Breaking behavior and stress distribution of T12A hard steel core penetrating ceramic/aluminum alloy lightweight composite armor

Abstract

The armor-piercing incendiary (API) round inflicts significant damage to light armor. This article conducts penetration experiments on lightweight ceramic composite armor using 12.7 mm API rounds. The Rosin-Rammer distribution model is used to analyze the macroscopic fragmentation characteristics of the core, and the SEM is used to analyze the fracture surface of the bullet core after fragmentation at the microscopic level. Numerical simulations are also used to verify and expand the material parameters. The experimental results show that as the penetration velocity increases, the average feature size of the core decreases, indicating an increase in the degree of fragmentation of the core. The fragments generated by the fragmentation can be almost completely restored. The main fracture form is the brittle crushing fracture of the head of the projectile, while the tail and body of the projectile are basically intact, and the fracture surface is mainly a 45° shear fracture and radial platform-like tensile fracture.At the microscopic level, SEM images show that the material fracture mainly occurs in the form of radial cleavage shear fracture and river patterned tensile-shear fracture. The numerical simulation results show that as the penetration velocity increases, the energy dissipation of the core continuously increases. The main energy dissipation process of the core during penetration occurs during the contact with the ceramic cone, accounting for 66.48 % of the total energy loss, while the mass of the core remains almost unchanged during the interaction with the aluminum alloy.In addition, the experiment is verifiedusing different working conditions at different angles, confirming that the "unequal tearing" of the aluminum alloy backing plate is caused by the inclination of the penetration angle. It was also found that the penetration efficiency and destructive capability of the API round are significantly reduced when there is an angled penetration.