Growth of voids in porous ductile materials at high strain rate

Abstract

A hollow-sphere model, with temperature-dependent viscoplastic material response, is developed to investigate the inertial and thermal effects on dynamic growth of voids in ductile materials. Theoretical analysis indicates that the inertial effect (kinetic energy of void growth) mainly dominates the behavior of the void growth in temperature-dependent and high-strain-rate cases. Otherwise, the viscoplastic effect dominates and the inertial effect can be neglected. The rate of the dynamic growth of voids increases when the thermal effect is considered. An expression of the threshold stress for the void growth is obtained, which depends on the initial porosity, the porosity, the yield strength, the density of surface energy of voids, the initial temperature, and the melting temperature.