Numerical investigation of the response of I-core sandwich panels subjected to combined blast and fragment loading

The LS-DYNA software was employed to investigate the dynamic response of I-core sandwich panels under combined blast and fragment loading. The combined blast loading was simulated by placing pre-fabricated fragments at the bottom surface of bare explosive. To facilitate evaluating the synergistic effect under combined blast loading, the resistance of sandwich panels under bare blast loading was also assessed. The results demonstrated that the damage caused by combined blast loading was more severe than that by bare blast loading. The roles of charge mass, face-sheet configuration and core configuration on the deformation/failure behavior and energy absorption characteristics of panels were analyzed and discussed in detail. Under combined blast loading, the panels exhibited a perforation and tearing failure mode accompanied by structural fragments from failed front face. The charge mass is relevant to whether the residual momentum of fragments is large enough to penetrate the back face. The face-sheet configuration that had thick front face and thin back face was favorable in mitigating the damage response. The core configuration with dense core webs provided more assistance in preventing the appearance of failure pattern with a large connected region. The face-sheet configuration and core configuration have negligible influence on the total energy absorption, but they would redistribute the energy dissipation among each panel component. Furthermore, the comparisons of blast resistance between sandwich panels and conventional monolithic counterparts were made. It turned out that the sandwich panels experienced lower level damage failure on back face but dissipated similar energy relative to equivalent solid plates.