Cellular materials, such as aluminum foams, have proven to be excellent energy absorbents. They can be used as crushable core in sacrificial cladding (SC) for blast load mitigation. In this study, the blast absorption capacity of a brittle mineral foam-based SC is investigated through finite element modeling using the LS-DYNA software. The experimental set-up used consists of a rigid steel frame with a square cavity of 300 mm x 300 mm in the center The structure to be protected is simulated by a thin aluminum plate clamped into the rigid steel frame. The blast load is generated by 20 g of C4 high explosive set at a distance of 250 mm from the center of the plate. The blast absorption capacity of the considered SC is evaluated by comparing the maximum out-of-plane displacement of the center of the plate with and without the protective brittle mineral foam. The presence of the brittle mineral foam reduces the maximum out-of-plane displacement of the center of the plate at least by a factor of two. The brittle mineral foam is modeled both in solid elements and smoothed-particle hydrodynamics (SPH) by using Fu Chang's constitutive material law based exclusively on the results of quasi-static compression tests of the foam and a phenomenological relationship between stress, strain and strain rate. The SPH model predicts the maximum out-of-plane displacement of the center of the aluminum plate with an average relative error of 5% with respect to the experimental values.

This paper presents a study on the dynamic behavior of thin aluminum plates subjected to consecutive fragment impact and blast loading. To this end, two separate experimental setups are used. In the first setup, 2 mm thick aluminum plates EN-AW-1050A-H24 were subjected to the ballistic impact of fragment-simulating projectiles (FSPs). Experiments were carried out for FSP calibers of 7.62 mm and 12.7 mm considering both single impact and triple impacts with variations in the spacing of the impact locations. The out-of-plane displacement and in-plane strain fields were measured using digital image correlation (DIC) coupled to a pair of high-speed cameras in a stereoscopic setup. In the second setup, a subsequent blast loading was applied to the perforated plates using an explosive-driven shock tube (EDST). After the plates are perforated, the strain field around the holes depended on the caliber, the impact orientation of the FSP, and the distance between the impact locations. When the blast loading was applied, cracks tended to appear in areas of strain concentration between the perforated holes. It was found that the relative distance between the holes significantly influences the target’s response mode.