Numerical Investigation of Auxetic Sandwich Plates under Blast Loading

Auxetic sandwich structures are emerging as promising candidates for blast mitigation due to their lateral contraction response under compression, which enhances load redistribution and energy dissipation. This study numerically investigates the blast response of a sandwich plate with a re-entrant auxetic core to understand its deformation and energy absorption mechanisms under severe impulsive loading. The finite element simulations are carried out in ABAQUS using the Dynamic Explicit solver. The metallic face sheets and the auxetic core are modelled with S4R shell elements, and strain rate-dependent material behaviour is incorporated through the Johnson–Cook constitutive parameters along with its damage criteria. The blast load is applied using the CONWEP approach to simulate an air-borne explosive with different shock factors. The computational model is initially validated with appropriate benchmark data from the literature. A parametric study is then performed by varying the geometric parameters of the re-entrant unit cell as well as the shock factor of the blast load. The structural response is examined in terms of specific energy absorption (SEA), plastic dissipation, and the maximum displacement of the front and back face sheets. The findings from this research aim to provide insight into the role of auxetic geometry on blast resistance characteristics of lightweight sandwich structures.