Analysis of the velocity relationship and deceleration of long-rod penetration

The relationship between the average penetration velocity, U, and the initial impact velocity, V0, in long-rod penetration has been studied recently. Experimental and simulation results all show a linear relationship between U and V0 over a wide range of V0 for different combinations of rod and target materials. However, the physical essence has not been fully revealed. In this paper, the U-V0 relationship is comprehensively analyzed using the hydrodynamic model and the Alekseevskii-Tate model. In particular, the explicit U-V0 relationships are derived from approximate solutions of the Alekseevskii-Tate model. In addition, the deceleration in long-rod penetration is discussed. The deceleration degree is quantified by a deceleration index, a 2 mu (KFJp) Yp.-1/2 p .-1/2 p +.-1/2 t V-2 0, which is mainly related to the impact velocity, rod strength, and rod/target densities. Thus, the state of the penetration process can be identified and designed in experiments.