Penetration Performance of the Train of Solid and Hollow Disks

The penetration performance of homogeneous disk (μ = 0) and thick walled disk (μ < 0.5) projectiles are investigated numerically for length-to-diameter ratio (L/D) of 1/8 and 1/4, where μ is the ratio of inner to outer diameter of a disk. Penetrations of tungsten alloy projectiles up to 4 successive solid disks (SD) and hollow disks (HD) with spacing of 1.5, 2 and 3 diameters into rolled homogeneous armor (RHA) at 2.6 km/s were simulated with a finite difference nonlinear wave propagation program. The most obvious results from the calculations are that even at 2.6 km/s the total penetration of a 4-segmented projectile can not be obtained simply be multiplying the depth of a single disk by four, especially for L/D = 1/8. Although HD may be more efficient, in terms of mass, than SD of equal outer diameter, it is observed that precursor or jet interacts with a train of spaced HD. This interaction significantly reduces the penetration performance, which was also measured in the long tubular projectiles. The degradation in total penetration becomes worse as μ increases. For HD of L/D = 1/4 case, the degradation in penetration becomes less since the effect of the interaction of jet with successive disks is relatively small.