Ballistic limit velocity of empty rectangular metal columns under a blunt projectile penetration

Abstract

This paper studies the ballistic limit velocity of empty rectangular columns under a blunt projectile penetration, theoretically and numerically. The deformation mechanism of the empty column is considered as plugging. The projectile is assumed to be a flat-ended cylinder without deformation. A new theoretical model of deformation is introduced, and based on the energy method, a theoretical formula is derived to estimate the ballistic limit velocity of the process. Numerical simulations of the penetration process of a blunt solid cylinder into the empty metal columns are performed using the LS-DYNA explicit solver. Different empty columns are used as the targets, and these columns are made from Weldox 460E steel and have different wall thicknesses (6, 7, 8 and 9 mm) and internal column edge lengths (60, 70, 80 and 90 mm). To validate the derived relation for the ballistic limit velocity, the results of the numerical simulations are compared with the corresponding theoretical predictions. Finally, the effects of some geometrical characteristics such as projectile diameter and mass on the perforation process and the ballistic limit velocity are discussed.