Shear Strain Localization in Plastic Deformations

. Shear instabilities in the form of shear bands are often observed during high speed, plastic deformations of metals. According to one theory, their formation is attributed to effective strain-softening response, which results, at high strain rates, as the net outcome of the influence of thermal softening on the, normally, strain-hardening response of metals. In order to test the core instability mechanism set forth by such theories, we consider one-dimensional shear deformations of a material exhibiting strain softening and strain-rate sensitivity. The deformation is caused by either prescribed tractions or prescribed velocities. As it turns out, for moderate amounts of strain softening, strain-rate sensitivity exerts a dissipative effect and stabilizes the motion. However, once a threshold is exceeded, the response becomes unstable and shear strain localization can occur. 1. Introduction. In the framework of continuum mechanics, the motion of deforming bodies is described by system..