Penetration and Perforation of Thick Metallic Targets under Impact by Missiles

Simple analytical equations are given in this paper to predict the penetration and perforation of thick metallic targets under normal impact by missiles with different nose shapes over a wide range of impact velocities. In the formulation, it is assumed that the deformations are localized and that the impact energy is dissipated only by penetration. It is further assumed that the mean pressure offered by the target materials to resist the missiles consists of two parts. The first is a cohesive quasi-static resistive pressure due to the elastic-plastic deformation of the target materials based upon a cavity expansion formula. The second is a dynamic resistive pressure defined as a velocity-dependent enhancement factor applied to the quasi-static resistance. Equations are derived for predicting the D. O. P. (Depth of Penetration) in the targets and the ballistic limits in the case of perforation. It transpires that the model predictions are in good agreement with experimental data for a wide range of metallic targets struck transversely by missiles with different nose shapes over a wide range of impact velocities.