Causes of Shaped-Charge Jet Cutoff

According to Lavrentyev's hydrodynamic theory, the penetration depth of a shaped-charge jet is determined by its total length. However, the experience of practical application of shaped charges has shown that the penetration usually ceases before the jet is completely spent. For a reliable description of experimental results, the effective length and the effective (cutoff) velocity of a shaped-charge jet are introduced to exclude from consideration the tail part of the jet that for various reasons is not involved in penetration. Effective velocity values are introduced into calculation methods as constants for a specific pair of jet and target materials or in the form of an empirical dependence on the standoff distance. The possibility of separating the jet into effective and ineffective segments based on physically justified reasons without constructing empirical dependences is considered.