Steady-state penetration of viscoplastic targets

Abstract

The problem of steady-state penetration by a semi-infinite, rigid cylindrical penetrator with an ellipsoidal nose into an infinite, rigid-viscoplastic target has been studied. The target material is assumed to obey a generalized form of Von Mises yield criterion to account for the strain-rate dependence. Contact between target and penetrator is assumed to be smooth. Computed results show that the deformation field adjacent to the nose of the penetrator is significantly different in the ellipsoidal case from what it is when the nose is hemispherical. Results presented graphically include the dependence of the axial resisting force on penetrator speed, the ratio of the major to minor axes of its ellipsoidal nose, and the strain-rate hardening parameter of the target. Also depicted are the normal pressure over the penetrator nose and the velocity field in different parts of the target.