Ballistic protection and damage mechanism of ceramic composite armor under two-dimensional pre-stressed constraints by molten metal casting

To meet the requirements for lightweight and high-performance protection in ceramic composite armor, two-dimensional prestressing of brittle ceramics is achieved based on the principle of molten metal cooling shrinkage. The protective performance of two-dimensional prestressed (2DP) and non-prestressed (2DN) ceramic composite armors is evaluated through ballistic impact tests. High-speed cameras and 3D digital image correlation (3D-DIC) techniques are employed to dynamically capture the penetration and damage processes of the ceramic composite armor targets. The Rosin-Rammler distribution model is used to analyze and compare the fragmentation degrees of ceramic targets after penetration. Additionally, full process coupled simulation, encompassing the preparation and the ballistic impact of ceramic composite target, is achieved through the finite element software ProCast and Ls-Dyna. Based on the depth of penetration (DOP) test, the residual depth of witness after penetration is measured, and the protection coefficients of two type of target at different velocities are quantitatively obtained. The experimental and simulation results indicate that, 2DP ceramic composite armor demonstrates better ballistic protection capability compared to 2DN ceramic composite armor. The presence of prestress prolongs the dwell time of the projectile on the projectile-facing surface, which hinders the forward movement of the projectile, resulting in significant velocity attenuation and radial deformation of projectile's nose. Additionally, the fragment size of 2DP ceramic composite armor is smaller, and the ceramic fragmentation energy absorption continuously dissipates the kinetic energy of projectile. Within a velocity range of 600 m/s∼1400 m/s, the protection coefficient of 2DP is 8.11 % to 48.64 % higher than that of 2DN.