RICOCHET OF DEFORMING PROJECTILES FROM DEFORMING PLATES

Summary-- Ricochet means rebound of a striker from the impacted surface (or penetration i to a medium along a curved trajectory emerging through the impacted surface with a residual velocity). Changes in direction, velocity and rotational motion of the penetrator a e due to several mechanisms. These include release of stored elastic impact energy; influence of surfaces, material interfaces and impact deformations in the target on the magnitude and direction of the resisting force during impact; resistance tomotion due to drag and friction. The subject i,; of interest due to the need to establish safety zones and to design containment s ructures to guard against failure of rapidly moving machine parts, to protect outer components of space vehicles from the energetic debris spray resulting from oblique hypervelocity impact and to reconstruct bullet trajectories in forensic engineering. This paper contrasts two-dimensional p ane strain calculations of ricochet with fully three-dimensinnal simulations performed with Apollo, a three-dimensional L grangian finite element code for impact and explosive loading problems et up exclusively on personal computers and workstations. While some useful information can be extracted from plane strain calculations regarding the early stages of impact, the use of two-dimensional calculations to simulate fully three-dimensional phenomena with long response times (up to the millisecond regime) results in gross overestimation f deflections and is inherently dangerous. Copyrigh