Effects of casing on underwater explosion of aluminized explosive

Underwater explosion experiments were carried out on cylindrical aluminized explosives. The charges surrounded by 6 mm thick steel casing, AL casing and PVC casing, as well as two bare charges were fired. The shock wave pressure-time curves were measured respectively at the distance of 3 m, 5 m and 7 m. The peak pressure, impulse and energy of shock wave and the bubble energy were also worked out. Numerical simulations using AUTODYN-2D support the experimental results. According to the dimensional analysis and numerical simulation, the variations of shock wave profile, peak pressure and bubble period along with the change of relative charge mass were studied. The results show that the peak pressure and energy of the shock wave will be all enhanced when the relative charge mass is small, but will decrease when the relative charge mass is too large. The bubble period of the casing charge is lower than that of the bare charge. The optimal relative charge mass is 1.45 for the steel casing charge. The finite element model and calculation results can provide a reference for the design of underwater weapons.