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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.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Integrated flight/propulsion control design for a STOVL aircraft using H-infinity control design techniques

Results are presented from an application of H-infinity control design methodology to a centralized integrated flight propulsion control (IFPC) system design for a supersonic Short Takeoff and Vertical Landing (STOVL) fighter aircraft in transition flight. The emphasis is on formulating the H-infinity control design problem such that the resulting controller provides robustness to modeling uncertainties and model parameter variations with flight condition. Experience gained from a preliminary H-infinity based IFPC design study performed earlier is used as the basis to formulate the robust H-infinity control design problem and improve upon the previous design. Detailed evaluation results are presented for a reduced order controller obtained from the improved H-infinity control design showing that the control design meets the specified nominal performance objectives as well as provides stability robustness for variations in plant system dynamics with changes in aircraft trim speed within the transition flight envelope. A controller scheduling technique which accounts for changes in plant control effectiveness with variation in trim conditions is developed and off design model performance results are presented.

Garg, Sanjay↗
NASA NTRS1991

Integrated controls-structures design - A practical design tool for modern spacecraft

An integrated controls-structures design approach is developed for a class of flexible spacecraft. The integrated design problem is posed in the form of simultaneous optimization of both the structural and the control design variables. The approach is demonstrated by application to the integrated design of a geostationary platform and to a ground-based flexible structure experiment. The numerical results obtained indicate that the integrated design approach can yield spacecraft designs that have substantially superior performance over the conventional design approach wherein the structural design and control design are performed sequentially.

Maghami, P. G.↗
NASA NTRS1994

Analytical Design Package (ADP2): A computer aided engineering tool for aircraft transparency design

The Analytical Design Package (ADP2) is being developed as a part of the Air Force Frameless Transparency Program (FTP). ADP2 is an integrated design tool consisting of existing analysis codes and Computer Aided Engineering (CAE) software. The objective of the ADP2 is to develop and confirm an integrated design methodology for frameless transparencies, related aircraft interfaces, and their corresponding tooling. The application of this methodology will generate high confidence for achieving a qualified part prior to mold fabrication. ADP2 is a customized integration of analysis codes, CAE software, and material databases. The primary CAE integration tool for the ADP2 is P3/PATRAN, a commercial-off-the-shelf (COTS) software tool. The open architecture of P3/PATRAN allows customized installations with different applications modules for specific site requirements. Integration of material databases allows the engineer to select a material, and those material properties are automatically called into the relevant analysis code. The ADP2 materials database will be composed of four independent schemas: CAE Design, Processing, Testing, and Logistics Support. The design of ADP2 places major emphasis on the seamless integration of CAE and analysis modules with a single intuitive graphical interface. This tool is being designed to serve and be used by an entire project team, i.e., analysts, designers, materials experts, and managers. The final version of the software will be delivered to the Air Force in Jan. 1994. The Analytical Design Package (ADP2) will then be ready for transfer to industry. The package will be capable of a wide range of design and manufacturing applications.

Wuerer, J. E.↗
NASA NTRS1995

A synthetic design environment for ship design

Rapid advances in computer science and information system technology have made possible the creation of synthetic design environments (SDE) which use virtual prototypes to increase the efficiency and agility of the design process. This next generation of computer-based design tools will rely heavily on simulation and advanced visualization techniques to enable integrated product and process teams to concurrently conceptualize, design, and test a product and its fabrication processes. This paper summarizes a successful demonstration of the feasibility of using a simulation based design environment in the shipbuilding industry. As computer science and information science technologies have evolved, there have been many attempts to apply and integrate the new capabilities into systems for the improvement of the process of design. We see the benefits of those efforts in the abundance of highly reliable, technologically complex products and services in the modern marketplace. Furthermore, the computer-based technologies have been so cost effective that the improvements embodied in modern products have been accompanied by lowered costs. Today the state-of-the-art in computerized design has advanced so dramatically that the focus is no longer on merely improving design methodology; rather the goal is to revolutionize the entire process by which complex products are conceived, designed, fabricated, tested, deployed, operated, maintained, refurbished and eventually decommissioned. By concurrently addressing all life-cycle issues, the basic decision making process within an enterprise will be improved dramatically, leading to new levels of quality, innovation, efficiency, and customer responsiveness. By integrating functions and people with an enterprise, such systems will change the fundamental way American industries are organized, creating companies that are more competitive, creative, and productive.

Chipman, Richard R.↗
NASA NTRS1996

The Study of the Relationship between Probabilistic Design and Axiomatic Design Methodology

The structural design, or the design of machine elements, has been traditionally based on deterministic design methodology. The deterministic method considers all design parameters to be known with certainty. This methodology is, therefore, inadequate to design complex structures that are subjected to a variety of complex, severe loading conditions. A nonlinear behavior that is dependent on stress, stress rate, temperature, number of load cycles, and time is observed on all components subjected to complex conditions. These complex conditions introduce uncertainties; hence, the actual factor of safety margin remains unknown. In the deterministic methodology, the contingency of failure is discounted; hence, there is a use of a high factor of safety. It may be most useful in situations where the design structures are simple. The probabilistic method is concerned with the probability of non-failure performance of structures or machine elements. It is much more useful in situations where the design is characterized by complex geometry, possibility of catastrophic failure, sensitive loads and material properties. Also included: Comparative Study of the use of AGMA Geometry Factors and Probabilistic Design Methodology in the Design of Compact Spur Gear Set.

Onwubiko, Chin-Yere↗
NASA NTRS1998

Comparison of High Aspect Ratio Cooling Channel Designs for a Rocket Combustion Chamber with Development of an Optimized Design

An analytical investigation on the effect of high aspect ratio (height/width) cooling channels, considering different coolant channel designs, on hot-gas-side wall temperature and coolant pressure drop for a liquid hydrogen cooled rocket combustion chamber, was performed. Coolant channel design elements considered were: length of combustion chamber in which high aspect ratio cooling was applied, number of coolant channels, and coolant channel shape. Seven coolant channel designs were investigated using a coupling of the Rocket Thermal Evaluation code and the Two-Dimensional Kinetics code. Initially, each coolant channel design was developed, without consideration for fabrication, to reduce the hot-gas-side wall temperature from a given conventional cooling channel baseline. These designs produced hot-gas-side wall temperature reductions up to 22 percent, with coolant pressure drop increases as low as 7.5 percent from the baseline. Fabrication constraints for milled channels were applied to the seven designs. These produced hot-gas-side wall temperature reductions of up to 20 percent, with coolant pressure drop increases as low as 2 percent. Using high aspect ratio cooling channels for the entire length of the combustion chamber had no additional benefit on hot-gas-side wall temperature over using high aspect ratio cooling channels only in the throat region, but increased coolant pressure drop 33 percent. Independent of coolant channel shape, high aspect ratio cooling was able to reduce the hot-gas-side wall temperature by at least 8 percent, with as low as a 2 percent increase in coolant pressure drop. ne design with the highest overall benefit to hot-gas-side wall temperature and minimal coolant pressure drop increase was the design which used bifurcated cooling channels and high aspect ratio cooling in the throat region. An optimized bifurcated high aspect ratio cooling channel design was developed which reduced the hot-gas-side wall temperature by 18 percent and reduced the coolant pressure drop by 4 percent. Reductions of coolant mass flow rate of up to 50 percent were possible before the hot-gas-side wall temperature reached that of the baseline. These mass flow rate reductions produced coolant pressure drops of up to 57 percent.

Wadel, Mary F.↗
NASA NTRS2000

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

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.

Inman, Daniel J.↗
NASA NTRS2014

Innovation in Deep Space Habitat Interior Design: Lessons Learned From Small Space Design in Terrestrial Architecture

Increased public awareness of carbon footprints, crowding in urban areas, and rising housing costs have spawned a 'small house movement' in the housing industry. Members of this movement desire small, yet highly functional residences which are both affordable and sensitive to consumer comfort standards. In order to create comfortable, minimum-volume interiors, recent advances have been made in furniture design and approaches to interior layout that improve both space utilization and encourage multi-functional design for small homes, apartments, naval, and recreational vehicles. Design efforts in this evolving niche of terrestrial architecture can provide useful insights leading to innovation and efficiency in the design of space habitats for future human space exploration missions. This paper highlights many of the cross-cutting architectural solutions used in small space design which are applicable to the spacecraft interior design problem. Specific solutions discussed include reconfigurable, multi-purpose spaces; collapsible or transformable furniture; multi-purpose accommodations; efficient, space saving appliances; stowable and mobile workstations; and the miniaturization of electronics and computing hardware. For each of these design features, descriptions of how they save interior volume or mitigate other small space issues such as confinement stress or crowding are discussed. Finally, recommendations are provided to provide guidance for future designs and identify potential collaborations with the small spaces design community.

Simon, Matthew A.↗
NASA NTRS2016

Application of Design of Experiments and Surrogate Modeling within the NASA Advanced Concepts Office, Earth-to-Orbit Design Process

Decisions made during early conceptual design have a large impact upon the expected life-cycle cost (LCC) of a new program. It is widely accepted that up to 80% of such cost is committed during these early design phases [1]. Therefore, to help minimize LCC, decisions made during conceptual design must be based upon as much information as possible. To aid in the decision making for new launch vehicle programs, the Advanced Concepts Office (ACO) at NASA Marshall Space Flight Center (MSFC) provides rapid turnaround pre-phase A and phase A concept definition studies. The ACO team utilizes a proven set of tools to provide customers with a full vehicle mass breakdown to tertiary subsystems, preliminary structural sizing based upon worst-case flight loads, and trajectory optimization to quantify integrated vehicle performance for a given mission [2]. Although the team provides rapid turnaround for single vehicle concepts, the scope of the trade space can be limited due to analyst availability and the manpower requirements for manual execution of the analysis tools. In order to enable exploration of a broader design space, the ACO team has implemented an advanced design methods (ADM) based approach. This approach applies the concepts of design of experiments (DOE) and surrogate modeling to more exhaustively explore the trade space and provide the customer with additional design information to inform decision making. This paper will first discuss the automation of the ACO tool set, which represents a majority of the development effort. In order to fit a surrogate model within tolerable error bounds a number of DOE cases are needed. This number will scale with the number of variable parameters desired and the complexity of the system's response to those variables. For all but the smallest design spaces, the number of cases required cannot be produced within an acceptable timeframe using a manual process. Therefore, automation of the tools was a key enabler for the successful application of an ADM approach to an ACO design study. Following the overview of the tool set automation, an example problem will be given to illustrate the implementation of the ADM approach. The example problem will first cover the inclusion of ground rules and assumptions (GR&A) for a study. The GR&A are very important to the study as they determine the constraints within which a trade study can be conducted. These trades must ultimately reconcile with the customer's desired output and any anticipated "what if" questions.

Zwack, Mathew R.↗
NASA NTRS2015

Techniques for Conducting Effective Concept Design and Design-to-Cost Trade Studies

Concept design plays a central role in project success as its product effectively locks the majority of system life cycle cost. Such extraordinary leverage presents a business case for conducting concept design in a credible fashion, particularly for first-of-a-kind systems that advance the state of the art and that have high design uncertainty. A key challenge, however, is to know when credible design convergence has been achieved in such systems. Using a space system example, this paper characterizes the level of convergence needed for concept design in the context of technical and programmatic resource margins available in preliminary design and highlights the importance of design and cost evaluation learning curves in determining credible convergence. It also provides techniques for selecting trade study cases that promote objective concept evaluation, help reveal unknowns, and expedite convergence within the trade space and conveys general practices for conducting effective concept design-to-cost studies.

Design To Cost↗
NASA NTRS2015

Techniques for Conducting Effective Concept Design and Design-to-Cost Trade Studies

Concept design plays a central role in project success as its product effectively locks the majority of system life cycle cost. Such extraordinary leverage presents a business case for conducting concept design in a credible fashion, particularly for first-of-a-kind systems that advance the state of the art and that have high design uncertainty. A key challenge, however, is to know when credible design convergence has been achieved in such systems. Using a space system example, this paper characterizes the level of convergence needed for concept design in the context of technical and programmatic resource margins available in preliminary design and highlights the importance of design and cost evaluation learning curves in determining credible convergence. It also provides techniques for selecting trade study cases that promote objective concept evaluation, help reveal unknowns, and expedite convergence within the trade space and conveys general practices for conducting effective concept design-to-cost studies.

Trade Studies↗
NASA NTRSDate not supplied

Thermal Design for the New Era of Lunar Instruments: Lessons Learned from NASA Goddard Space Flight Center’s Instrument Design Laboratory

As NASA enters the Age of Artemis, the resurgence of interest in the Moon has not only contributed to rapid development of crewed vehicles and habitats, it has also inspired a design renaissance for robotic and astronaut-deployed instrumentation for the lunar surface. NASA Goddard Space Flight Center’s Instrument Design Laboratory (IDL) has been at the forefront of lunar instrument concept design, and in recent years has used its collaborative and concurrent process to design instruments ranging from small devices held or worn by astronauts to large lander- or rover-mounted instruments with multiple scientific or technical functions. This paper explores the wide spectrum of lunar instruments studied by the IDL within the past few years and their thermal design nuances. A series of lessons learned will be used to categorize the general trends prevalent across lunar-specific design and the thermal and systems-level drivers for instrumentation on the surface of the Moon. While the instruments investigated in this work are not named due to their competition sensitivity and proprietary nature, it is hoped that the lessons learned captured here will help identify specific design drivers and areas of focus for the thermal and systems engineers designing the next generation of lunar instrumentation.

Lunar, instrument, artemis, design, IDL, Goddard↗
NASA NTRS1982

Design guidelines for the testability of microprocessor based logic designs

This paper deals with the issue of designing microprocessor based systems with testability in mind. The ease of eventual testability should be a design consideration from the earliest design stage. Design guidelines with explicit examples for ease of testability are given. The issue of testing microprocessors as contrasted with testing random logic design is addressed, and procedures are delineated for the testability of microprocessors. Microprocessor testability design guidelines are discussed both at the design stage of the microprocessor itself as well as at the stage where the processor is imbedded as a component in a larger system. Specific instances and examples of a collection of design do's and don'ts are provided.

Mathur, F. P.↗
NASA NTRS1988

Advanced piloted aircraft flight control system design methodology. Volume 2: The FCX flight control design expert system

The development of a comprehensive and electric methodology for conceptual and preliminary design of flight control systems is presented and illustrated. The methodology is focused on the design states starting with the layout of system requirements and ending when some viable competing system architectures (feedback control structures) are defined. The approach is centered on the human pilot and the aircraft as both the sources of, and the keys to the solution of, many flight control problems. The methodology relies heavily on computational procedures which are highly interactive with the design engineer. To maximize effectiveness, these techniques, as selected and modified to be used together in the methodology, form a cadre of computational tools specifically tailored for integrated flight control system preliminary design purposes. The FCX expert system as presently developed is only a limited prototype capable of supporting basic lateral-directional FCS design activities related to the design example used. FCX presently supports design of only one FCS architecture (yaw damper plus roll damper) and the rules are largely focused on Class IV (highly maneuverable) aircraft. Despite this limited scope, the major elements which appear necessary for application of knowledge-based software concepts to flight control design were assembled and thus FCX represents a prototype which can be tested, critiqued and evolved in an ongoing process of development.

Myers, Thomas T.↗
NASA NTRS1991

Integrated flight/propulsion control design for a STOVL aircraft using H-infinity control design techniques

Results are presented from an application of H(infinity) control design methodology to a centralized integrated flight/propulsion control (IFPC) system design for a supersonic short take-off and vertical landing (STOVL) fighter aircraft in transition flight. The emphasis is on formulating the H(infinity) control design problem such that the resulting controller provides robustness to modeling uncertainties and model parameter variations with flight condition. Experience gained from a preliminary H(infinity)=based IFPC design study performed earlier is used as the base to formulate the robust H(infinity) control design problem and improve the previous design. Detailed evaluation results are presented for a reduced-order controller obtained from the improved H(infinity) control design showing that the control design meets the specified nominal performance objectives as well as provides stability robustness for variations in plant system dynamics with chnages in aircraft trim speed within the transition flight envelope.

Garg, Sanjay↗
NASA NTRS1992

The suitability of selected multidisciplinary design and optimization techniques to conceptual aerospace vehicle design

Four methods for preliminary aerospace vehicle design are reviewed. The first three methods (classical optimization, system decomposition, and system sensitivity analysis (SSA)) employ numerical optimization techniques and numerical gradients to feed back changes in the design variables. The optimum solution is determined by stepping through a series of designs toward a final solution. Of these three, SSA is argued to be the most applicable to a large-scale highly coupled vehicle design where an accurate minimum of an objective function is required. With SSA, several tasks can be performed in parallel. The techniques of classical optimization and decomposition can be included in SSA, resulting in a very powerful design method. The Taguchi method is more of a 'smart' parametric design method that analyzes variable trends and interactions over designer specified ranges with a minimum of experimental analysis runs. Its advantages are its relative ease of use, ability to handle discrete variables, and ability to characterize the entire design space with a minimum of analysis runs.

Olds, John R.↗
NASA NTRS1993

NASA advanced design program. Design and analysis of a radio-controlled flying wing aircraft

The main challenge of this project was to design an aircraft that will achieve stability while flying without a horizontal tail. The project focused on both the design, analysis and construction of a remotely piloted, elliptical shaped flying wing. The design team was composed of four sub-groups each of which dealt with the different aspects of the design, namely aerodynamics, stability and control, propulsion, and structures. Each member of the team initially researched the background information pertaining to specific facets of the project. Since previous work on this topic was limited, most of the focus of the project was directed towards developing an understanding of the natural instability of the aircraft. Once the design team entered the conceptual stage of the project, a series of compromises had to be made to satisfy the unique requirements of each sub-group. As a result of the numerous calculations and iterations necessary, computers were utilized extensively. In order to visualize the design and layout of the wing, engines and control surfaces, a solid modeling package was used to evaluate optimum design placements. When the design was finalized, construction began with the help of all the members of the project team. The nature of the carbon composite construction process demanded long hours of manual labor. The assembly of the engine systems also required precision hand work. The final product of this project is the Elang, a one-of-a-kind remotely piloted aircraft of composite construction powered by two ducted fan engines.

Source record↗
NASA NTRS1997

Electronic Design Automation: Integrating the Design and Manufacturing Functions

As the complexity of electronic systems grows, the traditional design practice, a sequential process, is replaced by concurrent design methodologies. A major advantage of concurrent design is that the feedback from software and manufacturing engineers can be easily incorporated into the design. The implementation of concurrent engineering methodologies is greatly facilitated by employing the latest Electronic Design Automation (EDA) tools. These tools offer integrated simulation of the electrical, mechanical, and manufacturing functions and support virtual prototyping, rapid prototyping, and hardware-software co-design. This report presents recommendations for enhancing the electronic design and manufacturing capabilities and procedures at JSC based on a concurrent design methodology that employs EDA tools.

Bachnak, Rafic↗