Blast response of water-backed metallic sandwich panels subject to underwater explosion - Experimental and numerical investigations

Damage severity of sandwich panels to underwater explosion load depend not only on the shock factors, but also on the fluid behind the structure. Underwater explosion tests were performed on water-backed sandwich panels to examine the deformation and failure of such composite structure. The dynamic blast response of water-backed sandwich panel was investigated using the LS-DYNA software. An analytical three-stage model was developed for the deformation history of water-backed sandwich panel subjected to shock loading in water. Blast resistance of water-backed sandwich panel was compared with monolithic plate of equivalent areal mass and air-backed sandwich panel with the same configurations. Water-backed sandwich panel exhibited the best deformation/damage resistant capability. Compared with air-backed sandwich panel, core material exhibited greater volumetric strain when the sandwich structure wetted on both sides. Overpressure in the water behind structure was reduced to about 7% by using sandwich structure over monolithic plate of equivalent thickness. Present study led to the apprehension of dynamic response of water-backed sandwich structure to underwater blast load, thereby developed useful guidelines for the design of blast-resistant structural systems.