NUMERICAL STUDY OF DUCTILE VOID GROWTH UNDER DYNAMIC LOADING CONDITIONS

A numerical study of void growth at differing global strain rates in t he range 149 s(-1)- 2240s(-1) and at start temperatures between 173K a nd 573K has been carried out fbr a material containing a threedimensio nal periodic array of equally spaced, initially spherical voids. To ta ke account of the effect of strain rate and temperature on the flow st ress under dynamic adiabatic conditions, the well-established Zerilli- Armstrong constitutive relations for pure copper and iron have been em ployed. An instability criterion based on the maximum mean tensile str ess has been used to identify the point at which unstable void growth occurs. For both materials, the strain at instability has been found t o be dependent on stress triaxiality ant start temperature but only we akly affected by strain-rate.