Measurement of Damping Ratios of Hollow Sandwich Slabs Under Close-Contact Blast Load

To prevent structural damage in a contact explosion, the blast load must be discharged without damaging the structure. Contact blast tests were conducted in our study using TNT-equivalent explosives of between 125 g and 350 g, and prefabricated hollow-core plates were utilized to evacuate the blast load. Two types of hollow sandwich plates (HSPs) were designed with reference to this experiment. Then, contact and close-contact explosions were carried out on HSP samples using between 350 g and 1100 g of TNT-equivalent explosives. Comparisons were conducted using pressure/time charts from the blast tests and numerical analyses of the smoothed particle hydrodynamics (SPH) model. As a result of the experiments, the limit blast load that the sandwich slab structure can carry while maintaining its stability during a contact blast was determined, and it was found that drainage took place on the slab at a level of 10% of the limit explosion pressure load it could carry. This mitigated the explosive energy of the hollow structure by draining it from the voids without compromising the integrity of the structure.