Mechanical characteristics of biomimetic twisted honeycomb structures fabricated by powder bed fusion

Honeycomb structures have been widely used in aerospace and automotive applications due to their high efficiency, high strength and high specific stiffness. However, most of the reported publications have focused on the surface shape variations of honeycomb structures, and there is a lack of studies on the variations of honeycomb structures with respect to the internal cell walls (Z-direction). To address these issues, this study proposes to combine the torsional design of honeycomb and Bouligand structures to fabricate twisted honeycomb structures (THS) with cell wall (z-direction) variations using powder bed fusion technology. The THS (30°) exhibits excellent specific energy absorption (SEA) performance, and the SEA of THS (0°), THS (60°), and THS (90°) are reduced by 8.5%, 19.7%, and 37.3%, respectively, compared with that of THS (30°) structure, and the THS (30°) has better repeatability. The effects of structural parameters on the energy absorption performance were analyzed. At THS (30°), changing the number of unit cells, wall length and wall thickness has a large effect on the compression performance. The results show that the specific energy absorption performance of THS reaches a maximum value of 74.6 kJ/kg for the number unit cells n = 3, wall length l = 5 mm and wall thickness t = 1 mm.