NUMERICAL EXPERIMENTS ON ADIABATIC SHEAR BAND FORMATION IN ONE DIMENSION

Adiabatic shear band formation in an elastic, thermoviscoplastic, simple material is studied in the context of unidirectional shearing of a slab. The effect of varying the thermal softening behavior of the material on localization strain and postlocalization morphology is studied for a rigid, perfectly plastic material; the material parameters are appropriate for a high-strength steel. In this case it is demonstrated that localization of the strain rate can be transient. A coupling between linear-elastic response and the basic thermoviscoplastic localization mechanism is explored in the absence of strain hardening. Last, the flow law is modified to include strain hardening in order to simulate a high-rate torsion test on OFHC copper. In this case localization is initiated by thermal boundary layer diffusion and the solution takes on a complex, apparently nonperiodic, postlocalization morphology quite different from that in the perfectly plastic cases.