On the effects of growth and stabilization of dynamic spall strength under short-pulse actions

The effects of growth and stabilization of dynamic spall strength under short-pulse actions are studied. By substituting the sum of the incident stress pulse and the stress pulse reflected from the free surface, dependence of the dynamic strength on the strain rate is obtained. It is noted that the destroying amplitude depends only on the strain rate and that for short pulses, the condition of fracture arises simultaneously at two sites of the material. It is also shown that after reaching some strain rate, the spall strength reaches a value of 8 GPa and that the strength remains unchanged with increasing strain rate. The specified strain rate determines the angle of inclination of the triangle at the stage of an increase of the local tensile stress. It is also found that the strength at a given strain rate depending on other parameters of action can be changed in rather wide limits.