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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1997

Joint US/Russian testing for track propagation

The power thresholds below which track propagation does not occur were determined in Russian spacecraft. The tests were performed in air and vacuum with direct current on different insulation and sample configurations. The examined wire insulations included 100 percent polyimide, modified polyimide-based insulations containing 7 to 8 percent and 100 percent polytetrafluoroethylene. The wires were tested in configurations consisting of seven-wire bundles. The results indicated that the track propagation thresholds were lower in vacuum than in air.

Hirsch, David↗
DOE OSTI2024

ACCELERATING MICROREACTOR DEVELOPMENT AND DEPLOYMENT THROUGH JOINT PUBLIC TEST BEDS AND PRIVATE ADVANCED REACTOR DEVELOPMENT

The United States Department of Energy (DOE) has funded the National Reactor Innovation Center (NRIC) to accelerate the development and commercialization of small modular reactors and other advanced reactor technologies. As part of this effort NIRC is building two strategic assets at the Idaho National Laboratory (INL) to facilitate public-private partnerships for the development and testing of advanced nuclear microreactors and Small Modular Reactors (SMR). One will provide a safe, secure, and affordable location for High-Assay Low Enriched Uranium (HALEU) fueled reactors and a second for Highly Enriched Uranium (HEU) fueled reactors. Together these testbeds fill a nuclear testing infrastructure gap. The availability of such comprehensive testing facilities at the national labs eliminates the significant financial and operational burdens associated with each developer building and licensing their own test facilities. Consequently, this approach will not only accelerate technological innovation and reduce time-to-market for advanced nuclear solutions but it also underscores the DOE's commitment to fostering an ecosystem where nuclear energy will thrive as a clean, reliable, and efficient source of power. The Demonstration of Microreactor Experiments (DOME) and Laboratory for Operations and Testing in the United States (LOTUS) have planned availability in 2026, and 2027 respectively.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Utah FORGE: Results of Direct Shear Tests on Saturated Joints in Sierra White Granite

This dataset includes an Excel file with the results of direct shear tests to investigate the mechanical and geophysical response of saturated joints. Tests were conducted on induced tension-fractured Sierra White granite joints in a custom water pressurized chamber. The preparation of granite joints is summarized in the PDF file. The PDF file also includes a description of the direct shear tests, experimental procedure, and results.

15 GEOTHERMAL ENERGY↗
NASA NTRS1990

Evaluation of two transport aircraft and several ground test vehicle friction measurements obtained for various runway surface types and conditions. A summary of test results from joint FAA/NASA Runway Friction Program

Tests with specially instrumented NASA Boeing 737 and 727 aircraft together with several different ground friction measuring devices were conducted for a variety of runway surface types and conditions. These tests are part of joint FAA/NASA Aircraft/Ground Vehicle Runway Friction Program aimed at obtaining a better understanding of aircraft ground handling performance under adverse weather conditions and defining relationships between aircraft and ground vehicle tire friction measurements. Aircraft braking performance on dry, wet, snow and ice-covered runway conditions is discussed as well as ground vehicle friction data obtained under similar runway conditions. For a given contaminated runway surface condition, the correlation between ground vehicles and aircraft friction data is identified. The influence of major test parameters on friction measurements such as speed, test tire characteristics, type and amount of surface contaminant, and ambient temperature are discussed. The effect of surface type on wet friction levels is also evaluated from comparative data collected on grooved and ungrooved concrete and asphalt surfaces.

Yager, Thomas J.↗
NASA NTRS1991

Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures.

Haigh, S. J.↗
NASA NTRS1991

Demonstration of Hazardous Hypervelocity Test Capability

NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) participated in a joint test program with NASA JSC Hypervelocity Impact Research Laboratory (HIRL) to determine if JSC was capable of performing hypervelocity impact tests on hazardous targets. Seven pressurized vessels were evaluated under hypervelocity impact conditions. The vessels were tested with various combinations of liquids and gasses at various pressures. Results from the evaluation showed that vessels containing 100-percent pressurized gas sustained more severe damage and had a higher potential for damaging nearby equipment, than vessels containing 75-percent liquid, 25-percent inert pressurized gas. Two water-filled test vessels, one of which was placed behind an aluminum shield, failed by bulging and splitting open at the impact point; pressure was relieved without the vessel fragmenting or sustaining internal damage. An additional water-filled test vessel, placed a greater distance behind an aluminum shield, sustained damage that resembled a shotgun blast, but did not bulge or split open; again, pressure was relieved without the vessel fragmenting. Two test vessels containing volatile liquids (nitro methane and hydrazine) also failed by bulging and splitting open; neither liquid detonated under hypervelocity test conditions. A test vessel containing nitrogen gas failed by relieving pressure through a circular entry hole; multiple small penetrations opposite the point of entry provided high velocity target debris to surrounding objects. A high-pressure oxygen test vessel fragmented upon impact; the ensuing fire and high velocity fragments caused secondary damage to surrounding objects. The results from the evaluation of the pressurized vessels indicated that JSC is capable of performing hypervelocity impact tests on hazardous targets.

Rodriquez, Karen M.↗
NASA NTRS2013

Lap Shear Testing of Candidate Radiator Panel Adhesives

During testing of a subscale radiator section used to develop manufacturing techniques for a full-scale radiator panel, the adhesive bonds between the titanium heat pipes and the aluminum face sheets failed during installation and operation. Analysis revealed that the thermal expansion mismatch between the two metals resulted in relatively large shear stresses being developed even when operating the radiator at moderate temperatures. Lap shear testing of the adhesive used in the original joints demonstrated that the two-part epoxy adhesive fell far short of the strength required. A literature review resulted in several candidate adhesives being selected for lap shear joint testing at room temperature and 398 K, the nominal radiator operating temperature. The results showed that two-part epoxies cured at room and elevated temperatures generally did not perform well. Epoxy film adhesives cured at elevated temperatures, on the other hand, did very well with most being sufficiently strong to cause yielding in the titanium sheet used for the joints. The use of an epoxy primer generally improved the strength of the joint. Based upon these results, a new adhesive was selected for the second subscale radiator section.

Ellis, David↗
NASA NTRS1990

An apparatus for bearing-bypass testing of bolted joints

A dual-control test system measuring the strength of graphite/epoxy specimens under tension and compression for a wide range of bearing-bypass load ratios is presented. The bearing-bypass strengths of single-fastener specimens are measured for damage onset and ultimate failure and are plotted against one another. The results indicate that an initiated damage grows to failure in the same mode for most cases. However, if the damage is initiated in the compression-reacted-bearing mode, the specimens fail in the offset-compression mode. It is concluded that this type of transition can occur in multi-fastener joints under compression and complicate the strength predictions.

Crews, J. H., Jr.↗
NASA NTRS1974

Mechanical properties of eutectic bonded boron aluminum

Results are presented of extensive testing recently completed on boron-aluminum composites to determine mechanical property data for structural design and analysis. Average property data and associated test methods are given for unidirectional and cross plied laminates at room temperature and 600 F. Results from crippling tests of hat-shaped stringers and mechanical fastener joint tests of laminates containing titanium interleaves are also presented. Compared to aluminum which has approximately same density, tests show that boron-aluminum loaded in compression is 4 1/2 times stronger and 3 1/2 times stiffer. When loaded in tension it is 2 times stronger and 3 times stiffer.

Bohlmann, R. E.↗
NASA NTRS1998

Effect of Installation of Mixer/Ejector Nozzles on the Core Flow Exhaust of High-Bypass-Ratio Turbofan Engines

The aerospace industry is currently investigating the effect of installing mixer/ejector nozzles on the core flow exhaust of high-bypass-ratio turbofan engines. This effort includes both full-scale engine tests at sea level conditions and subscale tests in static test facilities. Subscale model tests are to be conducted prior to full-scale testing. With this approach, model results can be analyzed and compared with analytical predications. Problem areas can then be identified and design changes made and verified in subscale prior to committing to any final design configurations for engine ground tests. One of the subscale model test programs for the integrated mixer/ejector development was a joint test conducted by the NASA Lewis Research Center and Pratt & Whitney Aircraft. This test was conducted to study various mixer/ejector nozzle configurations installed on the core flow exhaust of advanced, high-bypass-ratio turbofan engines for subsonic, commercial applications. The mixer/ejector concept involves the introduction of largescale, low-loss, streamwise vortices that entrain large amounts of secondary air and rapidly mix it with the primary stream. This results in increased ejector pumping relative to conventional ejectors and in more complete mixing within the ejector shroud. The latter improves thrust performance through the efficient energy exchange between the primary and secondary streams. This experimental program was completed in April 1997 in Lewis' CE-22 static test facility. Variables tested included the nozzle area ratio (A9/A8), which ranged from 1.6 to 3.0. This ratio was varied by increasing or decreasing the nozzle throat area, A8. Primary nozzles tested included both lobed mixers and conical primaries. These configurations were tested with and without an outer shroud, and the shroud position was varied by inserting spacers in it. In addition, data were acquired with and without secondary flow.

Harrington, Douglas E.↗
NASA NTRS1995

NASA and CD Radio's TDRSS industrial test program

The National Aeronautics and Space Administration (NASA) has embarked on a joint test program with CD Radio Inc. The program will demonstrate spatial diversity techniques in support of industrial development of a new satellite direct broadcast national radio service called Satellite Radio. Satellite Radio will operate in the FCC approved frequency band 2310-2360 MHz which is close to NASA's Tracking and Data Relay System (TDRSS) satellites' high power transmit frequency near 2110 MHz. The cooperative test program in which NASA provides use of a TDRSS satellite and CD Radio provides the measurement equipped vehicle is described as well as its current status. Some initial measurement data are presented.

Briskman, Robert D.↗
NASA NTRS1980

Preliminary Arc-Jet tests of ablator/RSI joints in simulated space shuttle ascent and entry heating

Five ablator/RSI panels were tested in simulated Shuttle heating conditions to determine heat pulse effects on the ablator and the ablator/RSI joints. Two of the panels were subjected to both ascent and entry heating. The other three panels were subjected to entry heating only. The double-pulse heating (ascent plus entry) had no significant effect on char-layer integrity. Evaluation of the effects of entry heating on the ablator/RSI joints was difficult because, with the panel configuration used, severe pressure gradients developed within some of the joints during testing causing hot-gas flow through the joints. In joints where pressure leaks apparently did not develop, temperatures within the joints were reasonable compared to ablator and RSI back surface temperatures.

Brewer, W. D.↗
DOE OSTI2023

Mitigating Corrosion in Mg Sheet in Conjunction with a Sheet-Joining Method that Satisfies Structural Requirements within Sub-assemblies

This work was undertaken as a LightMAT project funded by the DOE-Vehicles Technology Office. The goal of this work was to develop corrosion protection strategies that simultaneously mitigate corrosion and achieve Class-A surface finish for Mg components in automotive applications. While automotive metals such as steel and aluminum are protected against corrosion through a variety of coating schemes/packages, the efficacy of these existing coating schemes for Mg and Mg- joints is not clear and needs to be determined. Therefore, five commercially available coating schemes and two joining techniques (riveting and Arplas resistance spot welding) were evaluated. The corresponding individual Mg sheet coupons or Mg/Mg joint test coupons were provided by Magna that were then corrosion tested at PNNL using ASTM B117 procedure. The microstructures and mechanical properties of the coupons were analyzed to determine the effectiveness of the joining and corrosion mitigation strategies. Of the coating schemes evaluated, Henkel Bonderite MgC 2.0 pre-treatment + E-coat showed the best corrosion protection and surface finish for individual Mg coupons and Arplas resistance spot welded coupons. However, the strength of Mg/Mg welded joint was reduced after corrosion testing due to some corrosion at the weld nugget. Mg/Mg rivet joints in conjunction with Chemetall oxisilan pre-treatment + polyurethane coating showed good corrosion resistance and some discoloration on the surface finish. Coating schemes comprising pre-treatment with Alodine 5200 + E-coat or Bonderite 1455 + polyurethane coating, in conjunction with Al rivet joints, showed significant corrosion and extensive discoloration of the surface. We anticipate that the results from this work will provide useful guidance to the automotive industry in selecting the appropriate combinations of corrosion protection coatings and joining techniques to fabricate light-weight Mg-based automotive components.

36 MATERIALS SCIENCE↗
NASA NTRS1923

Tests on riveted joints in sheet duralumin

In making tension tests, the slippage of the joints was noted at three points across each joint. In addition, stress strain curves were obtained for plain tension specimens, and a chemical analysis was made of the sheet.

Rettew, H F↗
NASA NTRS1992

Power assist EVA glove development

Structural modeling of the EVA glove indicates that flexibility in the metacarpophalangeal (MCP) joint can be improved by selectively lowering the elasticity of the glove fabric. Two strategies are used to accomplish this. One method uses coil springs on the back of the glove to carry the tension in the glove skin due to pressurization. These springs carry the loads normally borne by the glove fabric, but are more easily deformed. An active system was also designed for the same purpose and uses gas filled bladders attached to the back of the EVA glove that change the dimensions of the back of the glove and allow the glove to bend at the MCP joint, thus providing greater flexibility at this joint. A threshold control scheme was devised to control the action of the joint actuators. Input to the controller was provided by thin resistive pressure sensors placed between the hand and the pressurized glove. The pressure sensors consist of a layer of polyester film that has a thin layer of ink screened on the surface. The resistivity of the ink is pressure dependent, so an extremely thin pressure sensor can be fabricated by covering the ink patch with another layer of polyester film and measuring the changing resistance of the ink with a bridge circuit. In order to sense the force between the hand and the glove at the MCP joint, a sensor was placed on the palmar face of the middle finger. The resultant signal was used by the controller to decide whether to fill or exhaust the bladder actuators on the back of the glove. The information from the sensor can also be used to evaluate the effectiveness of a given control scheme or glove design since the magnitude of the measured pressures gives some idea of the torque required to bend a glove finger at the MCP joint. Tests of this actuator, sensor, and control system were conducted in an 57.2 kPa glove box by performing a series of 90 degree finger bends with a glove without an MCP joint assembly, a glove with the coil spring assembly, and with the four fingered actuated glove. The tests of these three glove designs confirm the validity of the model.

Main, John A.↗
NASA NTRS1997

Test Report - Fault Current Through Graphite Filament Reinforced Plastic

Tests were performed to determine the damage to samples of composite material when a current carrying wire is shorted to the surface of the composite material, and to determine whether enough current can flow through the material to blow a fuse before damage can occur. Fault current tests were performed on samples of graphite epoxy materials. Samples consisted of six layers of IM7 graphite fiber mat in Hercules 8552 epoxy resin. A variable power supply provided up to 35 amps of current. The high voltage side of the power supply was attached to a wire at the end of a hinged arm, and the low side was attached to the edge of the sample. To test joints, the return was connected to the edge of one sample, and the high side was shorted to the top of the other sample. Tests show that when current exceeds approximately 5 amps, the graphite glows, and the epoxy melts out at the shorted contact. At higher current levels the epoxy burns. At voltages above 15 volts the epoxy outer coat is easily broken, and fire, flame, and a rise in current occur suddenly. When joints are introduced, resistance is increased, and the maximum current resulting from a short circuit to the graphite epoxy is reduced. This condition can easily result in fault current lower than the circuit breaker limit and higher than the 5 amp ignition level. The shorting contact and the joint become hot spots with melting epoxy, smoke, and fire.

Evans, R. W.↗