CAVITATION INSTABILITIES IN ELASTIC PLASTIC SOLIDS

A CAVITATION instability occurs when an isolated void in an infinite, remotely stressed elastic-plastic solid grows without bound under no change of remote stress or strain. The cavitation instability can be thought of as a process in which elastic energy stored in the remote field drives the plastic expansion of the void. The paper begins with a brief review of cavitation under spherically symmetric stress states and then goes on to consider the problem for cavitation states under general axisymmetric stressing. It is found that the criterion for cavitation under multiaxial axisymmetric stressing depends on the attainment of a critical value of the mean stress, to a reasonably good approximation. A set of recent experiments is discussed in which cavitation instabilities appear to have occurred. The last section of the paper reviews available theoretical results for the dilatation rates of isolated voids. The most commonly used formulae underestimate the dilation rate under stress states with modern to high triaxiality.