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At least 451 records · Page 25

The Design Manager's Aid for Intelligent Decomposition (DeMAID)

Before the design of new complex systems such as large space platforms can begin, the possible interactions among subsystems and their parts must be determined. Once this is completed, the proposed system can be decomposed to identify its hierarchical structure. The design manager's aid for intelligent decomposition (DeMAID) is a knowledge based system for ordering the sequence of modules and identifying a possible multilevel structure for design. Although DeMAID requires an investment of time to generate and refine the list of modules for input, it could save considerable money and time in the total design process, particularly in new design problems where the ordering of the modules has not been defined.

Rogers, James L.↗

Predictive Models for Semiconductor Device Design and Processing

The device feature size continues to be on a downward trend with a simultaneous upward trend in wafer size to 300 mm. Predictive models are needed more than ever before for this reason. At NASA Ames, a Device and Process Modeling effort has been initiated recently with a view to address these issues. Our activities cover sub-micron device physics, process and equipment modeling, computational chemistry and material science. This talk would outline these efforts and emphasize the interaction among various components. The device physics component is largely based on integrating quantum effects into device simulators. We have two parallel efforts, one based on a quantum mechanics approach and the second, a semiclassical hydrodynamics approach with quantum correction terms. Under the first approach, three different quantum simulators are being developed and compared: a nonequlibrium Green's function (NEGF) approach, Wigner function approach, and a density matrix approach. In this talk, results using various codes will be presented. Our process modeling work focuses primarily on epitaxy and etching using first-principles models coupling reactor level and wafer level features. For the latter, we are using a novel approach based on Level Set theory. Sample results from this effort will also be presented.

Meyyappan, Meyya↗

Solder Joint Health Monitoring Testbed System

The density and pin count for Field Programmable Gate Arrays (FPGAs) has been increasing, and has exceeded current methods of solder joint inspection, making early detection of failures more problematic. These failures are a concern for both flight safety and maintenance in commercial aviation. Ridgetop Group, Inc. has developed a method for detecting solder joint failures in real time. The NASA Dryden Flight Research Center is developing a set of boards to test this method in ground environmental and accelerated testing as well as flight test on a Dryden F-15 or F-18 research aircraft. In addition to detecting intermittent and total solder joint failures, environmental data on the boards, such as temperature and vibration, will be collected and time-correlated to aircraft state data. This paper details the technical approach involved in the detection process, and describes the design process and products to date for Dryden s FPGA failure detection boards.

Delaney, Michael M.↗

The Role of Guidance, Navigation, and Control in Hypersonic Vehicle Multidisciplinary Design and Optimization

Airbreathing hypersonic systems offer distinct performance advantages over rocket-based systems for space access vehicles. However, these performance advantages are dependent upon advances in current state-of-the-art technologies in many areas such as ram/scramjet propulsion integration, high temperature materials, aero-elastic structures, thermal protection systems, transition to hypersonics and hypersonic control elements within the framework of complex physics and new design methods. The complex interactions between elements of an airbreathing hypersonic vehicle represent a new paradigm in vehicle design to achieve the optimal performance necessary to meet space access mission objectives. In the past, guidance, navigation, and control (GNC) analysis often follows completion of the vehicle conceptual design process. Individual component groups design subsystems which are then integrated into a vehicle configuration. GNC is presented the task of developing control approaches to meet vehicle performance objectives given that configuration. This approach may be sufficient for vehicles where significant performance margins exist. However, for higher performance vehicles engaging the GNC discipline too late in the design cycle has been costly. For example, the X-29 experimental flight vehicle was built as a technology demonstrator. One of the many technologies to be demonstrated was the use of light-weight material composites for structural components. The use of light-weight materials increased the flexibility of the X- 29 beyond that of conventional metal alloy constructed aircraft. This effect was not considered when the vehicle control system was designed and built. The impact of this is that the control system did not have enough control authority to compensate for the effects of the first fundamental structural mode of the vehicle. As a result, the resulting pitch rate response of the vehicle was below specification and no post-design changes could recover the desired capability.

Ouzts, Peter J.↗

NASA Marshall Space Flight Center Tools for Human Factors Engineering Assessments for Safe Sls Worksites

NASA Marshall Space Flight Center (MSFC) Human Factors Engineering (HFE) Team is implementing mockup fabrication, virtual reality (VR) and motion capture (MoCap) into HFE analyses of SLS worksites through its Virtual Environments Lab (VEL). MSFC HFE Team is responsible for the Space Launch System (SLS) worksite analyses of the integration activities performed at the Kennedy Space Center (KSC). With a wide variety of tasks, it is important to verify that SLS can be safely integrated at KSC early in the design process. If the ground support crew cannot safely complete the tasks, redesign efforts must be implemented. MSFC HFE is responsible for verification through methods such as drawing inspection, observation of tasks performed, and building physical mockups. There is a need, however, for a faster analysis early in the process that can impact design safety before drawings are finalized. This need is addressed through MSFC’s VEL.

Andrews, Tanya↗

Recurring Causes of Human Spaceflight Mishaps during Flight Tests and Early Operations

n analysis of recurring causes underlying human spaceflight mishaps that occurred during flight tests and early operations was performed. Eight mishaps from the Apollo, Soyuz, Skylab, Space Shuttle, and Constellation Programs (i.e., the Ares-1X test flight) and commercial suborbital systems were included in the study. Detailed event analyses were performed for the historical mishaps and aggregate data analyses conducted to identify recurring issues. The nine most frequent issues were inadequate technical controls or risk management practices, incomplete procedures, system design and development issues, inadequate inspection or secondary verification requirements, failures of organizations to learn from previous incidents, inadequate schedule controls, inadequate task analyses or design processes, flaws in the design of organizations, and issues with organizational safety cultures.

Timothy S Barth↗

Recurring Causes of Human Spaceflight Mishaps During Flight Tests and Early Operations

An analysis of recurring causes underlying human spaceflight mishaps that occurred during flight tests and early operations was performed. Eight mishaps from the Apollo, Soyuz, Skylab, Space Shuttle, and Constellation Programs (i.e., the Ares-1X test flight) and early commercial suborbital operations were included in the study. Detailed event analyses were performed for the historical mishaps and aggregate data analyses conducted to identify recurring issues. The nine most frequent issues were inadequate technical controls or risk management practices, incomplete procedures, system design and development issues, inadequate inspection or secondary verification requirements, failures of organizations to learn from previous incidents, inadequate schedule controls, inadequate task analyses or design processes, flaws in the design of organizations, and issues with organizational safety cultures.

Human Spaceflight↗

Multidisciplinary Optimization of an Electric Quadrotor Urban Air Mobility Aircraft

Urban Air Mobility (UAM) vehicles have the potential to augment urban transportation systems, allowing passengers to skip the traffic below for a fee. This emerging market is opening up the design space for a new class of Urban Air Mobility (UAM) vehicles which could be powered by electric propulsion systems to be economical and environmentally friendly. However, development of these UAM concepts presents several additional challenges in the design process. First, these concept designs require including new disciplinary models for subsystems including the electric motors, cables, batteries and thermal management systems. Second, correctly designing and evaluating these various subsystems requires tight coupling between the discipline models to capture interactions. This paper presents the continued development of a multidisciplinary design optimization environment to aid in the development of these vehicle concepts. The multidisciplinary environment fully couples the various subsystem models allowing for the full vehicle to be designed and optimized simultaneously. In this research, the developed modeling approach is demonstrated in the analysis of a small, all-electric quadrotor UAM concept. Results from these studies show that numerous disciplines can be tightly coupled and producing improved overall vehicle designs.

Multidisciplinary Optimization↗

Mars 2020 Trajectory Correction Maneuver Design

The Mars 2020 mission launched on 30 July 2020 and arrived at Mars on 18 February 2021. Delivering the mission’s Perseverance rover to Jezero Crater required adjusting the postlaunch trajectory to remove the launch injection bias and to target the atmospheric entry conditions, while also satisfying requirements on the propellant usage and non-nominal impact probability at Mars. The Mars 2020 maneuver design team achieved these goals by designing and executing three propulsive maneuvers in flight. The accurate on-board execution of those maneuvers delivered the spacecraft into the Martian atmosphere in a state that allowed for a successful entry, descent, and landing on the surface. This paper details the maneuver design process and describes the design and execution of the three in-flight propulsive maneuvers.

Kruizinga, Gerhard↗

Design and Analysis of a 25 MWe Supercritical CO2 Turbo Machine

This paper presents the design and analysis of a turbo machine operating with supercritical carbon dioxide (sCO2) in a 25 MWe Recompression Brayton Cycle (RCBC). The work was performed under US Department of Energy (DoE) program DE-EE-0010318. The design process involves the aerodynamic design of the compressor and turbine, including the initial layout of flowpaths and stage configurations to achieve high efficiency and performance. Additionally, a comprehensive rotodynamic analysis is performed to ensure the stability and reliability of the system. Conceptual designs for a high-speed motor and synchronous generator that match turbomachinery requirements are also developed from first principles.

42 ENGINEERING↗

Modeling and analysis of power processing systems: Feasibility investigation and formulation of a methodology

A review is given of future power processing systems planned for the next 20 years, and the state-of-the-art of power processing design modeling and analysis techniques used to optimize power processing systems. A methodology of modeling and analysis of power processing equipment and systems has been formulated to fulfill future tradeoff studies and optimization requirements. Computer techniques were applied to simulate power processor performance and to optimize the design of power processing equipment. A program plan to systematically develop and apply the tools for power processing systems modeling and analysis is presented so that meaningful results can be obtained each year to aid the power processing system engineer and power processing equipment circuit designers in their conceptual and detail design and analysis tasks.

Biess, J. J.↗

A software development and evolution model based on decision-making

Design is a complex activity whose purpose is to construct an artifact which satisfies a set of constraints and requirements. However the design process is not well understood. The software design and evolution process is the focus of interest, and a three dimensional software development space organized around a decision-making paradigm is presented. An initial instantiation of this model called 3DPM(sub p) which was partly implemented, is presented. Discussion of the use of this model in software reuse and process management is given.

Wild, J. Christian↗

Process Feasibility Study in Support of Silicon Material, Task 1

During this reporting period, major activies were devoted to process system properties, chemical engineering and economic analyses. Analyses of process system properties was continued for materials involved in the alternate processes under consideration for solar cell grade silicon. The following property data are reported for silicon tetrafluoride: critical constants, vapor pressure, heat of varporization, heat capacity, density, surface tension, viscosity, thermal conductivity, heat of formation and Gibb's free energy of formation. Chemical engineering analysis of the BCL process was continued with primary efforts being devoted to the preliminary process design. Status and progress are reported for base case conditions; process flow diagram; reaction chemistry; material and energy balances; and major process equipment design.

Li, K. Y.↗

Capturing, Analyzing, Maintaining, and Disseminating Shape Memory Material Data Between Information Management Systems

With an increased demand on reducing the time, cost, and effort to develop new materials, Integrated Computational Materials Engineering (ICME) has received widespread attention in various engineering disciplines as a catalyst for significantly reducing experimental testing during the material design process. An ICME approach to design can enable ‘fit-for-purpose’ materials to be realized in engineering applications by incorporating well-understood process-property-performance relationships between the various length and time scales in a material’s structure, enabling material optimization. However, such an approach requires validated multiscale models at the various length scales for a material, which in turn requires a large amount of data, a robust means of storing the data, and the ability to link data to developed material models. The NASA Vision 2040 [1] has identified nine key elements to enabling ICME approaches in system level design, with one being “Data, Information, and Visualization”, thus outlining the importance of a robust information management system for ICME. As the relationship between microstructure, properties, and material performance become better understood and incorporated into multiscale models that can be leveraged in application design, the emergence of new materials with application-driven properties can be realized. One such new material class that has seen growing attention are shape memory materials (SMM), in which a material can transition between a deformed and undeformed state via a reversible phase transformation when subject to a thermal, mechanical, or magnetic load [2]. SMMs have been used widely in aerospace and biomedical industries, including applications such as actuators, low-shock mechanisms, medical staples, braces, and stents [3, 4]. These materials exhibit unique behavior due to their ability to transition between phases, and thus the mechanisms that enable this transition must be captured in a data information management system and incorporated into SMM material models. At NASA Glenn Research Center, the Shape Memory Materials Database (SMMD) Tool has been developed to capture the necessary information that governs SMM material behavior and provide users the ability to select and visualize various SMMs for a specific application [5]. The database contains point-wise data for published SMM materials, along with the pedigree metadata for traceability necessary for a robust information management system. The database is also capable of storing in-house test data performed at NASA GRC by interacting with the developed Shape Memory Alloy (SMA) Analytics tool to extract the necessary point-wise values and populate the database. Although the SMMD Tool offers its users a single, authoritative source for SMM material data that is critical for model development and material design, the full material pedigree of the in-house test data for SMMs is not currently captured and is out of the scope for the SMMD tool. In this work, the schema for capturing SMM test data within the larger NASA GRC ICME Schema [6, 7, 8, 9] will be developed and implemented for thermomechanical tests conducted at NASA GRC. The developed schema will not only store the relevant data needed for the SMMD tool, but also the material pedigree (i.e., production of the bulk material, bulk material analysis, sample cut-out diagrams, sample fabrication procedure, etc.), test pedigree (i.e., test equipment used, measurement systems used, raw test data), and analysis pedigree (i.e., how the data in the SMMD tool is calculated). Furthermore, a Python-based framework will be developed to seamlessly interact between the SMA Analytics and SMMD tools, which will write the full dataset and associated metadata to the GRC Information Management System before passing the required point-wise data to the SMMD tool. Data informatics is a key element of the NASA Vision 2040, which requires not only that data is stored and maintained throughout the material lifecycle, but that the data is also accessible and reusable such that material development efforts can be minimized. Therefore, for an ICME design approach to be realized, a centralized information management system that drives the ICME process must be able to communicate with other databases. The work that will be presented in this presentation will therefore not only demonstrate the ability of NASA GRC’s information management system to capture SMM data, but also its ability to interact with pre-existing tools specialized for such materials.

Data management↗

The Ganymede Interior Structure, and Magnetosphere Observer (GISMO) Mission Concept

The NASA Planetary Science Summer School (PSSS) at JPL offers graduate students and young professionals a unique opportunity to learn about the mission design process. Program participants select and design a mission based on a recent NASA Science Mission Directorate Announcement of Opportunity (AO). Starting with the AO, in this case the 2009 New Frontiers AO, participants generate a set of science goals and develop a early mission concept to accomplish those goals within the constraints provided. As part of the 2010 NASA PSSS, the Ganymede Interior, Surface, and Magnetosphere Observer (GISMO) team developed a preliminary satellite design for a science mission to Jupiter's moon Ganymede. The science goals for this design focused on studying the icy moon's magnetosphere, internal structure, surface composition, geological processes, and atmosphere. By the completion of the summer school an instrument payload was selected and the necessary mission requirements were developed to deliver a spacecraft to Ganymede that would accomplish the defined science goals. This poster will discuss those science goals, the proposed spacecraft and the proposed mission design of this New Frontiers class Ganymede observer.

radar sounder↗

Does human cognition allow Human Factors (HF) certification of advanced aircrew systems?

This paper has examined the requirements of HF specification and certification within advanced or complex aircrew systems. It suggests reasons for current inadequacies in the use of HF in the design process, giving some examples in support, and suggesting an avenue towards the improvement of the HF certification process. The importance of human cognition to the operation and performance of advanced aircrew systems has been stressed. Many of the shortfalls of advanced aircrew systems must be attributed to over automated designs that show little consideration on either the mental limits or the cognitive capabilities of the human system component. Traditional approaches to system design and HF certification are set within an over physicalistic foundation. Also, traditionally it was assumed that physicalistic system functions could be attributed to either the human or the machine on a one to one basis. Moreover, any problems associated with the parallel needs, or promoting human understanding alongside system operation and direction, were generally equated in reality by the natural flexibility and adaptability of human skills. The consideration of the human component of a complex system is seen as being primarily based on manifestations of human behavior to the almost total exclusion of any appreciation of unobservable human mental and cognitive processes. The argument of this paper is that the considered functionality of any complex human-machine system must contain functions that are purely human and purely cognitive. Human-machine system reliability ultimately depends on human reliability and dependability and, therefore, on the form and frequency of cognitive processes that have to be conducted to support system performance. The greater the demand placed by an advanced aircraft system on the human component's basic knowledge processes or cognition, rather than on skill, the more insiduous the effects the human may have on that system. This paper discusses one example of an attempt to devise an improved method of specificaiton and certification with relation to the advanced aircrew system, that of the RN Merlin helicopter. The method is realized to have limitations in practice, these mainly associated with the late production of the system specification in relation to the system development process. The need for a careful appreciation of the capabilities and support needs of human cognition within the design process of a complex man machine system has been argued, especially with relation to the concept of system functionality. Unlike the physicalistic Fitts list, a new classification of system functionality is proposed, namely: (1) equipment - system equipment related; (2) cognitive - human cognition related; and (3) associated - necessary combinatin of equipment and cognitive. This paper has not proposed a method for a fuller consideration of cognition within systems design, but has suggested the need for such a method and indicated an avenue towards its development. Finally, the HF certification of advanced aircrew systems is seen as only being possible in a qualified sense until the important functions of human cognition are considered within the system design process. (This paper contains the opinions of its authors and does not necessarily refledt the standpoint of their respective organizations).

Macleod, Iain S.↗

Planar Inlet Design and Analysis Process (PINDAP)

The Planar Inlet Design and Analysis Process (PINDAP) is a collection of software tools that allow the efficient aerodynamic design and analysis of planar (two-dimensional and axisymmetric) inlets. The aerodynamic analysis is performed using the Wind-US computational fluid dynamics (CFD) program. A major element in PINDAP is a Fortran 90 code named PINDAP that can establish the parametric design of the inlet and efficiently model the geometry and generate the grid for CFD analysis with design changes to those parameters. The use of PINDAP is demonstrated for subsonic, supersonic, and hypersonic inlets.

Slater, John W.↗