Flow localization behavior of elasto-viscoplastic plane-strain blocks under high strain rate

The thermocoupled flow localization of plane-strain compression blocks under high strain rate has been investigated. A phenomenological thermo-elasto-viscoplastic constitutive law accounting for the strain rate history dependence is developed to describe the material behavior under high strain rate with and without abrupt strain rate change. An inertial force is also considered in dealing with the deformation behavior at dynamic loading through the principle of virtual work. Results of the finite element analysis based on the proposed constitutive model show that the effect of inertial force causes the wiggles of the nominal stress versus nominal strain and significant retardation of shear band development. Flow localization starts at central part of a block and manifests itself as the viscoplastic strain development emanating from the inhomogeneity. With an abrupt change of the strain rate, the positive/negative strain rate history dependence causes shear band development to retard/accelerate.