Effect of Flyer Plate Velocity and Rate of Crater Expansion on Performance of Explosive Reactive Armour

Abstract

reduction in the penetration power of the jet due to its interaction with an obliquely moving plate of explosive reactive armour (ERA) sandwich has been studied. It has been assumed that the length of the jet, which gets disturbed due to its interaction with the edge of the hole made by the impact of the tip of the jet when the plate was stationary, does not contribute to penetration in the target. The jet length, which comes out of the hole undisturbed, penetrates the target. This length of the jet has been calculated considering the variation in plate velocity and rate of expansion of the crater in the plate with time. The time taken by the jet to shift its position from the centre to the wall of the hole has been determined for different velocities of the sandwich plate and varying expansion rates of the hole produced by the jet in the plate, corresponding to a constant velocity of the jet. This analysis has been used to obtain the length of undisturbed jet coming out of the hole and its penetration in the target. The present study establishes the effect of the plate velocity and rate of crater expansion on the performance of the ERA. It has been found that both these parameters affect the performance of the ERA, and the metal plates of lower density and higher strength make the ERA more effective.