Influence of Drift Velocity and Distance Between Jet Particles on the Penetration Depth of Shaped Charges

摘要

The penetration depth of shaped charge jet into target is strongly affected by the stand-off. The penetration process terminates even when the jet velocity is still high, and the penetration capability of jet particles degrades after jet breakup at a large stand-off. This work presents an analytical model to describe the radial drift velocity and distance between jet particles, which leads to decreased penetration depth. The results show that jet particles with low drift velocity impact the crater wall easily. Furthermore, the jet particles cannot reach the crater bottom to increase depth because the crater diameter generated by the jet is quite small. Moreover, the distances between jet particles also play an important role in penetration depth under the influences of strain hardening of target, as well as tumbling and dispersion of jet particles. The radial drift velocity and distance between jet particles are investigated by applying the model to non-precision charge and precision charge penetrations into target at different stand-offs. The cutoff jet velocity and cutoff penetration velocity also are determined based on the analytical model. With increased stand-off, the cutoff jet velocity increases, and the cutoff penetration velocity is almost constant. This result is proven by a number of experiments. The stand-off curves of two charges are also calculated, and results are in good agreement with experiments. The stand-off curve can be determined with only two or three experiments using the proposed method. Notably, jet particles should have a slow drift velocity and great penetration capability after breakup for suitable shaped charge.