Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “design methodology”

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.

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

At least 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Suggested criteria for evaluating systems engineering methodologies

Systems engineering is the application of mathematical and scientific principles to practical ends in the life-cycle of a system. A methodology for systems engineering is a carefully developed, relatively complex procedure or process for applying these mathematical and scientific principles. There are many systems engineering methodologies (or possibly many versions of a few methodologies) currently in use in government and industry. These methodologies are usually designed to meet the needs of a particular organization. It has been observed, however, that many technical and non-technical problems arise when inadequate systems engineering methodologies are applied by organizations to their systems development projects. Various criteria for evaluating systems engineering methodologies are discussed. Such criteria are developed to assist methodology-users in identifying and selecting methodologies that best fit the needs of the organization.

Gates, Audrey↗
NASA NTRS1987

Methods for evaluating integrated airframe/propulsion control system architectures

Methodology, analysis, and detailed design of integrated control system architectures suitable for high-performance aircraft of the 1990s are presented. A methodology, with supporting analytical tools, has been developed to provide system designers with the capability to specify candidate architectures and accurately predict their reliability and performance in the early stages of design development. The authors address the methodology and supporting tools.

Gerald C Cohen↗
NASA NTRS1986

Simulation studies for the NASA scatterometer on NROSS

A methodology for the design of a spaceborne radar scatterometer system configuration which includes parameters such as antenna pointing angles, antenna azimuth angles, antenna polarization, and measurement swath locations is presented. The methodology was applied to the NASA Scatterometer (NSCAT). The performance tradeoff studies on the NSCAT system configuration required development of a computer simulation to estimate wind retrieval accuracy for a given system configuration; and a series of metrics to quantify the simulation results and allow direct comparison of the performance for different configurations.

Chi, Chong-Yung↗
NASA NTRS1988

An approach to the parametric design of ion thrusters

A methodology that can be used to determine which of several physical constraints can limit ion thruster power and thrust, under various design and operating conditions, is presented. The methodology is exercised to demonstrate typical limitations imposed by grid system span-to-gap ratio, intragrid electric field, discharge chamber power per unit beam area, screen grid lifetime, and accelerator grid lifetime constraints. Limitations on power and thrust for a thruster defined by typical discharge chamber and grid system parameters when it is operated at maximum thrust-to-power are discussed. It is pointed out that other operational objectives such as optimization of payload fraction or mission duration can be substituted for the thrust-to-power objective and that the methodology can be used as a tool for mission analysis.

Wilbur, Paul J.↗
NASA NTRS1988

An approach to the parametric design of ion thrusters

A methodology that can be used to determine which of several physical constraints can limit ion thruster power and thrust, under various design and operating conditions, is presented. The methodology is exercised to demonstrate typical limitations imposed by grid system span-to-gap ratio, intragrid electric field, discharge chamber power per unit beam area, screen grid lifetime and accelerator grid lifetime constraints. Limitations on power and thrust for a thruster defined by typical discharge chamber and grid system parameters when it is operated at maximum thrust-to-power are discussed.

Wilbur, Paul J.↗
NASA NTRS1992

Structural design optimization with survivability dependent constraints application: Primary wing box of a multi-role fighter

The superior survivability of a multirole fighter is dependent upon balanced integration of technologies for reduced vulnerability and susceptability. The objective is to develop a methodology for structural design optimization with survivability dependent constraints. The design criteria for optimization will be survivability in a tactical laser environment. The following analyses are studied to establish a dependent design relationship between structural weight and survivability: (1) develop a physically linked global design model of survivability variables; and (2) apply conventional constraints to quantify survivability dependent design. It was not possible to develop an exact approach which would include all aspects of survivability dependent design, therefore guidelines are offered for solving similar problems.

Dolvin, Douglas J.↗
NASA NTRS1990

Optimization of aircraft configurations in a multidisciplinary environment

A decomposition and multidisciplinary optimization methodology for aircraft design is presented, based on multilevel optimization and use of global sensitivity equations to account for interdisciplinary effects. A brief study of a hypersonic cruise vehicle is developed to illustrate methodology. The vehicle is sized for minimum take-off gross weight considering aerodynamics, structures, and mission performance.

Logan, Trent R.↗
NASA NTRS1993

Methodology for sensitivity analysis, approximate analysis, and design optimization in CFD for multidisciplinary applications

In this study involving advanced fluid flow codes, an incremental iterative formulation (also known as the delta or correction form) together with the well-known spatially-split approximate factorization algorithm, is presented for solving the very large sparse systems of linear equations which are associated with aerodynamic sensitivity analysis. For smaller 2D problems, a direct method can be applied to solve these linear equations in either the standard or the incremental form, in which case the two are equivalent. Iterative methods are needed for larger 2D and future 3D applications, however, because direct methods require much more computer memory than is currently available. Iterative methods for solving these equations in the standard form are generally unsatisfactory due to an ill-conditioning of the coefficient matrix; this problem can be overcome when these equations are cast in the incremental form. These and other benefits are discussed. The methodology is successfully implemented and tested in 2D using an upwind, cell-centered, finite volume formulation applied to the thin-layer Navier-Stokes equations. Results are presented for two sample airfoil problems: (1) subsonic low Reynolds number laminar flow; and (2) transonic high Reynolds number turbulent flow.

Taylor, Arthur C., III↗
NASA NTRS2020

Reliability Analysis of Complex NASA Systems with Model-Based Engineering

The emergence of model-based engineering, with Model- Based Systems Engineering (MBSE) leading the way, is transforming design and analysis methodologies. The recognized benefits to systems development include moving from document-centric information systems and document-centric project communication to a model-centric environment in which control of design changes in the life cycles is facilitated. In addition, a “single source of truth” about the system, that is up-to-date in all respects of the design, becomes the authoritative source of data and information about the system. This promotes consistency and efficiency in regard to integration of the system elements as the design emerges and thereby may further optimize the design. Therefore Reliability Engineers (REs) supporting NASA missions must be integrated into model-based engineering to ensure the outputs of their analyses are relevant and value-needed to the design, development, and operational processes for failure risks assessment and communication.

FMEA/FMECA↗
NASA NTRS2020

Reliability Analysis of Complex NASA Systems with Model Based Engineering

The emergence of model-based engineering, with Model- Based Systems Engineering (MBSE) leading the way, is transforming design and analysis methodologies. The recognized benefits to systems development include moving from document-centric information systems and document-centric project communication to a model-centric environment in which control of design changes in the life cycles is facilitated. In addition, a “single source of truth” about the system, that is up-to-date in all respects of the design, becomes the authoritative source of data and information about the system. This promotes consistency and efficiency in regard to integration of the system elements as the design emerges and thereby may further optimize the design. Therefore Reliability Engineers (REs) supporting NASA missions must be integrated into model-based engineering to ensure the outputs of their analyses are relevant and value-needed to the design, development, and operational processes for failure risks assessment and communication.

Reliability prediction↗
NASA NTRSDate not supplied

System Safety Analysis of Complex NASA Systems with Model-Based Engineering (REV B)

The emergence of model-based engineering is transforming design and analysis methodologies. A recognized benefit of model-based engineering is the existence of a “single source of truth” about the system that becomes the authoritative source of data and information for designers, analysts, and developers. This promotes consistency and efficiency as the design emerges and can be used to further optimize the design. Integrating System Safety Engineers to the “single source of truth” will ensure that the outputs of their assessments and analyses are relevant to the design as it evolves. Use of an integrated system model enables near immediate evaluation of a design change as well as development of operational processes for risk assessment and communication. Such models can enable efficient and timely analysis of system hazards (e.g., hazard fault tree analysis and procedure simulations) and produce complete, accurate, and more consistent products (e.g., hazard reports and safety requirement evaluations). Therefore, an agency-sponsored team at Goddard Space Flight Center (GSFC) recently completed a System Safety Study of modeling and testing capabilities as part of a Model-Based Safety and Mission Assurance Initiative (MBSMAI). Using an existing model developed for reliability analyses, GSFC modeling and system safety experts performed system safety analysis/modeling and produced safety products. The team evaluated model-based feasibility to support System Safety Engineering, developed safety analysis modeling processes, and identified tool capability advancement/development needs. These study results indicate model-based engineering is valid and useable for System Safety Engineering for NASA if adequate modeling processes and environment are established.

NASA↗
NASA NTRS2021

Model-Based SMA Initiative Phase 1 Report: Reliability Tips Excerpt

The emergence of model-based engineering, with Model- Based Systems Engineering (MBSE) leading the way, is transforming design and analysis methodologies. [7] The recognized benefits to systems development include moving from document-centric information systems and document-centric project communication to a model-centric environment in which control of design changes in the life cycles is facilitated. In addition, a “single source of truth” about the system, that is up-to-date in all respects of the design, becomes the authoritative source of data and information about the system. This promotes consistency and efficiency in regard to integration of the system elements as the design emerges and thereby may further optimize the designs. Therefore Reliability Engineers (REs) supporting NASA missions must be integrated into model-based engineering, using these recommended modeling techniques, to ensure the outputs of their analyses are relevant and value-needed to the design, development, and operational processes for failure risk assessment and communication.

Nancy J. Lindsey↗
NASA NTRSDate not supplied

System Safety Analysis of Complex NASA Systems with Model-Based Engineering

The emergence of model-based engineering is transforming design and analysis methodologies [5]. A recognized benefit of model-based engineering is the existence of a “single source of truth” about the system that becomes the authoritative source of data and information for designers, analysts, and developers. This promotes consistency and efficiency as the design emerges and can be used to further optimize the design. Integrating System Safety Engineers to the “single source of truth” will ensure that the outputs of their assessments and analyses are relevant to the design as it evolves. Use of an integrated system model enables near immediate evaluation of a design change as well as development of operational processes for risk assessment and communication. Such models can enable efficient and timely analysis of system hazards (e.g., hazard fault tree analysis and procedure simulations) and produce complete, accurate, and more consistent products (e.g., hazard reports and safety requirement evaluations). Therefore, an agency-sponsored team at Goddard Space Flight Center (GSFC) recently completed a System Safety Study of modeling and testing capabilities as part of a Model-Based Safety and Mission Assurance Initiative (MBSMAI). Using an existing model developed for reliability analyses [1], GSFC modeling and system safety experts performed system safety analysis/modeling and produced safety products. The team evaluated model-based feasibility to support System Safety Engineering, developed safety analysis modeling processes, and identified tool capability advancement/development needs. These study results indicate model-based engineering is valid and useable for System

NASA↗
NASA NTRSDate not supplied

System Safety Analysis of Complex NASA Systems with Model Based Engineering

The emergence of model-based engineering is transforming design and analysis methodologies [5]. A recognized benefit of model-based engineering is the existence of a “single source of truth” about the system that becomes the authoritative source of data and information for designers, analysts, and developers. This promotes consistency and efficiency as the design emerges and can be used to further optimize the design. Integrating System Safety Engineers to the “single source of truth” will ensure that the outputs of their assessments and analyses are relevant to the design as it evolves. Use of an integrated system model enables near immediate evaluation of a design change as well as development of operational processes for risk assessment and communication. Such models can enable efficient and timely analysis of system hazards (e.g., hazard fault tree analysis and procedure simulations) and produce complete, accurate, and more consistent products (e.g., hazard reports and safety requirement evaluations). Therefore, an agency-sponsored team at Goddard Space Flight Center (GSFC) recently completed a System Safety Study of modeling and testing capabilities as part of a Model-Based Safety and Mission Assurance Initiative (MBSMAI). Using an existing model developed for reliability analyses [1], GSFC modeling and system safety experts performed system safety analysis/modeling and produced safety products. The team evaluated model-based feasibility to support System Safety Engineering, developed safety analysis modeling processes, and identified tool capability advancement/development needs. These study results indicate model-based engineering is valid and useable for System

Model Based Engineering↗
NASA NTRS2017

Designing for Annual Spacelift Performance

This paper presents a methodology for approaching space launch system design from a total architectural point of view. This different approach to conceptual design is contrasted with traditional approaches that focus on a single set of metrics for flight system performance, i.e., payload lift per flight, vehicle mass, specific impulse, etc. The approach presented works with a larger set of metrics, including annual system lift, or "spacelift" performance. Spacelift performance is more inclusive of the flight production capability of the total architecture, i.e., the flight and ground systems working together as a whole to produce flights on a repeated basis. In the proposed methodology, spacelift performance becomes an important design-for-support parameter for flight system concepts and truly advanced spaceport architectures of the future. The paper covers examples of existing system spacelift performance as benchmarks, points out specific attributes of space transportation systems that must be greatly improved over these existing designs, and outlines current activity in this area.

spaceports↗
NASA NTRSDate not supplied

Thermal Management System Design for Electrified Aircraft Propulsion Concepts

This paper describes the development of thermal management systems (TMS) for three electrified aircraft propulsion (EAP) vehicle concepts released by NASA that span the UAM, regional, and single-aisle markets. For each EAP concept, a conventional TMS is designed for two electric component technology levels: state of the art and advanced. The goals for the paper are to compare the TMS designs for the above EAP concepts, to study how changes in requirements affect the TMS subcomponents, and to develop generalized TMS sizing relations. Each conventional TMS concept utilizes a liquid-based cooling methodology and is designed to cool the EAP electrical components only. The design parameters considered in this study include TMS architecture variation due to differing vehicle cooling requirements, electrical component efficiencies, vehicle total fuel burn or energy consumption, and electrical component operating temperatures. Results show that cooling components with low temperature limits increases TMS weight and demonstrate that efficiency gains of the specific technologies can net a lower weight TMS system despite more stringent temperature limits.

Thermal Management System↗
NASA NTRSDate not supplied

Thermal Management System Design for Electrified Aircraft Propulsion Concepts

This paper describes the development of thermal management systems (TMS) for three electrified aircraft propulsion (EAP) vehicle concepts released by NASA that span the UAM, regional, and single-aisle markets. For each EAP concept, a conventional TMS is designed for two electric component technology levels: state of the art and advanced. The goals for the paper are to compare the TMS designs for the above EAP concepts, to study how changes in requirements affect the TMS subcomponents, and to develop generalized TMS sizing relations. Each conventional TMS concept utilizes a liquid-based cooling methodology and is designed to cool the EAP electrical components only. The design parameters considered in this study include TMS architecture variation due to differing vehicle cooling requirements, electrical component efficiencies, vehicle total fuel burn or energy consumption, and electrical component operating temperatures. Results show that cooling components with low temperature limits increases TMS weight and demonstrate that efficiency gains of the specific technologies can net a lower weight TMS system despite more stringent temperature limits.

Thermal management system↗
NASA NTRS2021

Thermal Management System Design for Electrified Aircraft Propulsion Concepts

This paper describes the development of thermal management systems (TMS) for three electrified aircraft propulsion (EAP) vehicle concepts released by NASA that span the UAM, regional, and single-aisle markets. For each EAP concept, a conventional TMS is designed for two electric component technology levels: state of the art and advanced. The goals for the paper are to compare the TMS designs for the above EAP concepts, to study how changes in requirements affect the TMS subcomponents, and to develop generalized TMS sizing relations. Each conventional TMS concept utilizes a liquid-based cooling methodology and is designed to cool the EAP electrical components only. The design parameters considered in this study include TMS architecture variation due to differing vehicle cooling requirements, electrical component efficiencies, vehicle total fuel burn or energy consumption, and electrical component operating temperatures. Results show that cooling components with low temperature limits increases TMS weight and demonstrate that efficiency gains of the specific technologies can net a lower weight TMS system despite more stringent temperature limits.

Thermal management system↗