Degradation mechanisms in shaped charge jet penetration

The mechanisms governing the penetration of shaped charge jets over the full range of stand-offs remain only partially understood. This paper explores various potential degradation mechanisms with the aim of identifying those that are most significant to the penetration process. The mechanisms addressed are: particle shape effects, particle separation, the extent of necking, the deposition of jet material and the effects of collisions of the particles with the crater wall. The study consists primarily of hydrocode simulations using the DERA Eulerian code cAst-Euler. In each case the effects of one or more copper particles impacting upon a semi-infinite Rolled Homogeneous Armour target are modelled. It is concluded from the study that particle shape and impact speed can be significant factors contributing to penetration degradation. Collisions at the side of the crater and tumbling of the particles are also likely to be adverse factors.