Numerical investigation on the dynamic behavior of advanced ceramics

Abstract

This paper studies the dynamic behavior of advanced ceramics by a finite element model. It implements the direct simulation of fracture and fragmentation together with a mixed-mode cohesive law to describe the fracture process. In particular, we simulate dynamic Brazilian tests performed with a Hopkinson bar, at strain rates ranging from 65 to 89 s −1, on six different materials: three kinds of alumina with different average grain sizes and degrees of purity, a blend of alumina and zirconia, silicon carbide and boron carbide. The rate dependence of the results emerges explicitly from the calculations, thanks both to the inertia attendant to the fracture process, and to the time effect provided by the cohesive law. Indeed, the simulations give accurate values for the dynamic strength of the six ceramics under study. The simulations also predict the main features of the crack pattern.