Quasi-static crushing analysis of doubly-curved sandwich shells with microlattice core: 3D-numerical simulation

Lightweight sandwich structures with microlattice cores have emerged as promising candidates for aerospace and automotive applications due to their high stiffness-to-weight ratio and superior energy-absorption capability. However, most previous studies have focused on flat configurations, and the mechanical response of doubly-curved sandwich shells with microlattice cores remains insufficiently explored. This study presents a numerical investigation into the quasi-static crushing behavior of flat and doubly-curved sandwich shells incorporating microlattice cores. The investigated structure consists of two metallic face-sheets bonded to a lightweight microlattice core with a body-centered cubic (BCC) topology, designed to enhance stiffness-to-weight ratio and energy absorption efficiency. Using finite element modeling with ABAQUS, nine distinct panel configurations were analyzed, varying in face-sheet thickness and curvature. The microlattice core was modeled using body-centered cubic (BCC) unit cells with both solid and beam elements, validated against experimental data. Results show that both curvature and face-sheet thickness significantly influence structural performance. Increased face-sheet thickness improves peak load capacity and stiffness, while doubly-curved panels exhibit enhanced load-bearing capacity compared to flat panels due to curvature-induced membrane stresses. The study establishes that doubly-curved sandwich shells with microlattice cores offer mechanical advantages over flat counterparts, especially when optimized for face-sheet thickness and curvature.