Effect of polyurea layer on ballistic behavior of ceramic/metal armor

Polyurea is widely used as a protective material for its excellent protective performance during extreme loading. However, the ballistic behavior of polyurea-reinforced ceramic/metal armor with different positions and thicknesses under various velocity projectile impact still needs to be explored. In the present study, five groups of polyurea-reinforced ceramic/metal armor and two groups of bi-layer ceramic/metal armor were designed. The ballistic experiment was also conducted to systematically investigate the influence of position and thickness of the polyurea layer on the ballistic performance of ceramic/metal armor. The perforation processes was recorded using a high-speed camera. According to the experimental ballistic data, parameters of the Recht-Ipson (R-I) model were obtained, and the fractographic analysis of the target was conducted. It was found that the polyurea layer of 1.1 mm thickness on the front face could effectively increases the ballistic limit velocity by 27.99 m/s and the specific energy absorption by 8.83 %. However, this effect depends on the thickness and position of the polyurea layer. Moreover, a three-dimensional finite element model was performed to explore the protective mechanism of the polyurea layer. The enhancement mechanism of the polyurea layer consists of three aspects: (1). the polyurea layer increases the angle of the ceramic cone; (2). the polyurea layer increases the confining pressure of the ceramic; (3) polyurea has a strengthening effect at a high strain rate. The results of this study facilitate the further understanding of ballistic performance of the polyurea-reinforced ceramic/metal armor.