Study of Shield Design for Shock Mitigation

Detonation of high explosive due to impact of fragments and flyer plates was modeled using hydrodynamic computer code. Included in the model were the warhead consisting of casing and high explosive (which is H-6 in this case). An 80-gram fragment simulated projectile (FSP) was used as the projectile. Flyer plates considered are single- and multi-layer structures. A reactive flow model which is able to capture the initiation, propagation and complete detonation or deflagration of detonation was used to predict the occurrence of complete detonation. Analyses were performed with several impact velocities to obtain the velocity beyond which complete detonation would occur. Shields have been used to mitigate mechanical shocks. It has been well established that shields with multi-layered materials with impedance mismatch would reduce shock levels significantly. A numerical study was conducted to derive an optimum shield design with this concept. The model used encompasses a warhead-canister system. It was assumed that one of the two adjacent warheads would detonate. The canister wall was made of multi-layered materials consisting of layers of materials made of metal and lucite. This material combination represents a medium degree of mismatch while still exhibiting certain amount of strength. The model determines the pressure level at explosive in the neighboring warhead. The pressure level was used to determine if detonation would occur, and provided a measure of effectiveness on the shields for shock mitigation.