LOCALIZATION OF DEFORMATION AND DAMAGE UNDER ADIABATIC-COMPRESSION

For dynamic compressive tests, the conditions of friction between the contact surfaces of the specimens and the bars are found to cause mech anical instability of materials with low strain hardening and low stra in rate sensitivity. The adiabatic flow curves are described by a mode l using a weakening parameter taken into account both damage and therm ally induced instability. In this paper, a material model is used, whi ch is able to describe the material behaviour in the whole range of de formation, i.e. in the region of thermally activated processes with gr adual transition to the region of damping-controlled processes.