Theoretical and experimental study of shaped charge jet penetration into high and Ultra-high strength concrete targets

The depth of penetration (DOP) for concrete targets generated by a jet is required to achieve a certain value, under the premise of which the crater diameter must be sufficiently large in the present design of a shaped charge. A large cavity generated by the precursor shaped charge of a tandem warhead is conducive to the penetration of the follow-through projectile. Given the rapidly developing and increasingly extensive application of high and ultra-high strength concrete (H&UHSC), which has excellent resistance to penetration, impact and blasting, shaped charge jet penetration into the targets was investigated in this study. The chase between the incoming elastic wave, plastic wave and the jet/target interface as the shaped charge jet moves into H&UHSC targets were discussed. The response regions in the target were analyzed. Four penetration stages were proposed, while the corresponding modified Bernoulli equations were established. The two-stage mechanism of cavity growth was used to describe the penetration modes. Furthermore, the DOP experiments for two different structures of shaped charge penetration into H&UHSC targets with four strength grades were conducted. The predictions of depths and hole profiles from the present model correlate with the experimental data reasonably well. Results indicate that the DOP decreases exponentially as the compressive strength of H&UHSC increases at the beginning, and then the rate of the decreasing tendency slows down gradually and approximates the limit when the compressive strength approaches 200 MPa. Moreover, the cavity diameters resulted from the jet into the H&UHSC targets exhibit insensitivity to the increasing strength grade. The jet with diverse velocity and diameter structure may experience different penetration stages as it penetrates various H&UHSC targets, which affects the penetration result.