Normal impact of blunt projectiles on moving targets: Analytical considerations

An analytical model for the normal impact of blunt, cylindrical and undeformable projectiles on thin metallic targets moving in a plane normal to the initial bullet trajectory has been developed. This analysis is intended to depict the principal phenomena that occur when such a projectile strikes the center of a circular plate mounted at the end of an arm rotating about the other end at constant angular velocity. The first step in the simulation constructions of the construction of a three-stage plugging process involving plastic wave propagation, joint projectile/target motion and tensile failure designed for impact on a stationary plate, using a membrane theory for the target response. This axisymmetric representation was then applied to moving targets by employment of impulse-momentum laws. Petaling failure was portrayed by an upper-bound plasticity approach, while projectile motion was described by rigid-body dynamics. The principal assumption inherent in this representation were guided by geometric considerations and observations from tests described in a companion paper.

Model evaluation was performed for several cases of projectile and target speed combinations. Relevant solutions were compared with results from corresponding experiments. In general, good correlation were obtained; discrepancies could be attributed to the effect of features that had not been incorporated in the model.