Experiments have been conducted to examine the influence of an adjacent crater or craters onthe perforation performance of a diameter D=20mm fragment simulating projectile (FSP).Five FSPs were fired sequentially at impact velocities of approximately 1000m/s into a 15mmthick mild steel plate. An increase in residual velocity of 13% compared to a single impactwas observed when two sequential impacts were 29mm (1.4D) apart. An impact next to twocraters with the same 1.4D spacing increased the residual velocity (compared to a singleimpact) by 57%. An energy balance equation was used as the basis for a generalised model. Itwas found that the influence of the adjacent crater could be predicted from a calculation of thereduction in sheared circumference and the reduction in target plug mass. From the model itwas found that the minimum spacing to avoid the influence of an adjacent crater was 1.55D at1300m/s. The model was extended to include the effect of more than one adjacent crater, andgave reasonably good agreement with the experimental results.
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