Crater formation dynamics in long rod (or jet) penetration

Abstract
Szendrei (and others) proposed a model for the dynamics of crater formation in long rod or jet penetration. We ran computer simulations, with AUTODYN2D/Euler, of a strength-less tungsten long rod penetrating an RHA steel target, to check the performance of Szendrei's model. From the simulations, and by comparing simulations to the model, we draw the following conclusions : 1. The basic assumption behind the model that the crater grows radially from the projectile boundary is simplistic. Simulations show that material points on the crater boundary originate from the initial projectile/target interface. 2. Simulations do not confirm the crater dynamics implied by the model. In the model, the crater starts growing at a high velocity that monotonically decreases to zero. In simulations, the radial velocity starts at a low value, reaches a maximum and then decreases asymptotically to zero. 3. The model prediction of the final crater radius underestimates simulation results quite substantially.