Behind the armor debris distribution function

The fragmentation of the bulge, which is formed during the perforation process of an RHA plate, together with the eroded projectile material constitute "behind the armor debris". It was assumed that the fragments which emerge from the target are uniformly distributed on an ellipsoid surface, while the projectile fragment mass is uniformly spread within the ellipsoid volume. A simple model was developed to describe the dispersion of these fragments. It is assumed that this cloud has a shape of a truncated ellipsoid. The fastest fragment moves with a velocity equal to the residual projectile velocity, and the rear, and slower, part of the ellipsoid moves with a velocity which depends on target material properties. Employing this model, expressions for the debris distributions, such as accumulated mass and mass per unit angle or per unit area, vs. angle, were derived. Examination of the available experimental results shows good correlation with the model predictions.