Experimental investigation on the ballistic performance of monolithic and layered metal plates subjected to impact by blunt rigid projectiles

In this paper, a series of impact tests were conducted to investigate the ballistic performance of monolithic and multi-layered metal plates subjected to impact by blunt rigid projectiles. Layered plates arranged in various combinations of equivalent total thickness were normally impacted at different velocities by a gas gun. Ballistic limit velocity for each configuration target was obtained based on the investigation of the effect of the air gap between layers, the number, order and thickness of layers on the ballistic resistance. The results showed that the monolithic targets were more effective than layered targets when the dominant response of monolithic targets was dishing which involved membrane stretching, and the ballistic limit velocities of layered plates decreased with the increase of the number of layers. Conversely, the monolithic targets had lower ballistic limit velocities than layered targets if total thickness above a specific value that the dominant response of monolithic targets was shearing. Moreover, the air gap significantly affected the ballistic resistance of spaced layered plates. Layered targets with larger air gap were stronger than those with small air gap, and also there were two ballistic limit velocities in the former configuration. On the other hand, as the order of layers affected the ballistic resistance of double-layered targets, the ballistic resistance was better when the first layer was thicker than the second layer.

► Air gap between layers affects the ballistic resistance of layered plates.
► The different layering effect results from the transitions of failure models.
► The change in thickness leads to the transitions of main failure models.
► The layering order affects the ballistic resistance of layered plates.
► The number of layers affects the ballistic resistance of layered plates.