety and concurrent engineering concepts. A growth path to attain 65,000 lb of payload is developed.

Moving Metric: Textbooks.

ERIC Educational Resources Information Center

Hauck, George F.

1981-01-01

Lists engineering textbooks that use SI units. Includes author(s), title, publisher, year, and author's or publisher's comments on the use of the SI units. Books are categorized by topic, such as engineering mechanics, mechanics of materials, fluid mechanics, thermodynamics, structural design, and hydrology. (CS)

Design and performance verification of UHPC piles for deep foundations.

DOT National Transportation Integrated Search

2008-11-01

The strategic plan for bridge engineering issued by AASHTO in 2005 identified extending the service life and optimizing structural : systems of bridges in the United States as two grand challenges in bridge engineering, with the objective of producin...

Liquid rocket engine fluid-cooled combustion chambers

NASA Technical Reports Server (NTRS)

1972-01-01

A monograph on the design and development of fluid cooled combustion chambers for liquid propellant rocket engines is presented. The subjects discussed are (1) regenerative cooling, (2) transpiration cooling, (3) film cooling, (4) structural analysis, (5) chamber reinforcement, and (6) operational problems.

Design procedures for heat-straightening repair : an engineering guide.

DOT National Transportation Integrated Search

1992-12-01

This report summarizes over four years of research on heat-straightening repairs and provides a prototype engineering guide for the application of heat-straightening to bridge structures. It is based on the research results detailed in a companion re...

Using Dedal to share and reuse distributed engineering design information

NASA Technical Reports Server (NTRS)

Baya, Vinod; Baudin, Catherine; Mabogunje, Ade; Das, Aseem; Cannon, David M.; Leifer, Larry J.

1994-01-01

The overall goal of the project is to facilitate the reuse of previous design experience for the maintenance, repair and redesign of artifacts in the electromechanical engineering domain. An engineering team creates information in the form of meeting summaries, project memos, progress reports, engineering notes, spreadsheet calculations and CAD drawings. Design information captured in these media is difficult to reuse because the way design concepts are referred to evolve over the life of a project and because decisions, requirements and structure are interrelated but rarely explicitly linked. Based on protocol analysis of the information seeking behavior of designer's, we defined a language to describe the content and the form of design records and implemented this language in Dedal, a tool for indexing, modeling and retrieving design information. We first describe the approach to indexing and retrieval in Dedal. Next we describe ongoing work in extending Dedal's capabilities to a distributed environment by integrating it with World Wide Web. This will enable members of a design team who are not co-located to share and reuse information.

Improving Legacy Aircraft Systems Through Condition-Based Maintenance: An H-60 Case Study

DTIC Science & Technology

2014-09-01

level functions. These decompositions are equivalent to a detailed design effort in systems engineering. NAMPSOPs have a common architectural structure...Assembly Power Available Spindle Cables No.1 Engine Load Demand Spindle Control Cables Engine Pneumatic Starters Auxiliary Power Unit IRCM FLIR Mission...Analysis Fuel System Main Rotor Head Main Module Main Gear Box Radiator Engine Output Shaft Auxiliary Power Unit Flight Control Cables Tail Landing

Numerical analysis of stiffened shells of revolution. Volume 4: Engineer's program manual for STARS-2S shell theory automated for rotational structures - 2 (statics) digital computer program

NASA Technical Reports Server (NTRS)

Svalbonas, V.; Ogilvie, P.

1973-01-01

The engineering programming information for the digital computer program for analyzing shell structures is presented. The program is designed to permit small changes such as altering the geometry or a table size to fit the specific requirements. Each major subroutine is discussed and the following subjects are included: (1) subroutine description, (2) pertinent engineering symbols and the FORTRAN coded counterparts, (3) subroutine flow chart, and (4) subroutine FORTRAN listing.

The use of participant-observation protocol in an industrial engineering research.

PubMed

Silveira e Silva, Renato da; Sznelwar, Laerte Idal; D'Afonseca e Silva, Victor

2012-01-01

Based on literature, this article aims to present the "participant-observation' research protocol, and its practical application in the industrial engineering field, more specifically within the area of design development, and in the case shown by this article, of interiors' design. The main target is to identify the concept of the method, i.e., from its characteristics to structure a general sense about the subject, so that the protocol can be used in different areas of knowledge, especially those ones which are committed with the scientific research involving the expertise from researchers, and subjective feelings and opinions of the users of an engineering product, and how this knowledge can be benefic for product design, contributing since the earliest stage of design.

QCSEE UTW engine powered-lift acoustic performance

NASA Technical Reports Server (NTRS)

Loeffler, I. J.; Samanich, N. E.; Bloomer, H. E.

1980-01-01

Powered-lift acoustic test of the Quiet Clean Short Haul Experimental Engine (QCSEE) under the wing (UTW) engine are reported. Propulsion systems for two powered-lift concepts were designed, fabricated, and tested. In addition to low noise features, the designs included composite structures, gear-driven fans, digital control, and a variable pitch fan (UTW). The UTW engine was tested in a static ground test facility with wing and flap segments to simulate installation on a short haul transport aircraft of the future. Powered-lift acoustic performance of the UTW engine is compared with that of the previously tested and reported QCSEE over-the-wing (OTW) engine. Both engines were slightly above the noise goal but were significantly below current FAA and modern wide-body jet transport levels. The UTW system in the powered-lift mode was penalized by reflected engine noise from the wing and flap system, while the OTW system was benefitted by a wing noise shielding effect.

Improved guidance for users of the 1993 AASHTO flexible pavement design procedures : LTPP TechBrief

DOT National Transportation Integrated Search

1997-08-01

A key design challenge faced by engineers using the 1993 AASHTO Guide for Design of Pavement Structures (AASHTO Guide) is the determination of appropriate design parameters for the subgrade and pavement materials. The Long-Term Pavement Performance (...

X-33 Attitude Control Using the XRS-2200 Linear Aerospike Engine

NASA Technical Reports Server (NTRS)

Hall, Charles E.; Panossian, Hagop V.

1999-01-01

The Vehicle Control Systems Team at Marshall Space Flight Center, Structures and Dynamics Laboratory, Guidance and Control Systems Division is designing, under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control systems for the X-33 experimental vehicle. Test flights, while suborbital, will achieve sufficient altitudes and Mach numbers to test Single Stage To Orbit, Reusable Launch Vehicle technologies. Ascent flight control phase, the focus of this paper, begins at liftoff and ends at linear aerospike main engine cutoff (MECO). The X-33 attitude control system design is confronted by a myriad of design challenges: a short design cycle, the X-33 incremental test philosophy, the concurrent design philosophy chosen for the X-33 program, and the fact that the attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems. Additionally, however, and of special interest, the use of the linear aerospike engine is a departure from the gimbaled engines traditionally used for thrust vector control (TVC) in launch vehicles and poses certain design challenges. This paper discusses the unique problem of designing the X-33 attitude control system with the linear aerospike engine, requirements development, modeling and analyses that verify the design.

Understanding Biological Regulation Through Synthetic Biology.

PubMed

Bashor, Caleb J; Collins, James J

2018-05-20

Engineering synthetic gene regulatory circuits proceeds through iterative cycles of design, building, and testing. Initial circuit designs must rely on often-incomplete models of regulation established by fields of reductive inquiry-biochemistry and molecular and systems biology. As differences in designed and experimentally observed circuit behavior are inevitably encountered, investigated, and resolved, each turn of the engineering cycle can force a resynthesis in understanding of natural network function. Here, we outline research that uses the process of gene circuit engineering to advance biological discovery. Synthetic gene circuit engineering research has not only refined our understanding of cellular regulation but furnished biologists with a toolkit that can be directed at natural systems to exact precision manipulation of network structure. As we discuss, using circuit engineering to predictively reorganize, rewire, and reconstruct cellular regulation serves as the ultimate means of testing and understanding how cellular phenotype emerges from systems-level network function.

Thermal/structural Tailoring of Engine Blades (T/STAEBL) User's Manual

NASA Technical Reports Server (NTRS)

Brown, K. W.; Clevenger, W. B.; Arel, J. D.

1994-01-01

The Thermal/Structural Tailoring of Engine Blades (T/STAEBL) system is a family of computer programs executed by a control program. The T/STAEBL system performs design optimizations of cooled, hollow turbine blades and vanes. This manual contains an overview of the system, fundamentals of the data block structure, and detailed descriptions of the inputs required by the optimizer. Additionally, the thermal analysis input requirements are described as well as the inputs required to perform a finite element blade vibrations analysis.

NASA Structural Analysis System (NASTRAN)

NASA Technical Reports Server (NTRS)

Purves, L.

1991-01-01

Program aids in structural design of wide range of objects, from high-impact printer parts to turbine engine blades, and fully validated. Since source code included, NASTRAN modified or enhanced for new applications.

Structural dynamics and vibrations of damped, aircraft-type structures

NASA Technical Reports Server (NTRS)

Young, Maurice I.

1992-01-01

Engineering preliminary design methods for approximating and predicting the effects of viscous or equivalent viscous-type damping treatments on the free and forced vibration of lightly damped aircraft-type structures are developed. Similar developments are presented for dynamic hysteresis viscoelastic-type damping treatments. It is shown by both engineering analysis and numerical illustrations that the intermodal coupling of the undamped modes arising from the introduction of damping may be neglected in applying these preliminary design methods, except when dissimilar modes of these lightly damped, complex aircraft-type structures have identical or nearly identical natural frequencies. In such cases, it is shown that a relatively simple, additional interaction calculation between pairs of modes exhibiting this 'modal response' phenomenon suffices in the prediction of interacting modal damping fractions. The accuracy of the methods is shown to be very good to excellent, depending on the normal natural frequency separation of the system modes, thereby permitting a relatively simple preliminary design approach. This approach is shown to be a natural precursor to elaborate finite element, digital computer design computations in evaluating the type, quantity, and location of damping treatment.

Probabilistic Finite Element Analysis & Design Optimization for Structural Designs

NASA Astrophysics Data System (ADS)

Deivanayagam, Arumugam

This study focuses on implementing probabilistic nature of material properties (Kevlar® 49) to the existing deterministic finite element analysis (FEA) of fabric based engine containment system through Monte Carlo simulations (MCS) and implementation of probabilistic analysis in engineering designs through Reliability Based Design Optimization (RBDO). First, the emphasis is on experimental data analysis focusing on probabilistic distribution models which characterize the randomness associated with the experimental data. The material properties of Kevlar® 49 are modeled using experimental data analysis and implemented along with an existing spiral modeling scheme (SMS) and user defined constitutive model (UMAT) for fabric based engine containment simulations in LS-DYNA. MCS of the model are performed to observe the failure pattern and exit velocities of the models. Then the solutions are compared with NASA experimental tests and deterministic results. MCS with probabilistic material data give a good prospective on results rather than a single deterministic simulation results. The next part of research is to implement the probabilistic material properties in engineering designs. The main aim of structural design is to obtain optimal solutions. In any case, in a deterministic optimization problem even though the structures are cost effective, it becomes highly unreliable if the uncertainty that may be associated with the system (material properties, loading etc.) is not represented or considered in the solution process. Reliable and optimal solution can be obtained by performing reliability optimization along with the deterministic optimization, which is RBDO. In RBDO problem formulation, in addition to structural performance constraints, reliability constraints are also considered. This part of research starts with introduction to reliability analysis such as first order reliability analysis, second order reliability analysis followed by simulation technique that are performed to obtain probability of failure and reliability of structures. Next, decoupled RBDO procedure is proposed with a new reliability analysis formulation with sensitivity analysis, which is performed to remove the highly reliable constraints in the RBDO, thereby reducing the computational time and function evaluations. Followed by implementation of the reliability analysis concepts and RBDO in finite element 2D truss problems and a planar beam problem are presented and discussed.

Nucleic Acid Engineering: RNA Following the Trail of DNA.

PubMed

Kim, Hyejin; Park, Yongkuk; Kim, Jieun; Jeong, Jaepil; Han, Sangwoo; Lee, Jae Sung; Lee, Jong Bum

2016-02-08

The self-assembly feature of the naturally occurring biopolymer, DNA, has fascinated researchers in the fields of materials science and bioengineering. With the improved understanding of the chemical and structural nature of DNA, DNA-based constructs have been designed and fabricated from two-dimensional arbitrary shapes to reconfigurable three-dimensional nanodevices. Although DNA has been used successfully as a building block in a finely organized and controlled manner, its applications need to be explored. Hence, with the myriad of biological functions, RNA has recently attracted considerable attention to further the application of nucleic acid-based structures. This Review categorizes different approaches of engineering nucleic acid-based structures and introduces the concepts, principles, and applications of each technique, focusing on how DNA engineering is applied as a guide to RNA engineering.

Engineers and Active Responsibility.

PubMed

Pesch, Udo

2015-08-01

Knowing that technologies are inherently value-laden and systemically interwoven with society, the question is how individual engineers can take up the challenge of accepting the responsibility for their work? This paper will argue that engineers have no institutional structure at the level of society that allows them to recognize, reflect upon, and actively integrate the value-laden character of their designs. Instead, engineers have to tap on the different institutional realms of market, science, and state, making their work a 'hybrid' activity combining elements from the different institutional realms. To deal with this institutional hybridity, engineers develop routines and heuristics in their professional network, which do not allow societal values to be expressed in a satisfactory manner. To allow forms of 'active' responsibility, there have to be so-called 'accountability forums' that guide moral reflections of individual actors. The paper will subsequently look at the methodologies of value-sensitive design (VSD) and constructive technology assessment (CTA) and explore whether and how these methodologies allow engineers to integrate societal values into the design technological artifacts and systems. As VSD and CTA are methodologies that look at the process of technological design, whereas the focus of this paper is on the designer, they can only be used indirectly, namely as frameworks which help to identify the contours of a framework for active responsibility of engineers.

Fatigue in aerostructures--where structural health monitoring can contribute to a complex subject.

PubMed

Boller, Christian; Buderath, Matthias

2007-02-15

An overview of the aircraft design and maintenance process is given with specific emphasis on the fatigue design as well as the phenomenon of the ageing aircraft observed over the life cycle. The different measures taken to guarantee structural integrity along the maintenance process are addressed. The impact of structural health monitoring as a means of possibly revolutionizing the current aircraft structural monitoring and design process is emphasized and comparison is made to jet engines and helicopters, where health monitoring has already found the respective breakthrough.

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 2: Engineering. Volume 3: Costs and schedules

NASA Astrophysics Data System (ADS)

1981-09-01

Engineering design details for the principal systems, system operating modes, site facilities, and structures of an engineering test facility (ETF) of a 200 MWE power plant are presented. The ETF resembles a coal-fired steam power plant in many ways. It is analogous to a conventional plant which has had the coal combustor replaced with the MHD power train. Most of the ETF components are conventional. They can, however, be sized or configured differently or perform additional functions from those in a conventional coal power plant. The boiler not only generates steam, but also performs the functions of heating the MHD oxidant, recovering seed, and controlling emissions.

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Conceptual Design Engineering Report (CDER). Volume 2: Engineering. Volume 3: Costs and schedules

NASA Technical Reports Server (NTRS)

1981-01-01

Engineering design details for the principal systems, system operating modes, site facilities, and structures of an engineering test facility (ETF) of a 200 MWE power plant are presented. The ETF resembles a coal-fired steam power plant in many ways. It is analogous to a conventional plant which has had the coal combustor replaced with the MHD power train. Most of the ETF components are conventional. They can, however, be sized or configured differently or perform additional functions from those in a conventional coal power plant. The boiler not only generates steam, but also performs the functions of heating the MHD oxidant, recovering seed, and controlling emissions.

Structures, performance, benefit, cost study. [gas turbine engines

NASA Technical Reports Server (NTRS)

Feder, E.

1981-01-01

Aircraft engine structures were studied to identify the advanced structural technologies that would provide the most benefits to future aircraft operations. A series of studies identified engine systems with the greatest potential for improvements. Based on these studies, six advanced generic structural concepts were selected and conceptually designed. The benefits of each concept were quantitatively assessed in terms of thrust specific fuel consumption, weight, cost, maintenance cost, fuel burned and direct operating cost plus interest. The probability of success of each concept was also determined. The concepts were ranked and the three most promising were selected for further study which consisted of identifying and comprehensively outlining the advanced technologies required to develop these concepts for aircraft engine application. Analytic, fabrication, and test technology developments are required. The technology programs outlined emphasize the need to provide basic, fundamental understanding of technology to obtain the benefit goals.

Mathematical support for surveying measurements in order to obtain the draft tube three-dimensional model

NASA Astrophysics Data System (ADS)

Gridan, Maria-Roberta; Herban, Sorin; Grecea, Oana

2017-07-01

Nowadays, the engineering companies and contractors are facing challenges never experienced before. They are being charged with - and being held liable for - the health of the structures they create and maintain. To surmount these challenges, engineers need to be able to measure structural movements up to millimetre level accuracy. Accurate and timely information on the status of a structure is highly valuable to engineers. It enables them to compare the real world behaviour of a structure against the design and theoretical models. When empowered by such data, engineers can effectively and cost efficiently measure and maintain the health of vital infrastructure. This paper presents the interpretation of the draft tube topographical measurements in order to obtain its 3D model. Based on the documents made available by the beneficiary and the data obtained in situ, the modernization conclusions were presented.

Engineering aspects of the application of structural materials in the 5 MW-ESS-mercury-target

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

Guttek, B.

1996-06-01

A main problem of the ESS-Hg-target development and the design of the components of its primary Hg-circuit is the choice of structural materials. As designing, calculations and experiments with elected materials take time and are very costy, a preview on their successful application has to be done before as detailed as possible. One aspect on this is to have the knowledge of characteristics values of the structural material candidates under the occuring mechanical and thermal loads, irradiation, corrosion and erosion. Another point is the technology of engineering concerning the manufacturing, welding, surface treatment, and quality control of such parts andmore » components under the demand to reach maximum lifetime.« less

Engineering education as a complex system

NASA Astrophysics Data System (ADS)

Gattie, David K.; Kellam, Nadia N.; Schramski, John R.; Walther, Joachim

2011-12-01

This paper presents a theoretical basis for cultivating engineering education as a complex system that will prepare students to think critically and make decisions with regard to poorly understood, ill-structured issues. Integral to this theoretical basis is a solution space construct developed and presented as a benchmark for evaluating problem-solving orientations that emerge within students' thinking as they progress through an engineering curriculum. It is proposed that the traditional engineering education model, while analytically rigorous, is characterised by properties that, although necessary, are insufficient for preparing students to address complex issues of the twenty-first century. A Synthesis and Design Studio model for engineering education is proposed, which maintains the necessary rigor of analysis within a uniquely complex yet sufficiently structured learning environment.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Technical Reports Server (NTRS)

Monell, Donald W.; Piland, William M.

1999-01-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g. manufacturing and systems operations). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often lead to the inability of assessing critical programmatic and technical issues (e.g., cost risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographically distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across the Agency.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Astrophysics Data System (ADS)

Monell, Donald W.; Piland, William M.

2000-07-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g., manufacturing and systems operations). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often led to the inability of assessing critical programmatic and technical issues (e.g., cost, risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographically distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across the Agency.

Prototype design of a collision protection system for cab car engineers - fabrication and test.

DOT National Transportation Integrated Search

2015-06-01

Advancements in the structural crashworthiness of passenger rail cars now make it possible to preserve the compartmentalized : space occupied by a cab car engineer during a train collision. In order to translate this additional protection into improv...

PEER News

Science.gov Websites

home about peer news events research products laboratories publications nisee b.i.p. members Engineering Services is Hiring Bridge Design and Bridge Construction Engineers 05/16/18 - PEER Research Research Project Highlight: "Dissipative Base Connections for Moment Frame Structures in Airports and

Integrating ergonomics knowledge into business-driven design projects: The shaping of resource constraints in engineering consultancy.

PubMed

Hall-Andersen, Lene Bjerg; Neumann, Patrick; Broberg, Ole

2016-10-17

The integration of ergonomics knowledge into engineering projects leads to both healthier and more efficient workplaces. There is a lack of knowledge about integrating ergonomic knowledge into the design practice in engineering consultancies. This study explores how organizational resources can pose constraints for the integration of ergonomics knowledge into engineering design projects in a business-driven setting, and how ergonomists cope with these resource constraints. An exploratory case study in an engineering consultancy was conducted. A total of 27 participants were interviewed. Data were collected applying semi-structured interviews, observations, and documentary studies. Interviews were transcribed, coded, and categorized into themes. From the analysis five overall themes emerged as major constituents of resource constraints: 1) maximizing project revenue, 2) payment for ergonomics services, 3) value of ergonomic services, 4) role of the client, and 5) coping strategies to overcome resource constraints. We hypothesize that resource constraints were shaped due to sub-optimization of costs in design projects. The economical contribution of ergonomics measures was not evaluated in the entire life cycle of a designed workplace. Coping strategies included teaming up with engineering designers in the sales process or creating an alliance with ergonomists in the client organization.

The 7.5K lbf thrust engine preliminary design for Orbit Transfer Vehicle

NASA Technical Reports Server (NTRS)

Hayden, Warren R.; Sabiers, Ralph; Schneider, Judy

1994-01-01

This document summarizes the preliminary design of the Aerojet version of the Orbit Transfer Vehicle main engine. The concept of a 7500 lbf thrust LO2/GH2 engine using the dual expander cycle for optimum efficiency is validated through power balance and thermal calculations. The engine is capable of 10:1 throttling from a nominal 2000 psia to a 200 psia chamber pressure. Reservations are detailed on the feasibility of a tank head start, but the design incorporates low speed turbopumps to mitigate the problem. The mechanically separate high speed turbopumps use hydrostatic bearings to meet engine life requirements, and operate at sub-critical speed for better throttling ability. All components were successfully packaged in the restricted envelope set by the clearances for the extendible/retractable nozzle. Gimbal design uses an innovative primary and engine out gimbal system to meet the +/- 20 deg gimbal requirement. The hydrogen regenerator and LOX/GH2 heat exchanger uses the Aerojet platelet structures approach for a highly compact component design. The extendible/retractable nozzle assembly uses an electric motor driven jack-screw design and a one segment carbon-carbon or silicide coated columbium nozzle with an area ratio, when extended, of 1430:1. A reliability analysis and risk assessment concludes the report.

Analysis of Stainless Steel Sandwich Panels with a Metal Foam Core for Lightweight Fan Blade Design

NASA Technical Reports Server (NTRS)

Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

2004-01-01

The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. The present study investigates the use of a sandwich foam fan blade mae up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The resulting structures possesses a high stiffness while being lighter than a similar solid construction. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of sandwich structure for a fan blade application. A vibration analysis for natural frequencies and a detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of kin thickness and core volume are presented with a comparison to a solid titanium blade.

The MSFC Collaborative Engineering Process for Preliminary Design and Concept Definition Studies

NASA Technical Reports Server (NTRS)

Mulqueen, Jack; Jones, David; Hopkins, Randy

2011-01-01

This paper describes a collaborative engineering process developed by the Marshall Space Flight Center's Advanced Concepts Office for performing rapid preliminary design and mission concept definition studies for potential future NASA missions. The process has been developed and demonstrated for a broad range of mission studies including human space exploration missions, space transportation system studies and in-space science missions. The paper will describe the design team structure and specialized analytical tools that have been developed to enable a unique rapid design process. The collaborative engineering process consists of integrated analysis approach for mission definition, vehicle definition and system engineering. The relevance of the collaborative process elements to the standard NASA NPR 7120.1 system engineering process will be demonstrated. The study definition process flow for each study discipline will be will be outlined beginning with the study planning process, followed by definition of ground rules and assumptions, definition of study trades, mission analysis and subsystem analyses leading to a standardized set of mission concept study products. The flexibility of the collaborative engineering design process to accommodate a wide range of study objectives from technology definition and requirements definition to preliminary design studies will be addressed. The paper will also describe the applicability of the collaborative engineering process to include an integrated systems analysis approach for evaluating the functional requirements of evolving system technologies and capabilities needed to meet the needs of future NASA programs.

A design strategy for the use of vortex generators to manage inlet-engine distortion using computational fluid dynamics

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Levy, Ralph

1991-01-01

A reduced Navier-Stokes solution technique was successfully used to design vortex generator installations for the purpose of minimizing engine face distortion by restructuring the development of secondary flow that is induced in typical 3-D curved inlet ducts. The results indicate that there exists an optimum axial location for this installation of corotating vortex generators, and within this configuration, there exists a maximum spacing between generator blades above which the engine face distortion increases rapidly. Installed vortex generator performance, as measured by engine face circumferential distortion descriptors, is sensitive to Reynolds number and thereby the generator scale, i.e., the ratio of generator blade height to local boundary layer thickness. Installations of corotating vortex generators work well in terms of minimizing engine face distortion within a limited range of generator scales. Hence, the design of vortex generator installations is a point design, and all other conditions are off design. In general, the loss levels associated with a properly designed vortex generator installation are very small; thus, they represent a very good method to manage engine face distortion. This study also showed that the vortex strength, generator scale, and secondary flow field structure have a complicated and interrelated influence over engine face distortion, over and above the influence of the initial arrangement of generators.

An application of holographic interferometry for dynamic vibration analysis of a jet engine turbine compressor rotor

NASA Astrophysics Data System (ADS)

Fein, Howard

2003-09-01

Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under dynamic stress. Specialized variations of this technology have also been applied to define dynamic and vibration related structural behavior. Such applications of holographic technique offer some of the most effective methods of modal and dynamic analysis available. Real-time dynamic testing of the modal and mechanical behavior of jet engine turbine, rotor, vane, and compressor structures has always required advanced instrumentation for data collection in either simulated flight operation test or computer-based modeling and simulations. Advanced optical holography techniques are alternate methods which result in actual full-field behavioral data in a noninvasive, noncontact environment. These methods offer significant insight in both the development and subsequent operational test and modeling of advanced jet engine turbine and compressor rotor structures and their integration with total vehicle system dynamics. Structures and materials can be analyzed with very low amplitude excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural and behavioral models. Holographic Interferometry offers a powerful tool to aid in the developmental engineering of turbine rotor and compressor structures for high stress applications. Aircraft engine applications in particular most consider operational environments where extremes in vibration and impulsive as well as continuous mechanical stress can affect both operation and structural stability. These considerations present ideal requisites for analysis using advanced holographic methods in the initial design and test of turbine rotor components. Holographic techniques are nondestructive, real-time, and definitive in allowing the identification of vibrational modes, displacements, and motion geometries. Such information can be crucial to the determination of mechanical configurations and designs as well as critical operational parameters of turbine structural components or unit turbine components fabricated from advanced and exotic new materials or using new fabrication methods. Anomalous behavioral characteristics can be directly related to hidden structural or mounting anomalies and defects.

Channeled Scaffolds for Engineering Myocardium with Mechanical Stimulation

PubMed Central

Zhang, Ting; Wan, Leo Q.; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

2011-01-01

The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) are critically important for engineering functional myocardial tissue. We report the development of chitosan-collagen scaffolds with micro-pores and an array of parallel channels (~200 μm in diameter) that were specifically designed for cardiac tissue engineering with mechanical stimulation. The scaffolds were designed to have the structural and mechanical properties similar to those of the native human heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom-designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1–2 mm thick) consisted of metabolically active cells and started to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stresses promoted cell alignment, elongation, and the expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. PMID:22081518

Channelled scaffolds for engineering myocardium with mechanical stimulation.

PubMed

Zhang, Ting; Wan, Leo Q; Xiong, Zhuo; Marsano, Anna; Maidhof, Robert; Park, Miri; Yan, Yongnian; Vunjak-Novakovic, Gordana

2012-10-01

The characteristics of the matrix (composition, structure, mechanical properties) and external culture environment (pulsatile perfusion, physical stimulation) of the heart are important characteristics in the engineering of functional myocardial tissue. This study reports on the development of chitosan-collagen scaffolds with micropores and an array of parallel channels (~ 200 µm in diameter) that were specifically designed for cardiac tissue engineering using mechanical stimulation. The scaffolds were designed to have similar structural and mechanical properties of those of native heart matrix. Scaffolds were seeded with neonatal rat heart cells and subjected to dynamic tensile stretch using a custom designed bioreactor. The channels enhanced oxygen transport and facilitated the establishment of cell connections within the construct. The myocardial patches (14 mm in diameter, 1-2 mm thick) consisted of metabolically active cells that began to contract synchronously after 3 days of culture. Mechanical stimulation with high tensile stress promoted cell alignment, elongation, and expression of connexin-43 (Cx-43). This study confirms the importance of scaffold design and mechanical stimulation for the formation of contractile cardiac constructs. Copyright © 2011 John Wiley & Sons, Ltd.

Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics

PubMed Central

Grindy, Scott C.; Learsch, Robert; Mozhdehi, Davoud; Cheng, Jing; Barrett, Devin G.; Guan, Zhibin; Messersmith, Phillip B.; Holten-Andersen, Niels

2015-01-01

In conventional polymer materials, mechanical performance is traditionally engineered via material structure, using motifs such as polymer molecular weight, polymer branching, or copolymer-block design1. Here, by means of a model system of 4-arm poly(ethylene glycol) hydrogels crosslinked with multiple, kinetically distinct dynamic metal-ligand coordinate complexes, we show that polymer materials with decoupled spatial structure and mechanical performance can be designed. By tuning the relative concentration of two types of metal-ligand crosslinks, we demonstrate control over the material’s mechanical hierarchy of energy-dissipating modes under dynamic mechanical loading, and therefore the ability to engineer a priori the viscoelastic properties of these materials by controlling the types of crosslinks rather than by modifying the polymer itself. This strategy to decouple material mechanics from structure may inform the design of soft materials for use in complex mechanical environments. PMID:26322715

Design Principles for the Atomic and Electronic Structure of Halide Perovskite Photovoltaic Materials: Insights from Computation.

PubMed

Berger, Robert F

2018-02-09

In the current decade, perovskite solar cell research has emerged as a remarkably active, promising, and rapidly developing field. Alongside breakthroughs in synthesis and device engineering, halide perovskite photovoltaic materials have been the subject of predictive and explanatory computational work. In this Minireview, we focus on a subset of this computation: density functional theory (DFT)-based work highlighting the ways in which the electronic structure and band gap of this class of materials can be tuned via changes in atomic structure. We distill this body of computational literature into a set of underlying design principles for the band gap engineering of these materials, and rationalize these principles from the viewpoint of band-edge orbital character. We hope that this perspective provides guidance and insight toward the rational design and continued improvement of perovskite photovoltaics. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Parallel-Vector Algorithm For Rapid Structural Anlysis

NASA Technical Reports Server (NTRS)

Agarwal, Tarun R.; Nguyen, Duc T.; Storaasli, Olaf O.

1993-01-01

New algorithm developed to overcome deficiency of skyline storage scheme by use of variable-band storage scheme. Exploits both parallel and vector capabilities of modern high-performance computers. Gives engineers and designers opportunity to include more design variables and constraints during optimization of structures. Enables use of more refined finite-element meshes to obtain improved understanding of complex behaviors of aerospace structures leading to better, safer designs. Not only attractive for current supercomputers but also for next generation of shared-memory supercomputers.

Engine isolation for structural-borne interior noise reduction in a general aviation aircraft

NASA Technical Reports Server (NTRS)

Unruh, J. F.; Scheidt, D. C.

1981-01-01

Engine vibration isolation for structural-borne interior noise reduction is investigated. A laboratory based test procedure to simulate engine induced structure-borne noise transmission, the testing of a range of candidate isolators for relative performance data, and the development of an analytical model of the transmission phenomena for isolator design evaluation are addressed. The isolator relative performance test data show that the elastomeric isolators do not appear to operate as single degree of freedom systems with respect to noise isolation. Noise isolation beyond 150 Hz levels off and begins to decrease somewhat above 600 Hz. Coupled analytical and empirical models were used to study the structure-borne noise transmission phenomena. Correlation of predicted results with measured data show that (1) the modeling procedures are reasonably accurate for isolator design evaluation, (2) the frequency dependent properties of the isolators must be included in the model if reasonably accurate noise prediction beyond 150 Hz is desired. The experimental and analytical studies were carried out in the frequency range from 10 Hz to 1000 Hz.

Artistic and Industrial Institutions in Russian Education Structure in First Quarter of XXth Century

NASA Astrophysics Data System (ADS)

Chernyh, D. G.

2017-11-01

The article tells about the formation of Russian design education in the XXth century. It focuses on the peculiar features and causes of its insufficient effectiveness in the historical context. It studies the dynamics of changes in the priorities related to the artistic and industrial education in Russia and the connection of these processes with socio-political transformations. The article identifies the role of constructivist artists in the formation and approbation of advanced design-engineering techniques. It emphasizes the interdisciplinary essence of the profession of a designer as a special kind of design activities, its organizing, consolidating and progressive origin in the sphere of industrial production and carrying out interdisciplinary studies. It discloses the essence of a new “engineer-artist” profession. It briefly describes the influence of the fundamental principle of design - projectivity, on engineering and design disciplines when the interaction of an artist, an engineer and an architect is achieved on the basis of design, arrangement and inventive art as well as production organization where science and technology form the basis for creative work.

Seismic Analysis of Intake Towers

DTIC Science & Technology

1982-10-01

Experiment Station (WES) under the sponsorship of the Directorate of Civil Works of the Office, Chief of Engineers, U. S. Army. The work was funded under...the structural capacity of the intake S,-tower are contained in Engineer Technical Letter (ETL) 1110-2-265 " Civil Systems Incorporated, "Dynamic...Berkeley, Calif. " ___ 1975. "Earthquake Resistant Design of Intake-Outlet Towers," Journal of the Structural Division_ American Society of Civil

Computational smart polymer design based on elastin protein mutability.

PubMed

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

2017-05-01

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

ADVANCED SEISMIC BASE ISOLATION METHODS FOR MODULAR REACTORS

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

E. Blanford; E. Keldrauk; M. Laufer

2010-09-20

Advanced technologies for structural design and construction have the potential for major impact not only on nuclear power plant construction time and cost, but also on the design process and on the safety, security and reliability of next generation of nuclear power plants. In future Generation IV (Gen IV) reactors, structural and seismic design should be much more closely integrated with the design of nuclear and industrial safety systems, physical security systems, and international safeguards systems. Overall reliability will be increased, through the use of replaceable and modular equipment, and through design to facilitate on-line monitoring, in-service inspection, maintenance, replacement,more » and decommissioning. Economics will also receive high design priority, through integrated engineering efforts to optimize building arrangements to minimize building heights and footprints. Finally, the licensing approach will be transformed by becoming increasingly performance based and technology neutral, using best-estimate simulation methods with uncertainty and margin quantification. In this context, two structural engineering technologies, seismic base isolation and modular steel-plate/concrete composite structural walls, are investigated. These technologies have major potential to (1) enable standardized reactor designs to be deployed across a wider range of sites, (2) reduce the impact of uncertainties related to site-specific seismic conditions, and (3) alleviate reactor equipment qualification requirements. For Gen IV reactors the potential for deliberate crashes of large aircraft must also be considered in design. This report concludes that base-isolated structures should be decoupled from the reactor external event exclusion system. As an example, a scoping analysis is performed for a rectangular, decoupled external event shell designed as a grillage. This report also reviews modular construction technology, particularly steel-plate/concrete construction using factory prefabricated structural modules, for application to external event shell and base isolated structures.« less

Creating meaningful learning experiences: Understanding students' perspectives of engineering design

NASA Astrophysics Data System (ADS)

Aleong, Richard James Chung Mun

There is a societal need for design education to prepare holistic engineers with the knowledge, skills, and attitudes to innovate and compete globally. Design skills are paramount to the espoused values of higher education, as institutions of higher learning strive to develop in students the cognitive abilities of critical thinking, problem solving, and creativity. To meet these interests from industry and academia, it is important to advance the teaching and learning of engineering design. This research aims to understand how engineering students learn and think about design, as a way for engineering educators to optimize instructional practice and curriculum development. Qualitative research methodology was used to investigate the meaning that engineering students' ascribe to engineering design. The recruitment of participants and corresponding collection of data occurred in two phases using two different data collection techniques. The first phase involved the distribution of a one-time online questionnaire to all first year, third year, and fourth year undergraduate engineering students at three Canadian Universities. After the questionnaire, students were asked if they would be willing to participate in the second phase of data collection consisting of a personal interview. A total of ten students participated in interviews. Qualitative data analysis procedures were conducted on students' responses from the questionnaire and interviews. The data analysis process consisted of two phases: a descriptive phase to code and categorize the data, followed by an interpretative phase to generate further meaning and relationships. The research findings present a conceptual understanding of students' descriptions about engineering design, structured within two educational orientations: a learning studies orientation and a curriculum studies orientation. The learning studies orientation captured three themes of students' understanding of engineering design: awareness, relevance, and transfer. With this framework of student learning, engineering educators can enhance learning experiences by engaging all three levels of students' understanding. The curriculum studies orientation applied the three holistic elements of curriculum---subject matter, society, and the individual---to conceptualize design considerations for engineering curriculum and teaching practice. This research supports the characterization of students' learning experiences to help educators and students optimize their teaching and learning of design education.

Biological materials by design.

PubMed

Qin, Zhao; Dimas, Leon; Adler, David; Bratzel, Graham; Buehler, Markus J

2014-02-19

In this topical review we discuss recent advances in the use of physical insight into the way biological materials function, to design novel engineered materials 'from scratch', or from the level of fundamental building blocks upwards and by using computational multiscale methods that link chemistry to material function. We present studies that connect advances in multiscale hierarchical material structuring with material synthesis and testing, review case studies of wood and other biological materials, and illustrate how engineered fiber composites and bulk materials are designed, modeled, and then synthesized and tested experimentally. The integration of experiment and simulation in multiscale design opens new avenues to explore the physics of materials from a fundamental perspective, and using complementary strengths from models and empirical techniques. Recent developments in this field illustrate a new paradigm by which complex material functionality is achieved through hierarchical structuring in spite of simple material constituents.

Wind/Tornado Guidelines Study

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

Ng, D.S.; Holman, G.S.

1991-10-01

This report documents the strategy employed to develop recommended wind/tornado hazard design guidelines for a New Production Reactor (NRP) currently planned for either the Idaho National Engineering Laboratory (INEL) or the Savannah River (SR) site. The Wind/Tornado Working Group (WTWG), comprising six nationally recognized experts in structural engineering, wind engineering, and meteorology, formulated an independent set of guidelines based on site-specific wind/tornado hazard curves and state-of-the-art tornado missile technology. The basic philosophy was to select realistic wind and missile load specifications, and to meet performance goals by applying conservative structural response evaluation and acceptance criteria. Simplified probabilistic risk analyses (PRAs)more » for wind speeds and missile impact were performed to estimate annual damage risk frequencies for both the INEL and SR sites. These PRAs indicate that the guidelines will lead to facilities that meet the US Department of Energy (DOE) design requirements and that the Nuclear Regulatory Commission guidelines adopted by the DOE for design are adequate to meet the NPR safety goals.« less

Status of advanced orbital transfer propulsion

NASA Technical Reports Server (NTRS)

Cooper, L. P.

1985-01-01

A new Orbital Transfer Vehicle (OTV) propulsion system that will be used in conjunction with the Space Shuttle, Space Station and Orbit Maneuvering Vehicle is discussed. The OTV will transfer men, large space structures and conventional payloads between low Earth and higher energy orbits. Space probes carried by the OTV will continue the exploration of the solar system. When lunar bases are established, the OTV will be their transportation link to Earth. Critical engine design considerations based upon the need for low cost payload delivery, space basing, reusability, aeroassist maneuvering, low g transfers of large space structures and man rating are described. The importance of each of these to propulsion design is addressed. Specific propulsion requirements discussed are: (1) high performance H2/O2 engine; (2) multiple engine configurations totalling no more than 15,000 lbf thrust 15 to 20 hr life; (3) space maintainable modular design; (4) health monitoring capability; and (5) safety and mission success with backup auxiliary propulsion.

Aeronautics Technology Possibilities for 2000: Report of a Workshop

NASA Technical Reports Server (NTRS)

1984-01-01

Topics discussed include: Aerodynamics; Propulsion; Structural Analysis and Design Technology; Materials for Structural Members, Propulsion Systems, and Subsystems; Guidance, Navigation, and Control; Computer and Information Technology; Human Factors Engineering; Systems Integration.

Linear solutions to metamaterial volume hologram design using a variational approach.

PubMed

Marks, Daniel L; Smith, David R

2018-04-01

Multiplex volume holograms are conventionally constructed by the repeated exposure of a photosensitive medium to a sequence of external fields, each field typically being the superposition of a reference wave that reconstructs the hologram and the other being a desired signal wave. Because there are no sources of radiation internal to the hologram, the pattern of material modulation is limited to the solutions to Helmholtz's equation in the medium. If the three-dimensional structure of the medium could be engineered at each point rather than limited to the patterns produced by standing waves, more versatile structures may result that can overcome the typical limitations to hologram dynamic range imposed by sequentially superimposing holograms. Metamaterial structures and other synthetic electromagnetic materials offer the possibility of achieving high medium contrast engineered at the subwavelength scale. By posing the multiplex volume holography problem as a linear medium design problem, we explore the potential improvements that such engineered synthetic media may provide over conventional multiplex volume holograms.

Deconvolution of the role of metal and pH in metal coordinating polymers

NASA Astrophysics Data System (ADS)

Cazzell, Seth; Holten-Andersen, Niels

Nature uses metal binding amino acids to engineer both mechanical properties and structural functionality. Some examples of this metal binding behavior can be found in both mussel foot protein and DNA binding protein. The mussel byssal thread contains reversible intermolecular protein-metal bonds, allowing it to withstand harsh intertidal environments. Zinc fingers form intramolecular protein-metal bonds to stabilize the tertiary structure of DNA binding proteins, allowing specific structural functionality. Inspired by both these metal-binding materials, we present mechanical and spectroscopic characterization of a model polymer system, designed to mimic this bonding. Through these studies, we are able to answer fundamental polymer physics questions, such as the role of pH and metal to ligand ratio, illuminating both the macroscopic and microscopic material behavior. These understandings further bio-inspired engineering techniques that are used to design viscoelastic soft materials. I was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

How Differences in Interactions Affect Learning and Development of Design Expertise in the Context of Biomedical Engineering Design

ERIC Educational Resources Information Center

Svihla, Vanessa Lynn

2009-01-01

Authentic design commonly involves teams of designers collaborating on ill-structured problems over extended time periods. Nonetheless, design has been studied extensively in sequestered settings, limiting our understanding of design as process and especially of learning design process. This study addresses potential shortcomings of such studies…

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1991-01-01

This report summarizes work performed in support of the development and demonstration of a structural ceramic technology for automotive gas turbine engines. The AGT101 regenerated gas turbine engine developed under the previous DOE/NASA Advanced Gas Turbine (AGT) program is being utilized for verification testing of the durability of next-generation ceramic components and their suitability for service at reference powertrain design conditions. Topics covered in this report include ceramic processing definition and refinement, design improvements to the test bed engine and test rigs, and design methodologies related to ceramic impact and fracture mechanisms. Appendices include reports by ATTAP subcontractors addressing the development of silicon nitride and silicon carbide families of materials and processes.

Research and development activities in unified control-structure modeling and design

NASA Technical Reports Server (NTRS)

Nayak, A. P.

1985-01-01

Results of work sponsored by JPL and other organizations to develop a unified control/structures modeling and design capability for large space structures is presented. Recent analytical results are presented to demonstrate the significant interdependence between structural and control properties. A new design methodology is suggested in which the structure, material properties, dynamic model and control design are all optimized simultaneously. The development of a methodology for global design optimization is recommended as a long term goal. It is suggested that this methodology should be incorporated into computer aided engineering programs, which eventually will be supplemented by an expert system to aid design optimization. Recommendations are also presented for near term research activities at JPL. The key recommendation is to continue the development of integrated dynamic modeling/control design techniques, with special attention given to the development of structural models specially tailored to support design.

Minimalist design of water-soluble cross-[beta] architecture

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

Biancalana, Matthew; Makabe, Koki; Koide, Shohei

Demonstrated successes of protein design and engineering suggest significant potential to produce diverse protein architectures and assemblies beyond those found in nature. Here, we describe a new class of synthetic protein architecture through the successful design and atomic structures of water-soluble cross-{beta} proteins. The cross-{beta} motif is formed from the lamination of successive {beta}-sheet layers, and it is abundantly observed in the core of insoluble amyloid fibrils associated with protein-misfolding diseases. Despite its prominence, cross-{beta} has been designed only in the context of insoluble aggregates of peptides or proteins. Cross-{beta}'s recalcitrance to protein engineering and conspicuous absence among the knownmore » atomic structures of natural proteins thus makes it a challenging target for design in a water-soluble form. Through comparative analysis of the cross-{beta} structures of fibril-forming peptides, we identified rows of hydrophobic residues ('ladders') running across {beta}-strands of each {beta}-sheet layer as a minimal component of the cross-{beta} motif. Grafting a single ladder of hydrophobic residues designed from the Alzheimer's amyloid-{beta} peptide onto a large {beta}-sheet protein formed a dimeric protein with a cross-{beta} architecture that remained water-soluble, as revealed by solution analysis and x-ray crystal structures. These results demonstrate that the cross-{beta} motif is a stable architecture in water-soluble polypeptides and can be readily designed. Our results provide a new route for accessing the cross-{beta} structure and expanding the scope of protein design.« less

Minimalist design of water-soluble cross-beta architecture.

PubMed

Biancalana, Matthew; Makabe, Koki; Koide, Shohei

2010-02-23

Demonstrated successes of protein design and engineering suggest significant potential to produce diverse protein architectures and assemblies beyond those found in nature. Here, we describe a new class of synthetic protein architecture through the successful design and atomic structures of water-soluble cross-beta proteins. The cross-beta motif is formed from the lamination of successive beta-sheet layers, and it is abundantly observed in the core of insoluble amyloid fibrils associated with protein-misfolding diseases. Despite its prominence, cross-beta has been designed only in the context of insoluble aggregates of peptides or proteins. Cross-beta's recalcitrance to protein engineering and conspicuous absence among the known atomic structures of natural proteins thus makes it a challenging target for design in a water-soluble form. Through comparative analysis of the cross-beta structures of fibril-forming peptides, we identified rows of hydrophobic residues ("ladders") running across beta-strands of each beta-sheet layer as a minimal component of the cross-beta motif. Grafting a single ladder of hydrophobic residues designed from the Alzheimer's amyloid-beta peptide onto a large beta-sheet protein formed a dimeric protein with a cross-beta architecture that remained water-soluble, as revealed by solution analysis and x-ray crystal structures. These results demonstrate that the cross-beta motif is a stable architecture in water-soluble polypeptides and can be readily designed. Our results provide a new route for accessing the cross-beta structure and expanding the scope of protein design.

Designing Extraterrestrial Plant Growth Habitats With Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2001-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Designing Extraterrestrial Plant Growth Habitats with Low Pressure Atmospheres

NASA Technical Reports Server (NTRS)

Corey, Kenneth A.

2002-01-01

In-situ resource utilization, provision of human life support requirements by bioregenerative methods, and engineering constraints for construction and deployment of plant growth structures on the surface of Mars all suggest the need for plant growth studies at hypobaric pressures. Past work demonstrated that plants will likely tolerate and grow at pressures at or below 10 kPa. Based upon this premise, concepts are developed for the design of reduced pressure atmospheres in lightweight, inflatable structures for plant growth systems on Mars with the goals of maximizing design simplicity and the use of local resources. A modular pod design is proposed as it could be integrated with large-scale production systems. Atmospheric modification of pod clusters would be based upon a pulse and scrub system using mass flow methods for atmospheric transport. A specific modification and control scenario is developed for a lettuce pod to illustrate the dynamics of carbon dioxide and oxygen exchange within a pod. Considerations of minimal atmospheric crop requirements will aid in the development of engineering designs and strategies for extraterrestrial plant growth structures that employ rarefied atmospheres.

Refractive index engineering of high performance coupler for compact photonic integrated circuits

NASA Astrophysics Data System (ADS)

Liu, Lu; Zhou, Zhiping

2017-04-01

High performance couplers are highly desired in many applications, but the design is limited by nearly unchangeable material refractive index. To tackle this issue, refractive index engineering method is investigated, which can be realized by subwavelength grating. Subwavelength gratings are periodical structures with pitches small enough to locally synthesize the refractive index of photonic waveguides, which allows direct control of optical profile as well as easier fabrication process. This review provides an introduction to the basics of subwavelength structures and pay special attention to the design strategies of some representative examples of subwavelength grating devices, including: edge couplers, fiber-chip grating couplers, directional couplers and multimode interference couplers. Benefited from the subwavelength grating which can engineer the refractive index as well as birefringence and dispersion, these devices show better performance when compared to their conventional counterparts.

Seonah Kim, Ph.D. | NREL

Science.gov Websites

lignocellulosic biomass enzymes Design of new catalysts for vapor phase upgrading of biomass pyrolysis Enzymatic Engineering for Continuous Hydrocarbon Fuel Production (PI) Computational Pyrolysis Consortium Zeolite design Celluase enzyme structure-function relationships to design enhanced cellulose systems Catalyst

The designer of the 90's: A live demonstration

NASA Technical Reports Server (NTRS)

Green, Tommy L.; Jordan, Basil M., Jr.; Oglesby, Timothy L.

1989-01-01

A survey of design tools to be used by the aircraft designer is given. Structural reliability, maintainability, cost and predictability, and acoustics expert systems are discussed, as well as scheduling, drawing, engineering systems, sizing functions, and standard parts and materials data bases.

Toward high-resolution computational design of helical membrane protein structure and function

PubMed Central

Barth, Patrick; Senes, Alessandro

2016-01-01

The computational design of α-helical membrane proteins is still in its infancy but has made important progress. De novo design has produced stable, specific and active minimalistic oligomeric systems. Computational re-engineering can improve stability and modulate the function of natural membrane proteins. Currently, the major hurdle for the field is not computational, but the experimental characterization of the designs. The emergence of new structural methods for membrane proteins will accelerate progress PMID:27273630

An integrated approach to engineering curricula improvement with multi-objective decision modeling and linear programming

NASA Astrophysics Data System (ADS)

Shea, John E.

The structure of engineering curricula currently in place at most colleges and universities has existed since the early 1950's, and reflects an historical emphasis on a solid foundation in math, science, and engineering science. However, there is often not a close match between elements of the traditional engineering education, and the skill sets that graduates need to possess for success in the industrial environment. Considerable progress has been made to restructure engineering courses and curricula. What is lacking, however, are tools and methodologies that incorporate the many dimensions of college courses, and how they are structured to form a curriculum. If curriculum changes are to be made, the first objective must be to determine what knowledge and skills engineering graduates need to possess. To accomplish this, a set of engineering competencies was developed from existing literature, and used in the development of a comprehensive mail survey of alumni, employers, students and faculty. Respondents proposed some changes to the topics in the curriculum and recommended that work to improve the curriculum be focused on communication, problem solving and people skills. The process of designing a curriculum is similar to engineering design, with requirements that must be met, and objectives that must be optimized. From this similarity came the idea for developing a linear, additive, multi-objective model that identifies the objectives that must be considered when designing a curriculum, and contains the mathematical relationships necessary to quantify the value of a specific alternative. The model incorporates the three primary objectives of engineering topics, skills, and curriculum design principles and uses data from the survey. It was used to design new courses, to evaluate various curricula alternatives, and to conduct sensitivity analysis to better understand their differences. Using the multi-objective model to identify the highest scoring curriculum from a catalog of courses is difficult because of the many factors being considered. To assist this process, the multi-objective model and the curriculum requirements were incorporated in a linear program to select the "optimum" curriculum. The application of this tool was also beneficial in identifying the active constraints that limit curriculum development and content.

Hyper-X Engine Testing in the NASA Langley 8-Foot High Temperature Tunnel

NASA Technical Reports Server (NTRS)

Huebner, Lawrence D.; Rock, Kenneth E.; Witte, David W.; Ruf, Edward G.; Andrews, Earl H., Jr.

2000-01-01

Airframe-integrated scramjet engine tests have 8 completed at Mach 7 in the NASA Langley 8-Foot High Temperature Tunnel under the Hyper-X program. These tests provided critical engine data as well as design and database verification for the Mach 7 flight tests of the Hyper-X research vehicle (X-43), which will provide the first-ever airframe- integrated scramjet flight data. The first model tested was the Hyper-X Engine Model (HXEM), and the second was the Hyper-X Flight Engine (HXFE). The HXEM, a partial-width, full-height engine that is mounted on an airframe structure to simulate the forebody features of the X-43, was tested to provide data linking flowpath development databases to the complete airframe-integrated three-dimensional flight configuration and to isolate effects of ground testing conditions and techniques. The HXFE, an exact geometric representation of the X-43 scramjet engine mounted on an airframe structure that duplicates the entire three-dimensional propulsion flowpath from the vehicle leading edge to the vehicle base, was tested to verify the complete design as it will be flight tested. This paper presents an overview of these two tests, their importance to the Hyper-X program, and the significance of their contribution to scramjet database development.

Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems, Phase II. Part 3; Material Model Development and Simulation of Experiments

NASA Technical Reports Server (NTRS)

Simmons, J.; Erlich, D.; Shockey, D.

2009-01-01

A team consisting of Arizona State University, Honeywell Engines, Systems & Services, the National Aeronautics and Space Administration Glenn Research Center, and SRI International collaborated to develop computational models and verification testing for designing and evaluating turbine engine fan blade fabric containment structures. This research was conducted under the Federal Aviation Administration Airworthiness Assurance Center of Excellence and was sponsored by the Aircraft Catastrophic Failure Prevention Program. The research was directed toward improving the modeling of a turbine engine fabric containment structure for an engine blade-out containment demonstration test required for certification of aircraft engines. The research conducted in Phase II began a new level of capability to design and develop fan blade containment systems for turbine engines. Significant progress was made in three areas: (1) further development of the ballistic fabric model to increase confidence and robustness in the material models for the Kevlar(TradeName) and Zylon(TradeName) material models developed in Phase I, (2) the capability was improved for finite element modeling of multiple layers of fabric using multiple layers of shell elements, and (3) large-scale simulations were performed. This report concentrates on the material model development and simulations of the impact tests.

Thermal structures: Four decades of progress

NASA Technical Reports Server (NTRS)

Thornton, Earl A.

1990-01-01

Since the first supersonic flight in October 1947, the United States has designed, developed and flown flight vehicles within increasingly severe aerothermal environments. Over this period, major advances in engineering capabilities have occurred that will enable the design of thermal structures for high speed flight vehicles in the twenty-first century. Progress in thermal-structures is surveyed for the last four decades to provide a historical perspective for future efforts.

Design of 3D simulation engine for oilfield safety training

NASA Astrophysics Data System (ADS)

Li, Hua-Ming; Kang, Bao-Sheng

2015-03-01

Aiming at the demand for rapid custom development of 3D simulation system for oilfield safety training, this paper designs and implements a 3D simulation engine based on script-driven method, multi-layer structure, pre-defined entity objects and high-level tools such as scene editor, script editor, program loader. A scripting language been defined to control the system's progress, events and operating results. Training teacher can use this engine to edit 3D virtual scenes, set the properties of entity objects, define the logic script of task, and produce a 3D simulation training system without any skills of programming. Through expanding entity class, this engine can be quickly applied to other virtual training areas.

Professional development of Russian HEIs' management and faculty in CDIO standards application

NASA Astrophysics Data System (ADS)

Chuchalin, Alexander; Malmqvist, Johan; Tayurskaya, Marina

2016-07-01

The paper presents the approach to complex training of managers and faculty staff for system modernisation of Russian engineering education. As a methodological basis of design and implementation of the faculty development programme, the CDIO (Conceive-Design-Implement-Operate) Approach was chosen due to compliance of its concept to the purposes and tasks of engineering education development in Russia. The authors describe the structure, the content and implementation technology of the programme designed by Tomsk Polytechnic University and Skolkovo Institute of Science and Technology with the assistance of Chalmers University of Technology and KTH Royal Institute of Technology and other members of the CDIO Initiative. The programme evaluation based on the questionnaire results showed that the programme content is relevant, has high practical value and high level of novelty for all categories of participants. Therefore, the CDIO approach was recommended for implementation to improve various elements of the engineering programme such as learning outcomes, content and structure, teaching, learning and assessment methods. Besides, the feedback results obtained through programme participants' survey contribute to identification of problems preventing development of engineering education in Russia and thus serve as milestones for further development of the programme.

Present capabilities and future requirements for computer-aided geometric modeling in the design and manufacture of gas turbine

NASA Technical Reports Server (NTRS)

Caille, E.; Propen, M.; Hoffman, A.

1984-01-01

Gas turbine engine design requires the ability to rapidly develop complex structures which are subject to severe thermal and mechanical operating loads. As in all facets of the aerospace industry, engine designs are constantly driving towards increased performance, higher temperatures, higher speeds, and lower weight. The ability to address such requirements in a relatively short time frame has resulted in a major thrust towards integrated design/analysis/manufacturing systems. These computer driven graphics systems represent a unique challenge, with major payback opportunities if properly conceived, implemented, and applied.

Engineering analyses of large precision cathode strip chambers for GEM

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

Horvath, J.A.; Belser, F.C.; Pratuch, S.M.

Structural analyses of large precision cathode strip chambers performed up to the date of this publication are documented. Mechanical property data for typical chamber materials are included. This information, originally intended to be an appendix to the {open_quotes}CSC Structural Design Bible,{close_quotes} is presented as a guide for future designers of large chambers.

Role to Be Played by Independent Geotechnical Supervision in the Foundation for Bridge Construction

NASA Astrophysics Data System (ADS)

Sobala, Dariusz; Rybak, Jarosław

2017-10-01

Some remarks concerning the necessity of employing an independent and over all ethical geotechnical survey were presented in the paper. Starting from the design phase, through the whole construction process, the importance of geotechnical engineer is stated in legal acts. Numerous testing technologies serve for the calibration of geotechnical technologies and allow for confirming the quality and capacity of piles. Special emphasis was payed to the involvement of scientifical and research institutions which can not only serve services but also can postprocess and methodize collected data. Such databases enable for new codes, methods and recommendations. Selection of deep foundations for bridge-type structures is most often dependent on complex geotechnical conditions, concentrated loads and constraints for pier displacements. Besides the last ones, prior to more common introduction of the design-construct system, could be a convenient justification for design engineer, who imposed deep foundation because he did not want or was not able to estimate the effect of pier settlement on civil engineering structure. The paper provides some notes about the need to engage a geotechnical supervising service of high competency and ethical quality during engineering and construction stages of foundations for bridge-type structures where legal requirements are of special consideration. Successive stages of projects are reviewed and research methods used for current calibration of geotechnical technologies and verification of geotechnical work quality are analysed. Special attention is given to potential involvement of independent R&D institutions which, apart from rendering specific services, also collect and systemize the research results thus enabling, in the long term, to revise engineering standards, instructions and guidelines.

Multi-Disciplinary Design Optimization Using WAVE

NASA Technical Reports Server (NTRS)

Irwin, Keith

2000-01-01

The current preliminary design tools lack the product performance, quality and cost prediction fidelity required to design Six Sigma products. They are also frequently incompatible with the tools used in detailed design, leading to a great deal of rework and lost or discarded data in the transition from preliminary to detailed design. Thus, enhanced preliminary design tools are needed in order to produce adequate financial returns to the business. To achieve this goal, GEAE has focused on building the preliminary design system around the same geometric 3D solid model that will be used in detailed design. With this approach, the preliminary designer will no longer convert a flowpath sketch into an engine cross section but rather, automatically create 3D solid geometry for structural integrity, life, weight, cost, complexity, producibility, and maintainability assessments. Likewise, both the preliminary design and the detailed design can benefit from the use of the same preliminary part sizing routines. The design analysis tools will also be integrated with the 3D solid model to eliminate manual transfer of data between programs. GEAE has aggressively pursued the computerized control of engineering knowledge for many years. Through its study and validation of 3D CAD programs and processes, GEAE concluded that total system control was not feasible at that time. Prior CAD tools focused exclusively on detail part geometry and Knowledge Based Engineering systems concentrated on rules input and data output. A system was needed to bridge the gap between the two to capture the total system. With the introduction of WAVE Engineering from UGS, the possibilities of an engineering system control device began to formulate. GEAE decided to investigate the new WAVE functionality to accomplish this task. NASA joined GEAE in funding this validation project through Task Order No. 1. With the validation project complete, the second phase under Task Order No. 2 was established to develop an associative control structure (framework) in the UG WAVE environment enabling multi-disciplinary design of turbine propulsion systems. The capabilities of WAVE were evaluated to assess its use as a rapid optimization and productivity tool. This project also identified future WAVE product enhancements that will make the tool still more beneficial for product development.

Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

NASA Astrophysics Data System (ADS)

Berg, Thomas A.; Disney, Richard K.

2004-02-01

Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs.

Engineering and Fabrication Considerations for Cost-Effective Space Reactor Shield Development

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

Berg, Thomas A.; Disney, Richard K.

Investment in developing nuclear power for space missions cannot be made on the basis of a single mission. Current efforts in the design and fabrication of the reactor module, including the reactor shield, must be cost-effective and take into account scalability and fabricability for planned and future missions. Engineering considerations for the shield need to accommodate passive thermal management, varying radiation levels and effects, and structural/mechanical issues. Considering these challenges, design principles and cost drivers specific to the engineering and fabrication of the reactor shield are presented that contribute to lower recurring mission costs.

Research Reports: 1988 NASA/ASEE Summer Faculty Fellowship Program

NASA Technical Reports Server (NTRS)

Freeman, L. Michael (Editor); Chappell, Charles R. (Editor); Cothran, Ernestine K. (Editor); Karr, Gerald R. (Editor)

1988-01-01

The basic objectives are to further the professional knowledge of qualified engineering and science faculty members; to stimulate an exchange of ideas between participants and NASA: to enrich and refresh the research and teaching activities of the participants' institutions; and to contribute to the research objectives of the NASA centers. Topics addressed include: cryogenics; thunderstorm simulation; computer techniques; computer assisted instruction; system analysis weather forecasting; rocket engine design; crystal growth; control systems design; turbine pumps for the Space Shuttle Main engine; electron mobility; heat transfer predictions; rotor dynamics; mathematical models; computational fluid dynamics; and structural analysis.

NASA James Webb Space Telescope Engineering of the Primary Mirror Segment Assemblies (PMSA) and the Primary Mirror Backplane Support Structure (PMBSS)

NASA Technical Reports Server (NTRS)

Cohen, Lester M.

2015-01-01

The design, engineering tests of the PMSAs PMBSS show that we have a robust system that not only meets but exceeds (better than) the design requirements for these components. In the next 2 years the Telescope Observatory will be subjected to a simulated launch environment (sine vibeacoustics) and operations tests at cryogenic temperatures. Launch is schedule for the last quarter of 2018.

Selection of a turbine cooling system applying multi-disciplinary design considerations.

PubMed

Glezer, B

2001-05-01

The presented paper describes a multi-disciplinary cooling selection approach applied to major gas turbine engine hot section components, including turbine nozzles, blades, discs, combustors and support structures, which maintain blade tip clearances. The paper demonstrates benefits of close interaction between participating disciplines starting from early phases of the hot section development. The approach targets advancements in engine performance and cost by optimizing the design process, often requiring compromises within individual disciplines.

Formal Verification of Complex Systems based on SysML Functional Requirements

DTIC Science & Technology

2014-12-23

Formal Verification of Complex Systems based on SysML Functional Requirements Hoda Mehrpouyan1, Irem Y. Tumer2, Chris Hoyle2, Dimitra Giannakopoulou3...requirements for design of complex engineered systems. The proposed ap- proach combines a SysML modeling approach to document and structure safety requirements...methods and tools to support the integration of safety into the design solution. 2.1. SysML for Complex Engineered Systems Traditional methods and tools

Application of an integrated flight/propulsion control design methodology to a STOVL aircraft

NASA Technical Reports Server (NTRS)

Garg, Sanjay; Mattern, Duane L.

1991-01-01

Results are presented from the application of an emerging Integrated Flight/Propulsion Control (IFPC) design methodology to a Short Take Off and Vertical Landing (STOVL) aircraft in transition flight. The steps in the methodology consist of designing command shaping prefilters to provide the overall desired response to pilot command inputs. A previously designed centralized controller is first validated for the integrated airframe/engine plant used. This integrated plant is derived from a different model of the engine subsystem than the one used for the centralized controller design. The centralized controller is then partitioned in a decentralized, hierarchical structure comprising of airframe lateral and longitudinal subcontrollers and an engine subcontroller. Command shaping prefilters from the pilot control effector inputs are then designed and time histories of the closed loop IFPC system response to simulated pilot commands are compared to desired responses based on handling qualities requirements. Finally, the propulsion system safety and nonlinear limited protection logic is wrapped around the engine subcontroller and the response of the closed loop integrated system is evaluated for transients that encounter the propulsion surge margin limit.