Penetration performance and failure of long rods impacting aluminum targets

A numerical study concerning the deep penetration of long steel rods into 6061-T6511 aluminum targets at high impact velocities is presented. The range of impact velocities where these rods lose their penetration capability due to their nose deformation, or impact inclination, is explored. The numerical simulations follow several complex phenomena such as the onset of rod deformation and erosion, encountered in the tests with spherical and ogive nosed rods. It turns out that penetration depth decrease of spherical nosed rods at high impact velocities, is due to their nose deformation, while ogive nosed rods are more sensitive to impact inclination. At very high impact velocities both types of rods experience significant mass erosion, and their penetration process can be described by conventional hydrodynamic penetration model for eroding rods. The numerical simulations in this work are shown to follow test results for spherical and ogive nosed rods, impacting an aluminum alloy target at a large range of impact velocities. We show that these agreements can be achieved with relatively simple constitutive relations for the steel rods and the aluminum target.