Ballistic performance of monolithic and double layered thin-metallic hemispherical shells at normal and oblique impact

Abstract

The present study discusses experimental and numerical investigations on the ballistic performance of aluminum 1100-H12 hemispherical shell targets of 150 mm diameter against 19 mm diameter cylindrical steel projectiles. The influence of nose profile of the projectiles on the impact resistance of the targets, was observed by varying the nose geometry to ogive, blunt, conical and hemispherical shapes. Effect of normal as well as oblique impact on the failure mechanisms and perforation process of shells was studied at 0 (normal), 15 and 30° angle from the normal incidence path. Further, the ballistic performance of two target configurations, viz. 2 mm thick monolithic and double layered in-contact shell targets was investigated and compared within the configurations. The finite element analysis of the ballistic impact on shell targets was done in ABAQUS/Explicit solver by employing the Johnson – Cook constitutive strength and damage model for deformable target material, whereas all the projectiles were assumed as rigid body. The ballistic performance of both shell target configurations against oblique impacts with different projectiles was evaluated and compared in terms of ballistic limit, local and global deformations, failure mechanisms and plastic work done in radial, polar, meridional and shear deformations. The obtained experimental results were then compared with numerical simulations and found in good corroboration. It was observed that both monolithic and layered shell targets showed highest ballistic resistance against hemispherical nosed projectile. For all the projectiles, layered shell targets displayed higher energy dissipation than monolithic targets.