Experimental studies on the effect of size and shape of holes on damage and microstructure of high hardness armour steel plates under ballistic impact

In the present work the effect of size and shape of regularly spaced holes on the ballistic impact behavior of high hardness steel plates has been studied. Thick backing technique was used to evaluate the efficiency of these plates when subjected to ballistic impact of 7.62 mm non-deformable hard steel core projectiles. The ballistic efficiency of these steel plates was found to be sensitive to size of the holes. Higher efficiency was found for plates with hole sizes close to the diameter of the projectile. Damage patterns and microstructure of the perforated steel plate have been compared with those of non-perforated steel plates. It has been found that presence of holes inhibits shear band formation in the target plates.