FINITE-ELEMENT ANALYSIS OF THERMOMECHANICAL COUPLING IN TENSILE INSTABILITY

A numerical routine is developed to investigate the necking behaviour of a round tensile specimen with strain-hardening, strain-rate sensitive and thermal softening characteristics. The destabilizing influence of thermal softening on localization process is investigated at different nominal strain-rate levels, for which the inertia can be neglected and the effect of heat flux on the transient heating process is important enough to render the process non-adiabatic. The incremental form of the governing equations for the displacement and temperature fields are decoupled, solved and updated for respective field quantities successively, to produce the overall thermomechanical response. Comparisons with temperature-independent counterparts are presented.