Numerical Investigation of the Effect of Layering Thickness on the Ballistic Response of Ceramic/Metal Composite Structure

Three-dimensional numerical simulations were carried out using ANSYS-LSDYNA((R)) to know the ballistic performance of the ceramic/metal composite armour structure when subjected to normal impact of 7.62 and 12.7 mm API projectiles. Two distinct ceramic, boron carbide (B4C) and alumina (Al2O3) having backing plates of 6061-T6 aluminum were considered as target materials. Keeping total equivalent thickness constant, 15 mm, the thickness of ceramic and the backing plate was varied in combination of 3-12, 6-9, 7.5-7.5, 9-6, and 12-3 mm. The velocity of both the projectiles was varied in between 600-800 m/s. The obtained numerical results were first validated with the available experimental results and subsequently the ballistic resistance of ceramic/metal targets were compared with the ballistic resistance of Armox-500T steel against identical projectiles. The ballistic performance of the above targets was explored with the residual kinetic energy of the projectile, projectile erosion and kinetic energy absorbed by the target. The kinetic energy absorbed by the target was shown to dissipate into the fragments that leave the ceramic and in plastic deformation. Two different methodologies, smoothed particle hydrodynamics (SPH) and finite element analysis (FEA) were considered to carry out the numerical simulation to know their ability to predict the ballistic phenomenon. It was found that SPH simulation can properly predict the impact between target and projectile and showed good prediction accuracy. The highest resistance was obtained for boron carbide having 7.5 mm thickness closely followed by 9 mm boron carbide thickness. Target configuration with alumina showed inferior performance as compared to boron carbide target. The results showed that the thickness of front ceramic plate had a significant effect on the projectile erosion. Maximum projectile erosion of 30.6% and 10% were observed for 7.62 and 12.7 mm API, respectively, at velocity of 800 m/s impact velocity.