SEARCH · Engineering Papers

Results for “design process”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49

All sources NASA NTRS DOE OSTI

NASA NTRS1983

Structural control research and experiments at NASA/LaRC

The advances made in the area of structural dynamics and control using the flexible beam facility at the NASA Langley Research Center are surveyed. Spectral attention is given to the progress in adaptive control and reliability improvements using advanced control concepts. Both theoretical and experimental results are given to delineate the nature of the work being undertaken. With regard to adaptive control, emphasis is placed on parameter and system identification and on comparisons between competing on-line algorithms. In addition, results are presented for on-line modal control laws that are interfaced to a parameter identification scheme. This gives an on-line distributed adaptive control system. With regard to reliability, a design process is outlined that incorporates reliability over the design mission life.

Montgomery, R. C.↗

NASA NTRS1985

A modal parameter extraction procedure applicable to linear time-invariant dynamic systems

Modal analysis has emerged as a valuable tool in many phases of the engineering design process. Complex vibration and acoustic problems in new designs can often be remedied through use of the method. Moreover, the technique has been used to enhance the conceptual understanding of structures by serving to verify analytical models. A new modal parameter estimation procedure is presented. The technique is applicable to linear, time-invariant systems and accommodates multiple input excitations. In order to provide a background for the derivation of the method, some modal parameter extraction procedures currently in use are described. Key features implemented in the new technique are elaborated upon.

Kurdila, A. J.↗

NASA NTRS1983

Structural control research and experiments at NASA/LaRC

Research progress in the area of structural dynamics and control using the flexible beam facility at the NASA Langley Research Center is reviewed. Particular attention is placed on the progress in adaptive control and reliability improvements using advanced control concepts. Both theoretical and experimental results are given to indicate the nature of the work being undertaken. In the adaptive control area, emphasis is placed on parameter and system identification and in comparison of competing on-line algorithms. Also, results are presented for on-line modal control laws that are interfaced to a parameter identification scheme. This provides an on-line distributed adaptive control system. In the reliability area, a design process is outlined that incorporates reliability over the design mission life.

Montgomery, R. C.↗

NASA NTRS1986

Interdisciplinary and multilevel optimum design

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.

Sobieszczanski-Sobieski, Jaroslaw↗

NASA NTRS1987

Interdisciplinary and multilevel optimum design

Sobieszczanski-Sobieski, Jaroslaw↗

NASA NTRS1989

The potential application of the blackboard model of problem solving to multidisciplinary design

Problems associated with the sequential approach to multidisciplinary design are discussed. A blackboard model is suggested as a potential tool for implementing the multilevel decomposition approach to overcome these problems. The blackboard model serves as a global database for the solution with each discipline acting as a knowledge source for updating the solution. With this approach, it is possible for engineers to improve the coordination, communication, and cooperation in the conceptual design process, allowing them to achieve a more optimal design from an interdisciplinary standpoint.

Rogers, J. L.↗

NASA NTRS1990

EDNA: Expert fault digraph analysis using CLIPS

Traditionally fault models are represented by trees. Recently, digraph models have been proposed (Sack). Digraph models closely imitate the real system dependencies and hence are easy to develop, validate and maintain. However, they can also contain directed cycles and analysis algorithms are hard to find. Available algorithms tend to be complicated and slow. On the other hand, the tree analysis (VGRH, Tayl) is well understood and rooted in vast research effort and analytical techniques. The tree analysis algorithms are sophisticated and orders of magnitude faster. Transformation of a digraph (cyclic) into trees (CLP, LP) is a viable approach to blend the advantages of the representations. Neither the digraphs nor the trees provide the ability to handle heuristic knowledge. An expert system, to capture the engineering knowledge, is essential. We propose an approach here, namely, expert network analysis. We combine the digraph representation and tree algorithms. The models are augmented by probabilistic and heuristic knowledge. CLIPS, an expert system shell from NASA-JSC will be used to develop a tool. The technique provides the ability to handle probabilities and heuristic knowledge. Mixed analysis, some nodes with probabilities, is possible. The tool provides graphics interface for input, query, and update. With the combined approach it is expected to be a valuable tool in the design process as well in the capture of final design knowledge.

Dixit, Vishweshwar V.↗

NASA NTRS1996

Development of an agility assessment module for preliminary fighter design

A FORTRAN computer program is presented to perform agility analysis on fighter aircraft configurations. This code is one of the modules of the NASA Ames ACSYNT (AirCraft SYNThesis) design code. The background of the agility research in the aircraft industry and a survey of a few agility metrics are discussed. The methodology, techniques, and models developed for the code are presented. FORTRAN programs were developed for two specific metrics, CCT (Combat Cycle Time) and PM (Pointing Margin), as part of the agility module. The validity of the code was evaluated by comparing with existing flight test data. Example trade studies using the agility module along with ACSYNT were conducted using Northrop F-20 Tigershark and McDonnell Douglas F/A-18 Hornet aircraft models. The sensitivity of thrust loading and wing loading on agility criteria were investigated. The module can compare the agility potential between different configurations and has the capability to optimize agility performance in the preliminary design process. This research provides a new and useful design tool for analyzing fighter performance during air combat engagements.

Ngan, Angelen↗

NASA NTRS1996

Utilization of an agility assessment module in analysis and optimization of preliminary fighter configuration

A study has been conducted to develop and to analyze a FORTRAN computer code for performing agility analysis on fighter aircraft configurations. This program is one of the modules of the NASA Ames ACSYNT (AirCraft SYNThesis) design code. The background of the agility research in the aircraft industry and a survey of a few agility metrics are discussed. The methodology, techniques, and models developed for the code are presented. The validity of the existing code was evaluated by comparing with existing flight test data. A FORTRAN program was developed for a specific metric, PM (Pointing Margin), as part of the agility module. Example trade studies using the agility module along with ACSYNT were conducted using a McDonnell Douglas F/A-18 Hornet aircraft model. Tile sensitivity of thrust loading, wing loading, and thrust vectoring on agility criteria were investigated. The module can compare the agility potential between different configurations and has capability to optimize agility performance in the preliminary design process. This research provides a new and useful design tool for analyzing fighter performance during air combat engagements in the preliminary design.

Ngan, Angelen↗

NASA NTRS2003

Case Study of "Engineering Peer Meetings" in JPL's ST-6 Project

This design process error-proofing case study describes a design review practice implemented by a project manager at NASA Jet Propulsion Laboratory. There are many types of reviews at NASA: required and not, formalized and informal, programmatic and technical. Standing project formal reviews such as the Preliminary Design Review (PDR) and Critical Design Review (CDR) are a required part of every project and mission development. However, the engineering peer reviews that support teams technical work on such projects are often informal, ad hoc, and inconsistent across the organization. This case study discusses issues and innovations identified by a project manager at JPL and implemented in "engineering peer meetings" for his group.

Tumer, Irem Y.↗

NASA NTRS2004

Case Study of 'Engineering Peer Meetings' in JPL's ST-6 Project

Chao, Lawrence P.↗

NASA NTRS2006

Advanced Space Suit Portable Life Support Subsystem Packaging Design

This paper discusses the Portable Life Support Subsystem (PLSS) packaging design work done by the NASA and Hamilton Sundstrand in support of the 3 future space missions; Lunar, Mars and zero-g. The goal is to seek ways to reduce the weight of PLSS packaging, and at the same time, develop a packaging scheme that would make PLSS technology changes less costly than the current packaging methods. This study builds on the results of NASA s in-house 1998 study, which resulted in the "Flex PLSS" concept. For this study the present EMU schematic (low earth orbit) was used so that the work team could concentrate on the packaging. The Flex PLSS packaging is required to: protect, connect, and hold the PLSS and its components together internally and externally while providing access to PLSS components internally for maintenance and for technology change without extensive redesign impact. The goal of this study was two fold: 1. Bring the advanced space suit integrated Flex PLSS concept from its current state of development to a preliminary design level and build a proof of concept mockup of the proposed design, and; 2. "Design" a Design Process, which accommodates both the initial Flex PLSS design and the package modifications, required to accommodate new technology.

Howe, Robert↗

NASA NTRS2003

Update on Integrated Optical Design Analyzer

Updated information on the Integrated Optical Design Analyzer (IODA) computer program has become available. IODA was described in Software for Multidisciplinary Concurrent Optical Design (MFS-31452), NASA Tech Briefs, Vol. 25, No. 10 (October 2001), page 8a. To recapitulate: IODA facilitates multidisciplinary concurrent engineering of highly precise optical instruments. The architecture of IODA was developed by reviewing design processes and software in an effort to automate design procedures. IODA significantly reduces design iteration cycle time and eliminates many potential sources of error. IODA integrates the modeling efforts of a team of experts in different disciplines (e.g., optics, structural analysis, and heat transfer) working at different locations and provides seamless fusion of data among thermal, structural, and optical models used to design an instrument. IODA is compatible with data files generated by the NASTRAN structural-analysis program and the Code V (Registered Trademark) optical-analysis program, and can be used to couple analyses performed by these two programs. IODA supports multiple-load-case analysis for quickly accomplishing trade studies. IODA can also model the transient response of an instrument under the influence of dynamic loads and disturbances.

Moore, James D., Jr.↗

NASA NTRS2014

EVA Suit R and D for Performance Optimization

Designing a planetary suit is very complex and often requires difficult trade‐offs between performance, cost, mass, and system complexity. To verify that new suit designs meet requirements, full prototypes must be built and tested with human subjects. However, numerous design iterations will occur before the hardware meets those requirements. Traditional draw‐prototype‐test paradigms for R&D are prohibitively expensive with today's shrinking Government budgets. Personnel at NASA are developing modern simulation techniques which focus on human‐centric designs by creating virtual prototype simulations and fully adjustable physical prototypes of suit hardware. During the R&D design phase, these easily modifiable representations of an EVA suit's hard components will allow designers to think creatively and exhaust design possibilities before they build and test working prototypes with human subjects. It allows scientists to comprehensively benchmark current suit capabilities and limitations for existing suit sizes and sizes that do not exist. This is extremely advantageous and enables comprehensive design down‐selections to be made early in the design process, enables the use of human performance as design criteria, and enables designs to target specific populations

Cowley, Matthew S.↗

NASA NTRS2014

Aeroelastic Optimization Study Based on the X-56A Model

One way to increase the aircraft fuel efficiency is to reduce structural weight while maintaining adequate structural airworthiness, both statically and aeroelastically. A design process which incorporates the object-oriented multidisciplinary design, analysis, and optimization (MDAO) tool and the aeroelastic effects of high fidelity finite element models to characterize the design space was successfully developed and established. This paper presents two multidisciplinary design optimization studies using an object-oriented MDAO tool developed at NASA Armstrong Flight Research Center. The first study demonstrates the use of aeroelastic tailoring concepts to minimize the structural weight while meeting the design requirements including strength, buckling, and flutter. Such an approach exploits the anisotropic capabilities of the fiber composite materials chosen for this analytical exercise with ply stacking sequence. A hybrid and discretization optimization approach improves accuracy and computational efficiency of a global optimization algorithm. The second study presents a flutter mass balancing optimization study for the fabricated flexible wing of the X-56A model since a desired flutter speed band is required for the active flutter suppression demonstration during flight testing. The results of the second study provide guidance to modify the wing design and move the design flutter speeds back into the flight envelope so that the original objective of X-56A flight test can be accomplished successfully. The second case also demonstrates that the object-oriented MDAO tool can handle multiple analytical configurations in a single optimization run.

flutter constraints↗

NASA NTRS2014

Aeroelastic Optimization Study Based on X-56A Model

A design process which incorporates the object-oriented multidisciplinary design, analysis, and optimization (MDAO) tool and the aeroelastic effects of high fidelity finite element models to characterize the design space was successfully developed and established. Two multidisciplinary design optimization studies using an object-oriented MDAO tool developed at NASA Armstrong Flight Research Center were presented. The first study demonstrates the use of aeroelastic tailoring concepts to minimize the structural weight while meeting the design requirements including strength, buckling, and flutter. A hybrid and discretization optimization approach was implemented to improve accuracy and computational efficiency of a global optimization algorithm. The second study presents a flutter mass balancing optimization study. The results provide guidance to modify the fabricated flexible wing design and move the design flutter speeds back into the flight envelope so that the original objective of X-56A flight test can be accomplished.

flutter constraints↗

DOE OSTI2013

Proliferation resistance assessments during the design phase of a recycling facility as a means of reducing proliferation risks

The sustainability criterion for Gen IV nuclear energy systems inherently presumes the availability of efficient fuel recycling capabilities. One area for research on advanced fuel recycling concerns safeguards aspects of this type of facilities. Since a recycling facility may be considered as sensitive from a non-proliferation perspective, it is important to address these issues early in the design process, according to the principle of Safeguards By Design. Presented in this paper is a mode of procedure, where assessments of the proliferation resistance (PR) of a recycling facility for fast reactor fuel have been performed so as to identify the weakest barriers to proliferation of nuclear material. Two supplementing established methodologies have been applied; TOPS (Technological Opportunities to increase Proliferation resistance of nuclear power Systems) and PR-PP (Proliferation Resistance and Physical Protection evaluation methodology). The chosen fuel recycling facility belongs to a small Gen IV lead-cooled fast reactor system that is under study in Sweden. A schematic design of the recycling facility, where actinides are separated using solvent extraction, has been examined. The PR assessment methodologies make it possible to pinpoint areas in which the facility can be improved in order to reduce the risk of diversion. The initial facility design may then be slightly modified and/or safeguards measures may be introduced to reduce the total identified proliferation risk. After each modification of design and/or safeguards implementation, a new PR assessment of the revised system can then be carried out. This way, each modification can be evaluated and new ways to further enhance the proliferation resistance can be identified. This type of iterative procedure may support Safeguards By Design in the planning of new recycling plants and other nuclear facilities. (authors)

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2017

Early implementation of digital upgrades on simulators - 347

An important aspect of successful Nuclear Power Plant (NPP) digital control system upgrade projects is to upgrade the Operator Training Simulator (OTS) or a related Engineering Simulator (ES), prior to installation of the Distributed Control System (DCS) on the plant allowing for early testing of the digital controls/HMI and for early training of the plant operators while maintaining OTS configuration management (i.e. OTS in sync with the plant's current design). Experience has shown that early implementation of digital upgrades on the OTS and/or an ES can reduce plant startup duration (related to digital systems commissioning) and ensure operators are proficient with the new digital systems to ensure safe and reliable plant operation. Including simulators in the design process offers many benefits including early identification of design deficiencies, testing deficiency fixes, developing and validating plant procedures and supporting human factors engineering, to name a few. Implementing digital upgrades on the OTS is also a regulatory requirement driven by the ANSI/ANS-3.5-2009 standard (Nuclear Power Plant Simulators for Use in Operator Training and Examination) if the new DCS affects actions to be taken by the plant operator in the main control room. This paper presents the benefits of implementing digital upgrades on the OTS and/or ES prior to plant implementation. The various simulator implementation strategies (stimulation, emulation, simulation or a hybrid solution) and selection factors are discussed. The paper also covers four (4) case studies demonstrating how digital upgrades can be implemented on simulators. The first case study covers the implementation of a Siemens offgas Programmable Logic Controller (PLC) system on the Enrico Fermi OTS (Michigan). The second case study covers the implementation of a GE main generator excitation system on the Cernavoda OTS (Romania). The third case study covers the implementation of a Siemens main feedwater control system on the Callaway OTS and ES (Missouri). The final case study covers the implementation of the non-safety related and safety related DCS on the Nuclear New Build (NNB) Hongyanhe Phase I dual-purpose OTS/ES (China). (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗