On ballistic performance of a metal target with crescent-shaped cavity structure

Abstract

To improve the ballistic performance of metal targets, a metallic structure composed of a series of crescent-shaped cavity cells, whose spatial distribution is similar to a honeycomb, was proposed. Each cavity cell is formed by two balls with an identical diameter offset by a certain distance and its shape looks like a crescent moon. The deflection performance of crescent-shaped cavity structures impacted by 12.7 mm armor-piercing incendiary projectile cores at an initial velocity of 818 m/s was studied numerically. Based on 3D voxel models, numerical simulation was carried out by using the finite element code ABAQUS/Explicit. The deflection angle of the projectile related to the initial impact direction was measured in the process of penetration simulation. By comparing with the experimental results in the literature, a virtual test was carried out to verify the validity of the finite element model. The influences of crescent shape, hitting position and space arrangement of cavity cells on the deflection performance were analyzed. The results show that the crescent shape has a significant effect on the overall deflection performance of the target. The deflection angle of the projectile increases with the increase of the cavity diameter, but the protection performance of the structure with larger cavity diameter becomes weaker. A cavity diameter of 18 mm with the offset distance of 5.4 mm may be appropriate when considering a high deflection performance without significant drop of the protection performance of the target plate. The target impacted by the projectile at different hitting positions shows different deflection performances. The deflection angle of the projectile is much large at those positions where the material distribution has a high asymmetry. The asymmetric treatment of the space arrangement of cavity cells can improve the deflection effect of the cavity structure. The deflection mechanism of the cavity structure is that when the projectile penetrates the interface between the material and cavity inside the target plate, the projectile is subjected to an asymmetric force distribution, which affects the subsequent penetration process.