GENERATING PENETRATION RESISTANCE FUNCTIONS WITH A VIRTUAL PENETRATION LABORATORY (VPL): APPLICATIONS TO PROJECTILE PENETRATION AND STRUCTURAL RESPONSE SIMULATIONS

Abstract

A new software package called the Virtual Penetration Laboratory (VPL) has been developed to automatically generate and optimize penetration resistance functions. We have used this VPL code to generate highly "tuned" penetration resistance functions that can distinctly model the penetration trajectory of steel projectiles into rate-independent, elastic-perfectly plastic aluminum targets. Projectiles with arbitrary nose geometry were considered in this example (i.e. conical, ogival, and spherical nose shapes). The penetration resistance of the aluminum target was determined by numerically solving a series of spherical and cylindrical cavity expansion problems. The solution to these cavity expansion problems were obtained with an explicit, dynamic finite element code that accounts for material and geometric nonlinearities. The resulting cavity expansion equations are then transformed to penetration resistance functions using various transformation algorithms, in order to determine an appropriate method to spatially distribute the resisting stresses on the projectile nose. The resulting penetration resistance functions were then used in a penetration trajectory code to predict the actual trajectories observed from a set of similar experiments.