EFFECT OF THERMAL-CONDUCTIVITY ON THE INITIATION, GROWTH AND BANDWIDTH OF ADIABATIC SHEAR BANDS

We ascertain the effect of thermal conductivity on the initiation and growth of shear bands in a structural steel by analyzing the development of shear bands in a block undergoing overall adiabatic simple shearing deformations. The material of the block is assumed to exhibit strain and strain-rate hardening, and thermal softening. Three constitutive relations, namely, the Litonski law, the Bodner-Partom law, and the Johnson-Cook law, have been used to model the thermoviscoplastic response of the material. For each material model, five values of thermal conductivity differing by three orders of magnitude have been used. It is found that an increase in the value of the thermal conductivity delays the initiation and slows down the subsequent development of the shear band. For the Litonski law and Johnson-Cook law, the band width tends to zero as the thermal conductivity approaches zero. However, for the Bodner-Partom law, the band width is non-zero even when the thermal conductivity is set equal to zero.