Accession Number : ADA290650

Title :   Robust Algorithms for Penetration Mechanics Problems.

Descriptive Note : Final rept.,

Corporate Author : MISSOURI UNIV-ROLLA

Personal Author(s) : Batra, R. C.

PDF Url : ADA290650

Report Date : OCT 1994

Pagination or Media Count : 52

Abstract : We have studied the punching of a circular cylindrical hole in a steel plate impacted by a long rigid cylindrical rod. The material of the plate has been modeled by the Litonski-Batra constitutive relation, the effect of heat conduction is considered, the contacting surfaces are taken to be smooth, and the mesh is refined adaptively. Subsequent to the initial shock phase of impact during which the deformed plate material protrudes backwards, a plug ahead of the punch extrudes through the plate and a thin shear layer, characterized by the sharp transition of the axial velocity of plate particles, develops. In an attempt to delineate the susceptibility of tungsten and depleted uranium penetrators to adiabatic shear banding, we have investigated the development of shear bands in a rectangular block of these materials deformed in plane strain compression at a nominal strain-rate of 5000/s. Deformations of a quarter of the domain are analyzed. The undeformed region is divided into 10(exp 4) uniform rectangular elements and the yield strength of 300 randomly located elements is lowered by 5%. The numbers and orientations of shear bands are different in these two materials. The shear bands are found to initiate in tungsten at a lower value of the average strain than that in depleted uranium. (MM)

Descriptors :   *ALGORITHMS, *TERMINAL BALLISTICS, *DEPLETED URANIUM, *TUNGSTEN, VISCOPLASTICITY, THERMOMECHANICS, ARMOR, IMPACT, PROJECTILES, DEFORMATION, STRAIN(MECHANICS), STEEL, STRAIN RATE, PENETRATION, PLATES, THERMAL CONDUCTIVITY, RODS, YIELD STRENGTH, HARDNESS, AXIAL LOADS.

Subject Categories : Properties of Metals and Alloys
      Ballistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE