Bending Response of Carbon Fiber Composite Sandwich Beams With Pyramid Lattice Cores

ABSTRACT Thanks to their high specific strength and stiffness, composite pyramid lattice core structures are widely used in aerospace applications. However, the composite sandwich beams still face many challenges when subjected to bending loads. This study uses theoretical, experimental, and numerical simulation methods to investigate the failure behavior of composite pyramid lattice core structures with different configurations, core densities, and panel thicknesses under three‐point bending loads. Failure modes included panel crushing, panel wrinkling, core crushing, core buckling, node fracture or degumming between panel and core. Comparative analyses were carried out for each group of specimens, and the results showed that the introduction of aluminum alloy reinforcement frames significantly improved the bending performance of the lattice sandwich structures; furthermore, with increasing core density and panel thickness, the failure mode changed and the failure loads of the lattice sandwich structure under three‐point bending loads increased. The most important thing about this work is that it provides a suitable approach for designing and optimizing composite pyramid lattice core structures to improve their bending strength.