Influence of projectile shape on dynamic behavior of steel sheet subjected to impact and perforation

The paper describes a work focused on the process of perforation of steel sheet. Experimental, analytical and numerical investigations have been carried out to analyze in details the perforation process. Based on these approaches, the ballistic properties of the material and the failure modes depending on the projectile nose shape (conical, blunt or hemispherical) have been studied. Different failure modes have been observed, including petaling, plug ejection and circumference necking. The special study about the number of petals has been done for different nose angles using conical shape projectiles. The complete energy balance is also reported and the absorbed energy by the steel sheet has been obtained by measuring initial and residual projectile velocities. A wide range of impact velocities from 35 to 180 m/s has been covered during the tests. All the projectiles are 13 mm in diameter and the plates are 1 mm thick. Moreover, the mass ratio (projectile mass/steel sheet mass) and the ratio between the span of the steel sheet and the diameter of the projectile are constant, equal to 0.38 and 3.85, respectively.