Penetration of annular and general jets into underwater plates

Underwater structures can be seriously damaged by a metal jet associated with underwater explosion. Three main modes—Shaped Charge Jet, Jetting Projectile Charge and Explosive Formed Projectile—are included for traditional metal jets. Compared with the traditional ones, an annular jet may cause more serious damage into a target. Hence, a comparison for the entire process of annular and general jets penetration into underwater plates was analysed in this paper. Since Smoothed Particle Hydrodynamics (SPH) method has advantages of solving problems of large deformations, a modified scheme for approximating kernel gradient is used in simulation of processes of shaped charge detonation, jet formation and its penetration into underwater plates. An SPH model of an annular jet penetration into a steel target was first developed, and its numerical results were compared with experimental data. Then, models of annular and general jets associated with underwater explosion penetrating a plate were built. After that, the wave propagation in the detonation process and the formation of annular and general jets were analysed. Finally, damage characteristics of plates subjected to these two metal jets were compared.