Normal penetration of an eroding projectile into an elastic-plastic target

The main objective of the present work is to describe normal penetration of a deformable projectile into an elastic-plastic target. The force imposed on the projectile by the target is generally a complex function of the stre ngth of the target material, the projectile velocity, its diameter and shap e, as well as the instantaneous penetration depth. When this force exceeds a certain critical value the projectile begins to deform. At moderate-to-hi gh values of the impact velocity, the projectile's tip material flows plast ically with large deformations causing the formation of a mushroom-like con figuration. This process is accompanied by erosion of the projectile materi al. In the rear ("elastic") part of the projectile the deformations remain small and the region can be approximated as a rigid body being decelerated by the projectile's yield stress. The general model allows one to predict t he penetration depth, the projectile's eroded length and the crater diamete r. It has been shown that in the limit of very high impact velocities the p resent model reduces to the well-known form of the hydrodynamic theory of s haped-charge jets. Also, a simplified asymptotic formula for the crater rad ius has been derived which includes the effect of the target's yield stress and compares well with experimental data for very high impact velocities. (C) 2001 Elsevier Science Ltd. All rights reserved.