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 degrees) exhibits excellent specific energy absorption (SEA) performance, and the SEA of THS (0 degrees), THS (60 degrees), and THS (90 degrees) are reduced by 8.5%, 19.7%, and 37.3%, respectively, compared with that of THS (30 degrees) structure, and the THS (30 degrees) has better repeatability. The effects of structural parameters on the energy absorption performance were analyzed. At THS (30 degrees), 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. (Honeycomb structures are widely used in aerospace and automotive applications because of their high efficiency, high strength, and high specific stiffness. However, most of reported publications focus on surface shape variations of honeycomb structures and the lack of honeycomb structures with variations in the internal cell wall (Z direction). Facing these problems, this investigation has proposed to create twisted honeycomb structures (THS) with internal cell wall (Z-direction) variations by combining the torsional design of honeycomb and Bouligand structures using powder bed fusion. In this study, the effects of different torsion angles on the quasistatic mechanical response and deformation patterns of the honeycomb structures have been evaluated via conducting axial compression tests. Numerical simulations are performed using the ABAQUS software and compared with experimental results to verify the accuracy of the simulations. In addition, the effects of the construction parameters on the energy absorption performance have been analyzed. Experimental results show that the THS with a torsion angle of 30 degrees exhibit the best mechanical properties with good repeatability. The specific energy absorption performance of THS reaches a maximum of 74.6 kJ/kg for structural parameters of the number of unit cells n = 3, wall length l = 5 mm, and wall thickness t = 1 mm)