Attenuation of underwater explosion propagating through porous compressible foam

Collision of underwater explosion and a rigid plate or high porosity foam is investigated experimentally and numerically. As the motivation of this study, it is deduced that attenuation behavior of strong shock environment by porous compressible foam depends on the porosity, cell structure and acoustic impedance in the foam. All foam has open cell type cellular structure, high porosity, low density and low acoustic impedance in comparison with metal and plastic. Experiment on underwater explosion-foam interaction is conducted by using the micro-explosive. Variation of total stress in foam does not show underwater shock pressure-time history and pulsating of the gas bubble. Peak stress of incident shock impingement and bubble pulse in foam with cell number 50 are decreasing up to 99 % and 95 to 98 % of the dynamic pressure value in aluminum plate case. Result of numerical simulation is compared with the experimental findings, which shows essentially same gas bubble motion with experimental result.