The ballistic resistance of multi-layered targets impacted by rigid projectiles

This paper studies the resistance characteristics of double-layered targets by using two different materials including steel and aluminum. Four types of double-layered targets are considered: aluminum-aluminum, aluminum-steel, steel-aluminum and steel-steel. Using these four targets, penetration tests are carried out on 1 mm-thick plates with blunt nosed projectiles. A compressed gas gun was used to launch projectile within the velocity range from 50 to 400 m/s. Standard steel projectile for perforation of steel and aluminum plates has been used when the aspect ratio, that is L/D, of the projectile is 8 and projectile is cylindrical flat-ended. The initial and residual velocities of the projectile were measured, and reported. Also, numerical simulations of some of the experimental tests are carried out using the non-linear finite element code LS-DYNA. A slightly modified version of the Johnson-Cook constitutive equation and fracture criterion was used to simulate material behavior. The predictions of the Ipson and Recht analytical model are compared with the obtained results. The correlation between the analytical, the numerical and the available experimental results demonstrates that the numerical method is a very accurate and effective analysis technique in perforation of multi-layered metallic targets. (C) 2011 Elsevier B.V. All rights reserved.