Plastic behavior of foam-filled hexagonal core sandwich beams

Analytical modeling and numerical simulations are employed in this study to examine the plastic behavior of fully clamped foam-filled hexagonal core sandwich beams (FHCSBs) under transverse loading. A yield criterion is developed for the FHCSB cross-section by considering the combined strength contributions of the folded plates and the metallic foam filler. By coupling this criterion with the associated flow rule, an analytical model is developed to predict the large-deflection behavior of FHCSB, specifically accounting for the interaction between bending and axial stretching. To verify the theoretical framework, numerical calculations using Abaqus/Explicit software are performed. The results show that the analytical predictions for post-yield response match the numerical results for both mid-span and offset loading cases. Additionally, a parametric study investigates how face-sheet thickness, foam strength, and cell inclination angle influence the structural performance. The analysis indicates that face-sheet thickness is the primary factor determining the membrane hardening rate, whereas the hexagonal core configuration offers a stable cushioning effect during early-stage deformation. This analytical approach provides an effective tool for assessing the load-carrying capacity and energy absorption of FHCSB structures.