Theoretical penetration of hypervelocity projectiles into massive targets

Abstract

A model of the penetration of a hypervelocity projectile into a massive target is formulated, and a quasi-theoretical technique for predicting the penetration is developed. It is assumed that 1) the projectile is significantly deformed immediately after impact by the initial shock wave and subsequent expansion waves, and 2) after the initial impact, the deformed projectile is retarded by a pressure on its face resulting from weak waves. The equation of projectile motion is integrated to obtain the depth of penetration. The resulting theoretical penetration is shown to be in agreement with experimental data. Nomenclature C = weak plastic wave speed, constant c = weak plastic wave speed, variable (c) == average wave speed D = projectile diameter K = penetration coefficient L = projectile length p = pressure on projectile-target interface P = penetration depth from face of target S = shock constant t = time after impact u = speed of projectile-target interface U = shock speed v = speed of projectile center of mass V = impact speed Vf = (<rvt/KPtCt)[l+(ptCt/pPCp)] w = material speed x = depth of projectile-target interface z — depth from target surface p — density a — material strength