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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 109 records · Page 6

Department of Physics' Involvement of the Impact Testing Project of the High Speed Civil Transport Program (HSCT)

The project involved the impact testing of a kevlar-like woven polymer material, PBO. The purpose was to determine whether this material showed any promise as a lightweight replacement material for jet engine fan containment. The currently used metal fan containment designs carry a high drag penalty due to their weight. Projectiles were fired at samples of PBO by means of a 0.5 inch diameter Helium powered gun. The Initial plan was to encase the samples inside a purpose-built steel "hot box" for heating and ricochet containment. The research associate's responsibility was to develop the data acquisition programs and techniques necessary to determine accurately the impacting projectile's velocity. Beyond this, the Research Associate's duties include any physical computations, experimental design, and data analysis necessary.

VonMeerwall, Ernst D.↗

Impact testing of textile composite materials

The objectives of this report were to evaluate the impact damage resistance and damage tolerance of a variety of textile composite materials. Static indentation and impact tests were performed on the stitched and unstitched uniweave composites constructed from AS4/3501-6 Carbon/Epoxy with a fiberglass yarn woven in to hold the fibers together while being stitched. Compression and tension were measured after the tests to determine the damage resistance, residual strength and the damage tolerance of the specimens.

Portanova, Marc↗

Numerical Validation of Composite Panel Impact Tests

Researchers have met the challenge of modeling impact events involving composite targets for a variety of applications in a variety of ways. In this paper, the theory and implementation details of an orthotropic visco-elastic-visco-plastic material model with strain rate dependence are discussed. The model is driven by experimental data from quasi-static as well as high strain rate tests, and the data is used in defining the deformation, damage and failure sub-models. Validation data is generated by shooting a hollow 50 g Al-2024 projectile at different velocities against a flat panel target made of unidirectional composite material in a 16-ply [(0/90/45/-45)_(2)]_(S) layup. Explicit dynamic finite element analyses of four high speed tests involving one contained (projectile rebounded) and three uncontained (projectile penetrated) impact tests show that the developed material model and modeling techniques yield reasonable and acceptable predictions.

Orthotropic Composite↗

Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems: Ballistic Impact Testing - Part 2

Under the Federal Aviation Administration's Airworthiness Assurance Center of Excellence and the Aircraft Catastrophic Failure Prevention Program, National Aeronautics and Space Administration Glenn Research Center collaborated with Arizona State University, Honeywell Engines, Systems and Services, and SRI International to develop improved computational models for designing fabric-based engine containment systems. In the study described in this report, ballistic impact tests were conducted on layered dry fabric rings to provide impact response data for calibrating and verifying the improved numerical models. This report provides data on projectile velocity, impact and residual energy, and fabric deformation for a number of different test conditions.

ZYLON↗

Hypervelocity impact testing of Shuttle Orbiter thermal protection system tiles

Results are presented from a series of 22 hypervelocity impact tests carried out on the thermal protection system (TPS) for the Shuttle Orbiter. Both coated and uncoated low-density (0.14 g/cu cm) LI-900 and high-density (0.35 g/cu cm) LI-2200 tiles were tested. The results are used to develop the penetration and damage correlations which can be used in meteoroid and debris hazard analyses for spacecraft with a ceramic tile TPS. It is shown that tile coatings act as a 'bumper' to fragment the impacting projectile, with thicker coating providing increased protection.

Christiansen, Eric L.↗

Elemental Water Impact Test: Phase 2 36-Inch Aluminum Tank Head

Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. EWIT Phase 2 featured a 36-inch aluminum tank head. The tank head was outfitted with one accelerometer, twelve pressure transducers, three string potentiometers, and four strain gages. The tank head was dropped from heights of 1 foot and 2 feet. The focus of this report is the correlation of analytical models against test data. As a measure of prediction accuracy, peak responses from the baseline LS-DYNA model were compared to peak responses from the tests.

Vassilakos, Gregory J.↗

Support of Adhesion Mechanisms in Al 2 O 3 Aerosol Deposition Through Laser-Induced Particle Impact Testing

Aerosol deposition (AD) is a kinetic spray process capable of depositing ceramic coatings at room temperature, but AD process development is generally a laborious exploration of a large process parameter space. Here, this paper presents a case study investigating whether laser-induced particle impact testing (LIPIT) could be applied to expedite development of an alumina (Al 2 O 3 ) coating on nickel (Ni): Specifically, whether LIPIT measurements could predict critical velocities of adhesion on Ni and Al 2 O 3 , and the effect of ball milling the Al 2 O 3 powder. Because LIPIT has a diffraction-limited lower bound on imageable particle size, the usefulness of Al 2 O 3 powder agglomerates as a proxy for single particles was additionally studied. Overall, LIPIT measurements and AD sprays agreed that ball milling dramatically improves adhesion. Additionally, LIPIT measurements of critical velocity of adhesion of Al 2 O 3 powder agglomerates on Ni and Al 2 O 3 substrates (150 meters per second [m/s] and 250 m/s, respectively) quantitatively agreed with predictions from a previously published model based on picoindentation and molecular dynamics simulations. Together, these findings support the established hypothesis that Al 2 O 3 adheres via a dislocation-mediated mechanism in AD, that Al 2 O 3 powder agglomerates adhere as individual constituent particles rather than collectively, and that, for this case study, LIPIT measurements were predictive of AD process parameters.

Al2O3↗

Hypervelocity impact testing of L-band truss cable meteoroid shielding on Skylab

A series of tests was performed to determine the protection provided by the L-band truss cable meteoroid shielding installed on Skylab space station at space environment temperatures of minus 180 F. The damage sustained when three test specimens were impacted by spherical projectiles at hypersonic speed was investigated. It is concluded that the L-band truss cable meteoroid shielding provides adequate protection at the indicated temperature.

Jex, D. W.↗

Fixture For Compression-After-Impact Tests Of Thin Specimens

Special fixture holds specimen of laminated composite material in 20-klb (89-kN) or larger load frame for compression-after-impact test. In preparation for test, specimen damaged by dropping weight on it at known kinetic energy. During test, specimen loaded in compression, and load measured, until specimen fails. Measurement data used to characterize compressive strength of specimen after impact important indicator of ability of structural components made of composite material to tolerate damage. Tests give more-realistic measures of tolerance to damage.

Nettles, Alan T.↗

Advanced Crew Escape Suits (ACES): Particle Impact Test

NASA Johnson Space Center (JSC) requested NASA JSC White Sands Test Facility to assist in determining the effects of impaired anodization on aluminum parts in advanced crew escape suits (ACES). Initial investigation indicated poor anodization could lead to an increased risk of particle impact ignition, and a lack of data was prevalent for particle impact of bare (unanodized) aluminum; therefore, particle impact tests were performed. A total of 179 subsonic and 60 supersonic tests were performed with no ignition of the aluminum targets. Based on the resulting test data, WSTF found no increased particle impact hazard was present in the ACES equipment.

Rosales, Keisa R.↗

Impact Testing Theories and Techniques Employed at the TA-III Mechanical Shock Complex

We present theories and techniques to support safe, predictable, and efficient impact testing at the Sandia National Laboratories TA-III Mechanical Shock Complex (MSC), located in Building 6570. The two testing instruments used at the MSC are the 20-inch actuator, which is a launcher that propels sleds down an indoor track, and an indoor 6-in bore compressed-gas powered cannon. The theories and techniques presented derive from basic mechanical engineering principles but are significantly informed and validated by testing experience at the MSC.

42 ENGINEERING↗

Results of Two-Stage Light-Gas Gun Development Efforts and Hypervelocity Impact Tests of Advanced Thermal Protection Materials

Gun development efforts to increase the launching capabilities of the NASA Ames 0.5-inch two-stage light-gas gun have been investigated. A gun performance simulation code was used to guide initial parametric variations and hardware modifications, in order to increase the projectile impact velocity capability to 8 km/s, while maintaining acceptable levels of gun barrel erosion and gun component stresses. Concurrent with this facility development effort, a hypervelocity impact testing series in support of the X-33/RLV program was performed in collaboration with Rockwell International. Specifically, advanced thermal protection system materials were impacted with aluminum spheres to simulate impacts with on-orbit space debris. Materials tested included AETB-8, AETB-12, AETB-20, and SIRCA-25 tiles, tailorable advanced blanket insulation (TABI), and high temperature AFRSI (HTA). The ballistic limit for several Thermal Protection System (TPS) configurations was investigated to determine particle sizes which cause threshold TPS/structure penetration. Crater depth in tiles was measured as a function of impact particle size. The relationship between coating type and crater morphology was also explored. Data obtained during this test series was used to perform a preliminary analysis of the risks to a typical orbital vehicle from the meteoroid and space debris environment.

Cornelison, C. J.↗

Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity

An investigation of a 1/6-scale dynamic model has been made to develop and evaluate a technique for conducting full-scale landing-impact tests at simulated lunar gravity. Landings were made at touchdown pitch attitudes of -15 degrees, 0 degrees, and 15 degrees. All landings were made with two gear pads forward and at a roll attitude of 0 degrees. Both roll and yaw attitudes were constrained. Vertical landing speed was varied from 5 to 15 feet per second (1.5 to 4.6 m/s) and horizontal speed was varied from 0 to 10 feet per second (0 to 3.0 m/s). Most of the landings were made at a vertical and horizontal speed of 10 feet per second or 3.0 m/s (45 degree flight-path angle) while pitch attitude and surface characteristics, friction and topography, were varied. These parameters were investigated with the free-body earth-gravity and the simulated lunar-gravity test techniques. The landings were made at a model mass corresponding to a full-scale lunar weight (force due to gravity) of 1,440 pounds (6.41 kN) or an earth weight of 8,640 pounds (38.4 kN).

TESTS↗

A Comparison of Quasi-Static Indentation and Drop-Weight Impact Testing on Carbon-Epoxy Laminates

The project had two objectives: 1) The primary objective was to characterize damage tolerance of composite materials. To accomplish this, polymer matrix composites were to be subjected to static indentation as well as low-velocity impacts and the results analyzed. 2) A second objective was to investigate the effects of laser shock peening on the damage tolerance of aerospace materials, such as aluminum alloys, in terms of crack nucleation and crack propagation. The impact testing was proposed to be performed using a Dynatup drop tower. The specimens were to be placed over a square opening in a steel platen and impacted with a hemispherical tup. The damage was to be characterized in the laminate specimens. The damage tolerance of aerospace alloys was to be studied by conducting fatigue tests on aluminum alloy specimens with prior shock peening treatment. The crack length was to be monitored by a microscope and the crack propagation rate, da/dN, determined.

Prabhakaran, R.↗

Hypervelocity Impact Testing of Nickel Hydrogen Battery Cells

Nickel-Hydrogen (Ni/H2) battery cells have been used on several satellites and are planned for use on the International Space Station. In January 1992, the NASA Lewis Research Center (LeRC) conducted hypervelocity impact testing on Ni/H2 cells to characterize their failure modes. The cell's outer construction was a 24 mil-thick Inconel 718 pressure vessel. A sheet of 1.27 cm thick honeycomb was placed in front of the battery cells during testing to simulate the on-orbit box enclosure. Testing was conducted at the NASA White Sands Test Facility (WSTF). The hypervelocity gun used was a 7.6 mm (0.30 caliber) two-stage light gas gun. Test were performed at speeds of 3, 6, and 7 km/sec using aluminum 2017 spherical particles of either 4.8 or 6.4 mm diameter as the projectile. The battery cells were electrically charged to about 75 percent of capacity, then back-filled with hydrogen gas to 900 psi simulating the full charge condition. High speed film at 10,000 frames/sec was taken of the impacts. Impacts in the dome area (top) and the electrode area (middle) of the battery cells were investigated. Five tests on battery cells were performed. The results revealed that in all of the test conditions investigated, the battery cells simply vented their hydrogen gas and some electrolyte, but did not burst or generate any large debris fragments.

Frate, David T.↗

Measurement Techniques for Hypervelocity Impact Test Fragments

The ability to classify the size and shape of individual orbital debris fragments provides a better understanding of the orbital debris environment as a whole. The characterization of breakup fragmentation debris has gradually evolved from a simplistic, spherical assumption towards that of describing debris in terms of size, material, and shape parameters. One of the goals of the NASA Orbital Debris Program Office is to develop high-accuracy techniques to measure these parameters and apply them to orbital debris observations. Measurement of the physical characteristics of debris resulting from groundbased, hypervelocity impact testing provides insight into the shapes and sizes of debris produced from potential impacts in orbit. Current techniques for measuring these ground-test fragments require determination of dimensions based upon visual judgment. This leads to reduced accuracy and provides little or no repeatability for the measurements. With the common goal of mitigating these error sources, allaying any misunderstandings, and moving forward in fragment shape determination, the NASA Orbital Debris Program Office recently began using a computerized measurement system. The goal of using these new techniques is to improve knowledge of the relation between commonly used dimensions and overall shape. The immediate objective is to scan a single fragment, measure its size and shape properties, and import the fragment into a program that renders a 3D model that adequately demonstrates how the object could appear in orbit. This information would then be used to aid optical methods in orbital debris shape determination. This paper provides a description of the measurement techniques used in this initiative and shows results of this work. The tradeoffs of the computerized methods are discussed, as well as the means of repeatability in the measurements of these fragments. This paper serves as a general description of methods for the measurement and shape analysis of orbital debris.

Hill, Nicole E.↗