Numerical Study of Damage Propagation and Dynamic Fracture in Sapphire

Abstract : Sapphire, a single crystal of aluminum oxide, is of interest to U.S. Army and one of the candidate materials for use as the hardstrike face of a transparent laminated armor. Strassburger et al studied monolithic single crystal sapphire plates (100 mm x100 mm x 10 mm) in crystallographically controlled directions, such as the (0001) basal plane, r-plane (1011) rhombohedralplane and (1010) prismatic plane, impacted at about 450 m/s with both steel solid cylinders and spheres. The edge-on impact(EOI) ballistic behavior of these plates is simulated using the non-linear AUTODYN commercial package by using threedimensional,180 degrees (reflective) modeling and simulation. This study reports on the ability and the modification ofexisting strength and failure material models of Al2O3 to be used as sapphire models for duplication of the experimentalfracture and wave propagation in sapphire of different crystal orientation with respect to the line of impact.