ADIABATIC SHEAR BANDING IN DYNAMIC PLANE-STRAIN COMPRESSION OF A VISCOPLASTIC MATERIAL

Dynamic plane strain thermomechanical deformations of a thermally softening viscoplastic body subjected to compressive loads on the top and bottom faces are studied with the objective of exploring the effect of (a) modeling the material inhomogeneity by introducing a temperature perturbation or assuming the existence of a weak material within the block, (b) introducing two defects symmetrically placed on the vertical axis of the block. The effect of setting the thermal conductivity equal to zero is also studied in the latter case. It is found that, irrespective of the way the material inhomogeneity is modeled, a shear band initiates from the site of the defect and propagates in the direction of maximum shearing stress. The value of the average strain at the instant of the initiation of the band depends upon the strength of the material defect introduced. Once the shear band reaches the boundaries of the block it is reflected back, the angle of reflection being nearly equal to the angle of incidence. © 1990.