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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Hypervelocity impact tests on Space Shuttle Orbiter RCC thermal protection material

It is noted that the Shuttle Orbiter will be more subject to meteoroid impact than previous spacecraft, due to its greater surface area and longer cumulative time in space. The Orbiter structural material, RCC, a reinforced carbon-carbon laminate with a diffused silicon carbide coating, is evaluated in terms of its resistance to hypervelocity impact. It was found that the specimens (disks with a mass of 34 g and a thickness of 5.0 mm) were cratered only on the front surface when the impact energy was 3 J or less. At 3 J, a trace of the black carbon interior was exposed. The specimens were completely penetrated when the energy was 34 J or greater.

Humes, D. H.↗
NASA NTRS2016

Suited and Unsuited Hybrid III Impact Testing and Finite Element Model Characterization

NASA spacecraft design requirements for occupant protection are a combination of the Brinkley Dynamic Response Criteria and injury assessment reference values (IARV) extracted from anthropomorphic test devices (ATD). For the ATD IARVs, the requirements specify the use of the 5th percentile female Hybrid III and the 95th percentile male Hybrid III. Each of these ATDs is required to be fitted with an articulating pelvis (also known as the aerospace pelvis) and a straight spine. The articulating pelvis is necessary for the ATD to fit into spacecraft seats, while the straight spine is required as injury metrics for vertical accelerations are better defined for this configuration. Sled testing of the Hybrid III 5th Percentile Female Anthropomorphic Test Device (ATD) was performed at Wright-Patterson Air Force Base (WAPFB). Two 5th Percentile ATDs were tested, the Air Force Research Lab (AFRL) and NASA owned Hybrid III ATDs with aerospace pelvises. Testing was also conducted with a NASA-owned 95th Percentile Male Hybrid III with aerospace pelvis at WPAFB. Testing was performed using an Orion seat prototype provided by Johnson Space Center (JSC). A 5-point harness comprised of 2 inch webbing was also provided by JSC. For suited runs, a small and extra-large Advanced Crew Escape System (ACES) suit and helmet were also provided by JSC. Impact vectors were combined frontal/spinal and rear/lateral. Some pure spinal and rear axis testing was also performed for model validation. Peak accelerations ranged between 15 and 20-g. This range was targeted because the ATD responses fell close to the IARV defined in the Human-Systems Integration Requirements (HSIR) document. Rise times varied between 70 and 110 ms to assess differences in ATD responses and model correlation for different impact energies. The purpose of the test series was to evaluate the Hybrid III ATD models in Orion-specific landing orientations both with and without a spacesuit. The results of these tests were used by the NASA Engineering and Safety Center (NESC) to validate the finite element model (FEM) of the Hybrid III 5th Percentile Female ATD. Physical test data was compared to analytical predictions from simulations, and modelling uncertainty factors have been determined for each injury metric. Additionally, the test data has been used to further improve the FEM, particularly in the areas of the ATD preload, harness, and suit and helmet effects.

Lawrence, C.↗
NASA NTRS1994

Hypervelocity Impact Testing of Space Station Freedom Solar Cells

Solar array coupons designed for the Space Station Freedom electrical power system were subjected to hypervelocity impacts using the HYPER facility in the Space Power Institute at Auburn University and the Meteoroid/Orbital Debris Simulation Facility in the Materials and Processes Laboratory at the NASA Marshall Space Flight Center. At Auburn, the solar cells and array blanket materials received several hundred impacts from particles in the micron to 100 micron range with velocities typically ranging from 4.5 to 10.5 km/s. This fluence of particles greatly exceeds what the actual components will experience in low earth orbit. These impacts damaged less than one percent of total area of the solar cells and most of the damage was limited to the cover glass. There was no measurable loss of electrical performance. Impacts on the array blanket materials produced even less damage and the blanket materials proved to be an effective shield for the back surface of the solar cells. Using the light gas gun at MSFC, one cell of a four cell coupon was impacted by a 1/4 inch spherical aluminum projectile with a velocity of about 7 km/s. The impact created a neat hole about 3/8 inch in diameter. The cell and coupon were still functional after impact.

Christie, Robert J.↗
NASA NTRS2001

Hypervelocity Impact Testing of International Space Station Meteoroid/Orbital Debris Shielding Using an Inhibited Shaped Charge Launcher

Engineers at the NASA Johnson Space Center have conducted hypervelocity impact (HVI) performance evaluations of spacecraft meteoroid and orbital debris (M/OD) shields at velocities in excess of 7 km/s. The inhibited shaped charge launcher (ISCL), developed by the Southwest Research Institute, launches hollow, circular, cylindrical jet tips to approximately 11 km/s. Since traditional M/OD shield ballistic limit performance is defined as the diameter of sphere required to just perforate or spall a spacecraft pressure wall, engineers must decide how to compare ISCL derived data with those of the spherical impactor data set. Knowing the mass of the ISCL impactor, an equivalent sphere diameter may be calculated. This approach is conservative since ISCL jet tips are more damaging than equal mass spheres. A total of 12 tests were recently conducted at the Southwest Research Institute (SWRI) on International Space Station M/OD shields. Results of these tests are presented and compared to existing ballistic limit equations. Modification of these equations is suggested based on the results.

Kerr, Justin H.↗
NASA NTRS2018

Dynamic Impact Testing and Model Development in Support of NASA's Advanced Composites Program

The purpose of this presntation is to provide an executive overview of the HEDI effort for NASAs Advanced Composites Program and establish the foundation for the remaining papers to follow in the 2018 SciTech special session NASA ACC High Energy Dynamic Impact. The paper summarizes the work done for the Advanced Composites Program to advance our understanding of the behavior of composite materials during high energy impact events and to advance the ability of analytical tools to provide predictive simulations. The experimental program carried out at GRC is summarized and a status on the current development state for MAT213 will be provided. Future work will be discussed as the HEDI effort transitions from fundamental analysis and testing to investigating sub-component structural concept response to impact events.

Melis, Matthew E.↗
NASA NTRS2018

Dynamic Impact Testing and Model Development in Support of NASA's Advanced Composites Program

The purpose of this paper is to provide an executive overview of the HEDI effort for NASA's Advanced Composites Program and establish the foundation for the remaining papers to follow in the 2018 SciTech special session NASA ACC High Energy Dynamic Impact. The paper summarizes the work done for the Advanced Composites Program to advance our understanding of the behavior of composite materials during high energy impact events and to advance the ability of analytical tools to provide predictive simulations. The experimental program carried out at GRC is summarized and a status on the current development state for MAT213 will be provided. Future work will be discussed as the HEDI effort transitions from fundamental analysis and testing to investigating sub-component structural concept response to impact events.

Melis, Matthew E.↗
NASA NTRS1991

Compression-after-impact testing of thin composite materials

A new method has been devised to test composite specimens as thin as 8 plies and up to 7.6 cm in width for compression strength. This method utilizes a fixture incorporating the best features of the Celanese and IITRI fixtures combined with an antibuckling jig developed at the University of Dayton Research Institute. This new method uses up to 83 percent less material than the most commonly used compression-after-impact technique (which calls for a 48 ply test specimen) and can also be performed on smaller loading frames since a much smaller force is needed to fail the specimen. The thickness of the test specimen can be fabricated to exactly match production part thickness, thus yielding more meaningful results. CAI tests were performed on IM6/3501 carbon/epoxy utilizing this new method. To verify the design, a series of tests were performed in which undamaged specimens were tested using the new fixture and ASTM D 3410-87 (Celanese compression test) and the results compared. The new fixture works well and will be a valuable asset to MSFC's damage tolerance program.

Nettles, Alan T.↗
NASA NTRS1972

A 1055 ft/sec impact test of a two foot diameter model nuclear reactor containment system without fracture

A study to determine the feasibility of containing the fission products of a mobile reactor in the event of an impact is presented. The model simulated the reactor core, energy absorbing gamma shielding, neutron shielding and the containment vessel. It was impacted against an 18,000 pound reinforced concrete block at 1055 ft/sec. The model was significantly deformed and the concrete block demolished. No leaks were detected nor were any cracks observed in the model after impact.

Puthoff, R. L.↗
NASA NTRS1985

Water impact testing of a filament wound case

A lightweight Filament Wound Case (FWC) Solid Rocket Booster (SRB) is being developed by NASA to increase the payload capability of the space shuttle. As with the steel boosters, the current plan is to recover the FWC SRB's after they impact the ocean at 65 to 85 ft/sec. As the boosters enter the ocean (nozzle first) the water moves away from the vehicle creating a cavity, which then collapses on the vehicle, and results in a significant loading event. To understand this loading event, tests were conducted on a quarter scale FWC model to measure cavity collapse pressure distributions, deflected shape and the effects of end conditions and pressure scaling.

Schmidt, A. A.↗
DOE OSTI2024

High Speed Impact Testing of UHMWPE Composite Using Orthogonal Arrays

Abstract Background Ultra high molecular weight polyethylene composites are fiber based composites used in armor applications. While some characterization has been conducted experimentally, this study varies multiple parameters simultaneously to investigate material response under a wide range of conditions. Objective This work focuses on characterizing the response of Dyneema ® HB26 hard laminate composites under high-speed impacts to examine the influence of plate diameter, clamping pressure, and plate spacing on target performance. Additionally, micro Computer Tomography scans are used to nondestructively evaluate the damage evolution in the targets. Methods These scan results are used in concert with more traditional armor performance metrics to evaluate the effect of various parameters using the method of orthogonal array analysis. This technique allows for multiple variables to be investigated in the same test series, saving time and budget while still providing quality results across a range of variables and variable values. Results We conclude that of the parameters investigated, the plate spacing parameter has the largest effect on performance, followed by the plate diameter. Bolt torque was found to not have a significant impact on results, indicating that an edge clamping pressure is not critical to material response. Additionally, by examining the high resolution scans, we can quantify the damage with an effective damage angle and that this angle is a good predictor of performance. Conclusion Finally a damage theory involving the effective bending strength of the plates is discussed as an explanation for all of the results observed in this test series.

Hannah, T. (ORCID:0000000230261362)↗
DOE OSTI2020

GPHS Module Pre-Impact test Temperature Prediction with ANSYS [PowerPoint]

The purpose of the project was to: Develop a finite element thermal model of the General Purpose Heat Source (GPHS) Module loaded with four fueled clads; Perform steady state analysis to validate the thermal model via energy balance; Perform transient thermal analysis to predict clad temperatures at various times; and, Transient model results will be used to inform module soak time needed to reach a desired clad temperature prior to impact.

42 ENGINEERING↗
DOE OSTI2021

Impact Testing and Analysis of Modified Metal Slugs

This report summarizes initial results from a series of gun experiments which were conducted at the DICE facility. The target of these experiments was a modified metal slug composed of a tantalum/tungsten alloy (Ta-10W). The general geometry of the slug was a right circular cylinder with a through-hole cut normal to the cylinder's axis. In all experiments, hardened steel impactors were used, the desired impact velocity was 200 m/s, the slug was preheated to a target temperature of 175° C, photon doppler velocimetry (PDV) was used to measure the projectile velocity before and after impact, and the impact event was recorded with high-speed video. In two of the impacts the slug was oriented perpendicular to the projectile, while in the remaining two it was tilted 8° from normal. Initial high-speed speed video results showed slug failure in the tilted impact case, while the slug survived normal impacts. Recovery fixtures were used to preserve impacted slugs for future postmortem analysis. Discussions are included regarding improvements to potential future experiments involving these slugs.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
NASA NTRS2017

Hypervelocity Impact Testing of Materials for Additive Construction: Applications on Earth, the Moon, and Mars

Additive Construction is the process of building infrastructure such as habitats, garages, roads, berms, etcetera layer by layer (3D printing). The National Aeronautics and Space Administration (NASA) and the United States Army Corps of Engineers (USACE) are pursuing additive construction to build structures using resources available in-situ. Using materials available in-situ reduces the cost of planetary missions and operations in theater. The NASA team is investigating multiple binders that can be produced on planetary surfaces, including the magnesium oxide-based Sorel cement; the components required to make Ordinary Portland Cement (OPC), the common cement used on Earth, have been found on Mars. The availability of OPC-based concrete on Earth drove the USACE to pursue additive construction for base housing and barriers for military operations. Planetary and military base structures must be capable of resisting micrometeoroid impacts with velocities ranging from 11 to 72km/s for particle sizes 200 micrometers or more (depending on protection requirements) as well as bullets and shrapnel with a velocity of 1.036km/s with projectiles 5.66mm diameter and 57.40mm in length, respectively.

Hypervelocity Impact↗