Protection performance of double-layered metal shields against projectile impact

Abstract

This paper critically evaluates the protection performance of double-layered shields against projectile impact at the subordnance velocity using finite element methods. Four types of projectiles of different weight and nose shape are considered, representing various fragments generated from Improvised Explosive Devices (IEDs). It is found that the double-layer configuration is able to improve the ballistic resistance by 8.0%-25.0% for the flat-nose projectile, compared to the monolithic plate of the same weight. The upgrade is due to the transition of the failure mode from less energy dissipating shear plugging to more energy dissipating tensile tearing. Under impact by the conical-nose projectile, the double-layered target is almost as capable as the monolithic plate. The present research helps resolve the long outstanding issue of the protection effectiveness of the double-layer configuration.