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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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At least 37 records · Page 2

Simulation development and evaluation of an improved longitudinal velocity vector control wheel steering mode and electronic display format

Using simulation, an improved longitudinal velocity vector control wheel steering mode and an improved electronic display format for an advanced flight system were developed and tested. Guidelines for the development phase were provided by test pilot critique summaries of the previous system. The results include performances from computer generated step column inputs across the full airplane speed and configuration envelope, as well as piloted performance results taken from a reference line tracking task and an approach to landing task conducted under various environmental conditions. The analysis of the results for the reference line tracking and approach to landing tasks indicates clearly detectable improvement in pilot tracking accuracy with a reduction in physical workload. The original objectives of upgrading the longitudinal axis of the velocity vector control wheel steering mode were successfully met when measured against the test pilot critique summaries and the original purpose outlined for this type of augment control mode.

Steinmetz, G. G.↗

Flexural Fatigue Testing and Qualification of Hybrid PAN-pitch Composite Materials with High Through-Thickness Thermal Conductivity

Carbon-fiber-reinforced polymers (CFRPs) considered for motor components within future electric vertical takeoff and landing (eVTOL) vehicles require not only a high strength-to-weight ratio but also a high through-thickness thermal conductivity (TC) to dissipate heat. Previously, CFRPs incorporating pitch CF interleaves demonstrated an increased through-thickness TC relative to the baseline composite, but the effect on flexural fatigue life was not evaluated. For this work, T700S/TC275–1 braided carbon fiber/epoxy prepreg baseline (no interleave), YSH–60A pitch interleave, and YS–80A pitch interleave configurations were tested for fatigue life. A combination of ASTM International Standards D7264 and D3479 were used to develop a reliable testing method. An Instron® (Illinois Tool Works Inc.) 8501 servohydraulic system with a fatigue test fixture was set up with a 16:1 span:thickness ratio, load ratio R set to 0.1, and frequency of 4 Hz. High-cycle fatigue testing was completed, and it was found that YSH–60A interleave performed slightly better than YS–80A below 100,000 cycles but showed no differences above 100,000 cycles. In all cases, the baseline CFRP had superior fatigue life performance both in terms of stress handled and total cycles to failure. These fatigue testing data will inform future use of hybrid CFRP materials by highlighting the tradeoff between increased through-thickness TC and fatigue life. Testing guidelines, equipment, and parameters for static and fatigue tests were successfully outlined for CFRPs.

composites↗

Biaxial thermo-mechanical fatigue

Stress-strain and durability information is often desirable for situations in which strain and temperature are changing simultaneously. To obtain such information, strain controlled uniaxial push-pull tests have typically been done. In order to control the mechanical strain, it is necessary in such tests to compute the mechanical strain from the total measured strain using measured temperature and the thermal expansion properties of the specimen. A system for conducting torsional thermomechanical tests is described which has the great advantage that the torsional strain is unaffected by the changing temperature and thus real time computations of quantities is not required for control of the test and the mechanical strain need not be determined from the subtraction of two measured qnantities as is the case in the uniaxial test. In addition to describing torsional thermomechanical tests, guidelines for software to be used in running biaxial thermomechanical tests will also be presented.

Jordan, Eric H.↗

Comparative evaluation of test methods to simulate acoustic response of shroud-enclosed spacecraft structures

Test methods were evaluated to ascertain whether a spacecraft, properly tested within its shroud, could be vibroacoustic tested without the shroud, with adjustments made in the acoustic input spectra to simulate the acoustic response of the missing shroud. The evaluation was based on vibroacoustic test results obtained from a baseline model composed (1) of a spacecraft with adapter, lower support structure, and shroud; (2) of the spacecraft, adapter, and lower structure, but without the shroud; and (3) of the spacecraft and adapter only. Emphasis was placed on the magnitude of the acoustic input changes required to substitute for the shroud and the difficulty of making such input changes, and the degree of missimulation which can result from the performance of a particular, less-than optimum test. Conclusions are drawn on the advantages and disadvantages derived from the use of input spectra adjustment methods and lower support structure simulations. Test guidelines were also developed for planning and performing a launch acoustic-environmental test.

On, F. J.↗

Designing the Next Generation of Human Spacecraft

Lunar Space Station Common Module: A new concept for a module for a lunar space station attempts to reduce the module's mass by abandoning the traditional rack structure currently used on the ISS for the mounting of internal hardware and replacing it with a core structure. By using this design, the pressure shell will not have to carry the loads resulting from the internal mass. I worked with another intern to create the initial design for the module, with him focusing on the core and myself focusing on the pressure shell. To start, I was given the shell overall dimensions and material and tasked with sizing the wall thickness and placing stiffeners such that the shell could withstand the required loads. At the same time, I had to keep the mass to a minimum to keep the overall module within the allowable launch mass. Once I had done initial sizing based on pressure loads, I combined the pressure shell with the inner core to perform optimization of the design. Currently, the design involves circumferential stiffeners along the entire length of the pressure shell with longitudinal stiffeners on either end. In addition, extra wall thickness was added around each of the hatches. At this stage, the design shows a comparable mass to a more traditional design, but we are hopeful that, through optimization, we will be able to reduce the mass even further. There is currently a patent pending for the module design, for which I am listed as a co-inventor. ALON Material Testing: I was given samples of aluminum oxynitride (ALON) that had been impacted by a previous intern on which to perform residual strength tests as part of a plan to approve them for space use. Before testing, I measured the pucks and their damages using a ruler and optical micrometer in order to verify that the puck dimensions were within the tolerances set by the test guidelines and that the damages had not grown when the pucks were thinned. The test was a ring-ring test, which used two concentric rings to place the ring in axisymmetric bending, with the puck set up so that the damaged side was always in tension. Though I was unable to do the setup of the test or run the load machine due to a period of changing test procedures, I was able to observe the testing and perform the data collection. The pucks behaved as expected, breaking at the damage, as did the strengths calculated from the data, being lower than for the unimpacted pucks and having less scatter between the puck values. The attached image is of myself during the ALON strength testing. Over the course of my internship, I was able to learn much more about real-life structural analysis and about the behavior of materials, and it confirmed my previous interest in structural analysis. At the same time, due to the opportunities offered to interns, I was able to learn a lot about mission control, and, in doing so, I developed a second interest in working in mission control. In addition, being able to meet the people here and learn about the type of work NASA does made me want to come back to work for NASA full time.

Simmons, Emily↗

NEPP Update of Independent Single Event Upset Field Programmable Gate Array Testing

This presentation provides a NASA Electronic Parts and Packaging (NEPP) Program update of independent Single Event Upset (SEU) Field Programmable Gate Array (FPGA) testing including FPGA test guidelines, Microsemi RTG4 heavy-ion results, Xilinx Kintex-UltraScale heavy-ion results, Xilinx UltraScale+ single event effect (SEE) test plans, development of a new methodology for characterizing SEU system response, and NEPP involvement with FPGA security and trust.

Field Programmable Gate Array (FPGA); Triple Modul↗

Ampaire ARPA-e Electric Flight Testbed

A hybrid-electric aircraft flying testbed was developed in this program with the intent to serve as a dedicated, enduring testbed to test and evaluate ARPA-e CIRCUITS Program and other electrified aviation technologies in relevant flight environments. This testbed enabled rapid development cycles of novel and innovative technologies in the electrified aviation space, maturing them from a research lab environment to flying in an aircraft. By providing research groups with the means to test their transformative technologies in a real-world, aircraft environment, the path to validating the safety and reliability of their technologies for future commercial opportunities was greatly accelerated. Three core technologies were integrated and tested: an inverter/motor drive built by the University of Arkansas, a solid-state circuit breaker (iBreaker) built by the Illinois Institute of Technology, and a Flying Capacitor Multi-level (FCML) DC/DC converter built by the University of California, Berkeley. In each of these cases, the requirements established for safety of flight resulted in a holistic approach to the designs, evoking a deeper understanding of the potential failure modes and mitigations necessary to build a robust and flightworthy system. Further, the integration into a hybrid-electric aircraft de-risked the potential electrical and mechanical issues that cannot easily be experienced or replicated in a lab environment. The experiments were also required to undergo representative temperature, shock, and vibration testing as the FAA prescribes for this category of aircraft, facilitating familiarity with the relevant design and test guidelines necessary to commercialize the technologies. This testbed unlocks the massive potential of core power electronics technologies necessary for a safe, robust, and efficient electric aviation future. With quick iterative design, test, and flight cycles, these core technologies are on a quicker path to technology readiness level maturity and commercialization, enabling a more sustainable future for the aviation industry.

24 POWER TRANSMISSION AND DISTRIBUTION↗

A guideline for heavy ion radiation testing for Single Event Upset (SEU)

A guideline for heavy ion radiation testing for single event upset was prepared to assist new experimenters in preparing and directing tests. How to estimate parts vulnerability and select an irradiation facility is described. A broad brush description of JPL equipment is given, certain necessary pre-test procedures are outlined and the roles and testing guidelines for on-site test personnel are indicated. Detailed descriptions of equipment needed to interface with JPL test crew and equipment are not provided, nor does it meet the more generalized and broader requirements of a MIL-STD document. A detailed equipment description is available upon request, and a MIL-STD document is in the early stages of preparation.

Nichols, D. K.↗

ORNL Contributions to the ENDF/B-VIII.1 Library [Slides]

For uranium and plutonium isotopes, evaluation work is converging to a stable configuration with an overall satisfactory benchmark performance (more information on the validation tests after CSEWG). Strontium evaluation was included in the repository library and successfully tested by processing codes relative to an alternative quantification of the external function. Cerium covariance matrices were updated to address review comments on the magnitude of the uncertainty. For future uncertainty quantification, theoretical observables should be properly decoupled from current measured guidelines. Tests to correctly include LP (from resonance parameters) fitted to measured energy-averaged data are in progress. Current ENDF files contains experimental LP data.

07 ISOTOPE AND RADIATION SOURCES↗

Vacuum stability requirements of polymeric material for spacecraft application

The purpose of this document is to establish outgassing requirements and test guidelines for polymeric materials used in the space thermal/vacuum environment around sensitive optical or thermal control surfaces. The scope of this document covers the control of polymeric materials used near or adjacent to optical or thermal control surfaces that are exposed to the thermal/vacuum environment of space. This document establishes the requirements and defines the test method to evaluate polymeric materials used in the vicinity of these surfaces in space applications.

Craig, J. W.↗

An Overview of the NASA Lift+Cruise eVTOL Crash Test

Introduction – NASA RVLT Project Impact Dynamics / Crash Safety Task - Task Objective: “To improve the crashworthiness and impact safety of Urban Air Mobility (UAM) vehicle and provide data to simplify the certification process. Efforts will include development of validated computational models of these vehicles, as well as other impacting bodies such as birds and drones. Efforts will also focus on developing and evaluating energy absorbing and crush properties of emerging and non-traditional composite materials and processes. Finally, occupant protection will be addressed using computational models and physical assets as it pertains to all rotorcraft environments.” - Problem Statement: “There currently is a lack of data for requirements regarding the crashworthy performance of UAM vehicles and impact loads generated by a bird strike. To address this technology gap, NASA will develop test guidelines, adopt modeling methodologies demonstrating capability for ‘certification by analysis’, acquire vehicle and occupant data on full-scale representative vehicles, and provide data/guidance to consensus standards organizations and the UAM community.” - 4 Main focus points - The investigation of occupant injury using physical and computational assets - The development of energy absorbing technology - The generation of data from sub- and full-scale crash test data - The execution of advanced finite element modelling techniques

evtol↗

IROS 2023 Workshop Report: Draft Guidelines on Manufacturing Procedures, Test Methods and Reporting for Soft Robotics

Soft roboticists are facing challenges with reproducibility, which prevents researchers from making holistic comparisons to prior work, impedes full understanding of results, and forces the need to “reinvent the wheel,” delaying fundamental advances. Reproducibility of results is key to advancing science as well as achieving technology transfer from research laboratories to industrial applications. Recently, a discussion-based workshop dedicated to the topic, “Developing Standard Testing and Reporting Guidelines for Soft Robotics,” was held at IROS 2023 in Detroit, MI. The purpose of this document is to record a set of recommendations and voluntary draft guidelines for soft roboticists concerning fabrication/manufacturing, test procedures, and reporting, which were collectively developed at the workshop. Together as a community, we hope to improve the reporting standards of soft robotics and drive the field as a whole toward more rigorous research practices.

43 PARTICLE ACCELERATORS↗

A Biochar Classification System and Associated Test Methods

In this chapter, a biochar classification system related to its use as soil amendment is proposed. This document builds upon previous work: “Standardized product definition and product testing guidelines for biochar that is used in soil” (IBI, 2015) (aka IBI Biochar Standards) and “Guidelines for biochar production for a sustainable production of biochar: European Biochar Certificate” (EBC, 2012-2022) (aka EBC Biochar Standards). It should be noted that the EBC guidelines constitute the basis for biochar certification through the independent government accredited inspection agency, Bio.Inspecta AG. The present document constrains its scope to materials with properties that satisfy the criteria for biochar as defined by either the IBI Biochar Standards or the EBC Standards (Annex I), as required by the current methodologies developed for accounting carbon credits associated with the biochar use in the voluntary market (e.g., Verra, Puro.Earth). The classification system envisions enabling stakeholders and commercial entities to (i) identify the most suitable biochar to fulfil the requirements for a particular soil and/or land-use, (ii) distinguish the application of biochar for specific niches (e.g., soilless agriculture), and (iii) assess the climate-impact value based on biochar properties, production efficiency, and alternative feedstock uses. It is based on the best current knowledge and will need to be improved as new data and knowledge become available in the scientific literature.

biochar, climate change impacts, soil amendment, c↗

Production development of organic nonflammable spacecraft potting, encapsulating and conformal coating compounds. Volume 3: Appendices

Appendices are presented which include: statement of work; material vendor contacts; formulation/processing data sheet; upward propagation test; flammability test conditions/results sheet; odor test; vacuum stability requirements; flammability test facility; determination of offgassing products and carbon monoxide test; and pneumatic and mechanical impact test guidelines.

Lieberman, S. L.↗

American Airlines LOFT evaluation program

The development of a test program to evaluate recurrent training LOFT and a three-legged scenario used for the evaluation are highlighted. The test guidelines set up and the questionnaires sent to crew member participants are examined.

Jensen, D.↗

Update on CMH-17 Volume 5: Ceramic Matrix Composites

CMC components are projected to enter service in commercial aircraft in 2016. A wide range of issues must be addressed prior to certification of this hardware. The Composite Materials Handbook-17, Volume 5 on ceramic matrix composites is being revised to support FAA certification of CMCs for hot structure and other elevated temperature applications. The handbook supports the development and use of CMCs through publishing and maintaining proven, reliable engineering information and standards that have been thoroughly reviewed. Volume 5 will contain detailed sections describing CMC materials processing, design analysis guidelines, testing procedures, and data analysis and acceptance. A review of the status of and plans for two of these areas, which are being addressed by the M and P Working Group and the Testing Working Group, will be presented along with a timeline for the preparation of CMH-17, Volume 5.

design↗

CMH-17 Volume 5 Ceramic Matrix Composites

A wide range of issues must be addressed during the process of certifying CMC (ceramic matrix composite) components for use in commercial aircraft. The Composite Materials Handbook-17, Volume 5, Revision A on ceramic matrix composites has just been revised to help support FAA certification of CMCs for elevated temperature applications. The handbook supports the development and use of CMCs through publishing and maintaining proven, reliable engineering information and standards that have been thoroughly reviewed. Volume 5 contains detailed sections describing CMC materials processing, design analysis guidelines, testing procedures, and data analysis and acceptance. A review of the content of this latest revision will be presented along with a description of how CMH-17, Volume 5 could be used by the FAA (Federal Aviation Administration) and others in the future.

characterization↗