Inertia and Temperature Effects in Void Growth

Abstract

The usual solution for void growth in a ductile metal is based on the assumption that the velocity of growth is proportional to the current void size and inversely proportional to the material viscosity. In this study we examine the additional effects of inertia and temperature on void growth. The solution of Poritsky (1) includes the large effect of inertia on the growth rate of large voids. As the voids rapidly expand during high‐rate fracture, the material near the void surface becomes hot and its strength and viscosity may both reduce because of this heating. We performed finite‐element simulations to study the growth of a single spherical void under tensile loading in a viscous material, thereby accounting for viscous, thermal, and inertia effects. In aluminum the thermal strength reduction effect allows small voids to expand about 35% more rapidly than without the effect. We propose a simple approximate method for treating the viscous, thermal, and inertia effects in void growth.