Accession Number : ADA303963

Title :   Investigations of the Ballistic Response of Brittle Materials.

Descriptive Note : Technical rept.,

Corporate Author : SOUTHWEST RESEARCH INST SAN ANTONIO TX

Personal Author(s) : Anderson, Charles E., Jr. ; Walker, James D. ; Lankford, Jim

PDF Url : ADA303963

Report Date : NOV 1995

Pagination or Media Count : 114

Abstract : A multi-faceted study of the ballistic response of brittle materials has been performed to include experimental testing, numerical simulations, constitutive evaluation, and investigation of fundamental material response to high rate loading. Depth-of-penetration tests with and without cover plates investigated the performance of 99.5% pure aluminum oxide tiles to ballistic impact using L/D 10 tungsten heavy alloy projectiles at two impact velocities, nominally 1.5 and 1.8 km/s. Numerical simulations, using the EPIC95 finite element hydrocode, were compared to the results of the experiments. The Johnson-Holmquist II constitutive model was used for the computations. Ballistic tests, conducted by the Ernst-Mach-Institut in Germany, recorded in-situ positions of the nose and tail of the projectile at different times after impact, using flash radiography, in soda lime glass. The experimental arrangement was modified so that the projectile velocity was obtained after exiting a finite-thick glass target. The experimental data are analyzed, and numerical simulations of the experiments were conducted using the Eulerian wavecode CTH. Comparisons between the calculations and the experiments using different computational constitutive models provided insight into the constitutive behavior of the glass. Lastly, an experimental apparatus was designed to investigate the behavior of 99.5% pure alumina under large confinement within a controlled laboratory experiment. A split-Hopkinson pressure bar was used to load the confined specimen at a high rate. Metallurgical examination of the specimen after the test demonstrates large plastic flow within the specimen, with cracks originating at locations where dislocations pile up. (MM)

Descriptors :   *GLASS, *STEEL, *CERAMIC MATERIALS, *BRITTLENESS, *TERMINAL BALLISTICS, PITCH(INCLINATION), YAW, IMPACT, TAIL ASSEMBLIES, PROJECTILES, CRACKS, DAMAGE ASSESSMENT, ELASTIC PROPERTIES, STRAIN RATE, PENETRATION, YIELD STRENGTH, COMPRESSIVE STRENGTH, FRAGMENTS, PLASTIC FLOW, METALLURGY, AUTOFRETTAGE, MICROCRACKING, FLASH RADIOGRAPHY.

Subject Categories : Ceramics, Refractories and Glass
      Properties of Metals and Alloys
      Ballistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE