Computational analysis and optimization of foam-filled honeycomb core sandwich structure under air blast loading

Developing a sandwich structure with a lightweight and high energy absorption capacity is crucial to mitigating shock waves when subjected to blast loading. In this present study, a novel double-core hexagonal sandwich structure filled with aluminum (Al) foam is used to investigate the structural response under blast loading subjected to 1 to 3 kg of charge of TNT kept at a stand-off distance (SoD) of 100 mm. The investigation and its assessment are mainly focused on the deflection of the face sheets and the energy absorption capacity of the panel. The Johnson-Cook plasticity model and crushable foam hardening are used in stainless steel and Al foam, respectively, to examine the performance under blast loading. The conventional weapons effect programme (ConWep) method is employed for numerical modeling and blast load analysis. Subsequently, a comparison is made between the blast resistance of the double-core sandwich structure and that of the experimental results of the single-core sandwich structure obtained from previous literature. Further, to improve the performance of the developed double-core sandwich structure, an optimization study is conducted using the genetic algorithm (GA) and the non-dominated sorted genetic algorithm II (NSGA-II) to explore single- and multi-objective problems, respectively. The results showed that for the single-objective optimization, the maximum back facesheet deflection is reduced by 13.35% at constant mass compared to the initial design, while for the multi-objective optimization, five optimal design values are obtained from the Pareto front and can be seen as a potential replacement for single-core panels. The novel structure developed in this study will be used in defense, automotive, and aerospace applications.