Dynamic response analysis of multi-layered core sandwich structures for protection against underwater explosion

This numerical study investigated the dynamic response of multi-layer core sandwich structures subjected to underwater explosion and suggested beneficial mass-distribution of cores. From previous findings, submerged protective structures experience three stages. These are the FSI stage, core compression stage, and structural beam stretch-bending stage; energy dissipation performance was influenced by the mass distribution. In this regard, three types of multi-layer core designs, a positive-gradient core, a negative-gradient core, and a uniform core were considered for the cores of sandwich structures. Their structural responses at the three stages of underwater explosion were analyzed by constructing two kinds of FE models, a one-dimensional free-standing sandwich model and a clamped sandwich beam model. Transmitted impulses in the FSI stage and deflections of sandwich beams were calculated. Consequently, the positive-gradient core behaved favorably at the first two stages, resulting in the smallest beam deflections.