Strain-Rate Effects in Metals

Abstract

A series of computations has been completed which investigates strain-rate effects on stress-wave propagation in metals. The principal difficulty in calculations of this type is the choice of a functional relationship between stress, strain, and strain rate. Experimental results have shown that the stress-strain relation of a material experimentally determined under quasistatic conditions may not be extended to dynamic conditions, i.e., the rate of loading is important. Therefore, a relation between stress, strain, and strain rate was constructed that is consistent with the experimental observations of plastic wave propagation in high-purity aluminum rods (one-dimensional stress) and adapted to the behavior of 6061-T6 aluminum. This function was then used to calculate the propagation characteristics of a stress pulse propagating in a state of one-dimensional strain. The calculations compare favorably with the experimentally observed dynamic behavior of 6061-T6 aluminum impacted at 322 m/sec.