More on the secondary penetration of long rods

The secondary penetration of long rods, impacting semi-infinite metallic targets, has been investigated since the early 60ʹs, both experimentally and analytically. Several models have been proposed for the extra penetration which is achieved by these rods at the later stages of the process. However, the models are of limited applicability since they cover only limited regimes of the relevant parameters. In order to further understand the phenomenon of secondary penetration, we performed a large number of numerical simulations using the PISCES 2 DELK code. These simulations dealt with the relevant parameters in large ranges of variability, such as: the rod impact velocity, its aspect ratio (L/D), as well as the densities and strengths of rod and target material. We show that the semi-empirical formulations do not account for the whole range of these parameters. Our simulations show that the strength of the rod has a major influence on the values of the secondary penetrations. In addition, these values are strongly dependent on L/D and target strength.