Strain-rate-dependent cohesive zone modelling of charge damage behavior when a projectile penetrates multilayered targets

The high impulsive overload when a projectile penetrates multilayered targets affects the performance of explosive charge, which is an important component of many weapons. A tensile stress wave is generated in the charge when the compressive stress wave is reflected from the free surface, which is the main reason of the damage occurrence. Here, the damage behavior of charge under the multiple high impulsive overloads is systematically studied by a strain-rate-dependent cohesive zone model. Therein, a critical δ_n (normal separation) is determined to describe the macrodamage evolution of charge by contrasting the predictions with the experimental results. Our numerical results show that the δ_n at the edge of charge is larger than that in the interior and that the angle between the macrodamage area and the transversal direction increases with the targets obliquity. It is found that the maximum δ_n and the macrodamage proportion during oblique penetration are larger than those during normal penetration. With the increase in the projectile velocity, the maximum δ_n and the total macrodamage proportion increase, and severe macrodamage area is closer to the tail. As the targets spacing expands, both the maximum δ_n and the total macrodamage proportion change non-monotonically, while the distance from the severe macrodamage area to the tail expands.