Low velocity perforation of mild steel circular plates with projectiles having different shaped impact faces

This article studies the perforation of mild steel circular plates struck normally by cylindrical projectiles having blunt, hemispherical, and conical impact faces. Experimental results are obtained using a drop hammer rig for the perforation of 2-8 mm thick plates struck by projectiles weighing between 1.75 kg and 176 kg and traveling up to about 12 m/s. The impact positions are at several radial locations across a plate, and it turns out that the perforation energy decreases as the impact location is moved away from a plate center toward the support. It transpires that the projectiles with hemispherical and blunt impact faces require the largest and the smallest impact perforation energies, respectively. Comparisons are made between the experimental results for the perforation energies and the predictions of several empirical equations. Design calculations for the impact perforation of plates could be undertaken using projectiles with blunt impact faces, which would provide a lower bound on the perforation energy of projectiles having hemispherical or conical impact faces, at least within the range of the parameters studied.