An extension of the umin model for cutoff of high precision jets

The mechanical processes leading to the cutoff of penetration of a shaped charge jet are still poorly understood. Eventually, high resolution 3D computer simulations may help resolve the mechanisms involved, but currently empirical models are required for practical work. The present work is concerned specifically with modeling the cutoff of high precision jets in metal targets. Motivated by a lack of success with existing jet penetration models when applied at very low drift velocities, the present work investigates a new approach. A new drift velocity term is added to one of the oldest and simplest models, the UMIN model. The new model is illustrated by applying it to the BRL 3.3 inch standard test charge, and the results are encouraging.