Steady-state smear band propagation under dynamic conditions

The dynamic propagation of a shear band is assessed in mode II. A layer of finite thickness is subjected to simple shearing.:The band propagates in the shear direction under steady state conditions. Three parameters are used to characterize the process: the shear band velocity, the length of the process zone and the width of the sheer band. The process zone is the region at the vicinity of the shear band tip where the strain rate changes rapidly from a quasi-uniform profile to a localized distribution. The shear band velocity and the length of the process zone are calculated by use of a variational approach. We analyse the roles of inertia, of loading conditions and of material properties such as yield stress, strain (or thermal) softening, strain hardening, strain rate sensitivity. The effect of elastic energy release is shown to be important in general. Comparisons with experimental results are made. (C) 1998 Elsevier Science Ltd. All rights reserved.