Ballistic performance study on the finite steel target subjected to normal and oblique impact by copper explosively formed projectile

Subjected to normal and oblique impact by copper explosively formed projectile which is a kind of easy-deformable and soft projectile, ballistic performance of a 40-mm thickness steel target has distinct characteristics compared with the dynamic deformation of target penetrated by a rigid projectile. The failure modes of steel targets change from perforation to embedment or ricochet as the angle of obliquity increases. Correspondingly, microstructure evolution of the crater wall and morphology feature of fracture surfaces are analyzed to reveal different failure mechanisms of steel targets. The results show that the finite steel target experiences the failure mode of plug before the obliquity reaches 15° and thereafter the copper explosively formed projectile will be embedded into the crater bottom causing a big bulge on the rear surface of the steel target at low obliquities. At high angles of obliquity, the main body of copper explosively formed projectile will be ricocheted along the front surface of steel target and the critical angle of projectile ricochet is found to lie in 50° to 60° in our study. The penetration efficiency and capability of explosively formed projectile decreases as the obliquity angle increases. The results will not only help to reveal penetration mechanisms of explosively formed projectile against metallic target but also help to improve the ballistic resistance of armors