Resistance of all-metallic honeycomb sandwich structures to underwater explosion shock

Abstract

All-metallic honeycomb sandwich structure is a new kind of ship protection structure, which has a broad application prospect in the field of ship protection. However, there is not enough research on the dynamic response of honeycomb sandwich structures under the actual underwater explosion load. The dynamic behavior and protective performance of honeycomb sandwich structures subjected to underwater explosion load were investigated, both experimentally and numerically in this paper. A backplane stiffened honeycomb sandwich structure and the corresponding buoyant box were designed and fabricated for the subsequent experimental study in a large open water pool. The structural response was numerically simulated using the coupled acoustic-structural approach (integrated in commercial FE code ABAQUS/Explicit). The numerical simulation results are in good agreement with the experimental measurements. Then, the deformation process and energy absorption characteristics of the honeycomb sandwich structure subjected to underwater explosion load were investigated. The effects of the load parameter (impact factor) and two geometric parameters (i.e., facesheet thickness ratio and core relative density) on the dynamic response of the sandwich structure were analyzed. Finally, the Pareto optimal designs with minimize value of non-dimensional areal density and minimize value of non-dimensional maximum deformation of the central point on back facesheet were obtained using the NSGA-Ⅱ algorithm. The results show that with the increase of impact factor, the overall deformation of the structure increases significantly. The honeycomb core is the main energy absorbing substructure during this process, and its energy absorption ratio gradually decreases. With the increase of either face sheet thickness ratio or core relative density, the deformation of the structure first decreases and then increases, accompanied by changes in deformation modes. The influence of core relative density is more significant. The optimized structures obtained from multi-objective optimal design effectively reduce the areal density and the maximum deformation, which can be used as a reference for the future design of honeycomb sandwich structures.