Analytical study on the low-velocity impact penetration of the fully-clamped foam-core composite sandwich panels

An analytical model based on Hamilton's principle is proposed to predict the load/displacement history, failure characteristics and energy partition of composite sandwich panels subjected to low-velocity impact of a projectile. Lagrangian functions based on the five-stage penetration process is developed, in which failure of each constituent is considered to demonstrate the progressive failure process. After the analytical model was validated against the experimental results, it was used to investigate the effect of core density and face-sheet stacking sequence on the impact response. Discussions showed that the impact resistance of the panel correlates strongly to the core density, while stacking sequence has minor effect on sandwich panel under low energy impact. Energy contribution of all components during impact penetration under different energy were studied to discuss the optimum configuration of the structure. The analytical model may provide a quick and reliable preliminary assessment in structure design and optimization.