Constitutive modeling of high-strain-rate deformation in metals based on the evolution of an effective microstructural length

A phenomenological constitutive model is postulated to represent the response of metals over a wide range of loading conditions. The model is based on a single internal variable that can be viewed as being related to a characteristic length scale of the microstructure that develops in the metal during deformation. A scaling law for the evolution of this characteristic (or effective) length based on experimental observations is proposed. The constitutive model is illustrated by studying the response of copper and comparing with available experimental results over a very wide range of strain rates (10−2-106 s−1), strains (up to 1) and temperatures (77-473 K).