STEADY-STATE AXISYMMETRICAL PENETRATION OF A KINEMATICALLY HARDENING THERMOVISCOPLASTIC TARGET

We study axisymmetric thermomechanical deformations of a thick target being penetrated by a fast-moving rigid cylindrical rod with a hemisph erical nose, and presume that target deformations appear steady to an observer situated at the penetrator nose tip. Both isotropic and kinem atic hardening of the target material are considered. It is found that kinematic hardening increases the normal stress acting on the penetra tor nose surface and the temperature rise of target particles abutting the penetrator. However, the value of the hydrostatic pressure at a p oint in the deforming target region is affected very little by the con sideration of kinematic hardening. For suitable values of material par ameters appearing in the evolution equation of the back-stress, the co mputed values of the back-stress at target particles abutting the pene trator nose surface equal three times the yield stress of the target m aterial in a quasistatic simple compression test.