Tungsten long-rod penetration into confined cylinders of boron carbide at and above ordnance velocities

The purpose was to investigate the influence of impact velocity and confine ment on the resistance of boron carbide targets to the penetration of tungs ten long-rod projectiles. Experimental tests with impact velocities from 14 00 to 2600 m/s were performed using a two-stage light-gas gun and a reverse impact technique. The targets consisted of boron carbide cylinders confine d by steel tubes of various thicknesses. Simulations were carried out using the AUTODYN-2D code and Johnson-Holmquist's constitutive model with and wi thout damage evolution. The experimental results show that the penetration process had different character in three different regions. At low-impact v elocities, no significant penetration occurred, At high-impact velocities, the relation between penetration velocity and impact velocity was approxima tely linear, and the penetration was steady and symmetrical. In between, th ere was a narrow transition region of impact velocities with intermittent a nd strongly variable penetration velocity. In the lower part of this region , extended lateral flow of the projectile took place on the surface of the target. The influence of confinement on penetration velocity was found to b e small, especially at high-impact velocities, The simulated results for pe netration velocity versus impact velocity agreed fairly well with the exper imental results provided damage evolution was suspended below the transitio n region. (C) 2001 Elsevier Science Ltd. All rights reserved.