Influence of core gradation strategy on the blast mitigation performance of multi-stage functionally graded honeycomb sandwich panels

Blast attacks have been increasing day by day in recent decades. Due to the excellent energy-absorbing ability of honeycomb sandwich panels, they are widely used for making protective structures against blast attacks. An enhancement in the blast mitigation performance of a sandwich panel without changing its space occupancy and mass is always a challenging task. Hence, in the present dynamic explicit numerical study, a series of distinct functionally graded patterns are implemented to boost the blast resistance of decent-performing ungraded multi-stage honeycomb sandwich panels without changing their volume occupancy and mass. All the sandwich panels were subjected to air blast loads of 1-2 kg of spherical trinitrotoluene for a 100 mm fixed stand-off distance. Various patterns of cell and thickness gradations were implemented with the same combinations of honeycomb core layers’ relative densities to find out an effective gradation pattern. The results obtained showed that the positive cell-graded pattern using multi-stage functionally graded honeycomb sandwich panels effectively reduced the back-face sheet deflection and was potentially applicable for armored vehicle and naval ship parts.