Impact resistance of concrete targets pre-damaged by explosively formed projectile (EFP) against rigid projectile

The two-stage munitions is newly utilized to attack the hard and deeply buried protective structures, while the related work on the impact performance of two-stage munitions into concrete targets is still limited. This paper addresses the impact performance of one typical two-stage munitions, which consists of a precursor explosively formed projectile (EFP) and a following rigid projectile. Firstly, based on our previous EFP impacting test on the concrete targets (Hu et al., IJIE, 2017), a series of rigid projectile penetration tests on these pre-damaged concrete targets is further conducted. By assessing the dimensions of the penetration boreholes, the influences of concrete type (normal strength concrete (NSC) and reactive powder concrete (RPC)), target configuration (monolithic and spaced) and rigid projectile striking velocity (300 m/s-500 m/s) on the targets damage subjected to the two-stage munitions are experimentally discussed. Then, by adopting the restart input data method implemented in the finite element (FE) program LS-DYNA, the targets damage subjected to the precursor EFP is recorded and the penetration process of the following rigid projectiles into the pre-damaged targets is numerically reproduced. Finally, based on the validated restart input data method, material models and the corresponding parameters, the impact performance of the two-stage munitions with different liner materials (T2 copper and 2A12 aluminum) and configurations (spherical segment, conic and truncated) of shaped charge as well as the following rigid projectile diameters (0.1∼0.9 times the shaped charge diameter) is further discussed, respectively.