TOWARDS A UNIFIED DISLOCATION-BASED MODEL FOR SHAPED CHARGE JET BREAK-UP

An old model for the ductility of shaped charge jets from metallic liners based on the behaviour of moving dislocations is reviewed in the light of new knowledge of dislocation dynamics in metals when subjected to high strain rates and large strains. A phenomenological description of jet ductility is given based on postulates regarding the generation and motion of dislocations during the shaped charge jet collapse process, as well as the depletion of the mobile dislocation population during the stretching phase of the jet. The model explicitly includes the effect of grain size in the liner on the ductility of the jet. Most of the features of jet break-up can be deduced and realistic jet break-up times are predicted for homologous designs.