Low-velocity impact response of sandwich panels with layered-gradient metal foam cores

The low-velocity impact response of square sandwich panels (SPs) with three-layer metal foam core was examined via analytical and numerical approaches. Taking into account the core arrangements, the analytical model is formulated by employing an innovative yield criterion, to predict the impact force and deflection responses. The accuracy of the analytical predictions was confirmed through finite element (FE) results, and the influences of the core distribution, impact position, as well as core thickness on the impact behaviour of SPs were discussed. It is shown that the graded core SP exerts slightly inferior impact resistance than the uniform core SP. The closer the impact position is to the clamped boundary, the smaller the deflection of the bottom face-sheet and the greater the impact force. As the thickness of the core increases, the proportion of energy absorption attributed to the core also increases. Eventually, the analytical formula was used to generate a design chart for the lightweight configuration, providing geometric optimization pathways.