EFFECT OF INITIAL VOID SHAPE ON THE OCCURRENCE OF CAVITATION INSTABILITIES IN ELASTIC-PLASTIC SOLIDS

A void in nn infinite elastic-plastic material grows without bound when a cavitation stress limit is reached. Such unstable void expansion, driven by the elastic energy stored in the surrounding material, has been studied for the relatively simple case of spherically symmetric conditions and also for a spherical void in an axisymmetric remote stress field. The analyses are here extended to consider the effect of a void with an initially prolate or oblate spheroidal shape. Numerical unit cell analyses are carried out for a power-hardening elastic-plastic material subject to various axisymmetric remote stress states. For the range of void shapes analyzed it is found that the critical cavitation stress state shows very little influence of the initial void shape.