Mechanical properties of 3D printing novel bionic hierarchical cellular structure inspired by Raphia seed: Experimental, simulation and theoretical investigation

Cellular structure attracts much attention due to its excellent energy absorption capacity and lightweight. In this study, inspired by the Raphia seed, a 3D printing novel bionic hierarchical cellular structure with different order structure parameters is proposed. The effect of different order structure parameters on the mechanical properties of the bionic cellular structure are studied by compression experiments, numerical simulation and theoretical model. The results show that the mechanical properties of the bionic cellular structure have a linearly with the thickness of cell wall, but a non-monotonic relationship with the thickness of tube wall and the diameter of circular hole. Compared with other typical cellular materials, the bionic cellular structure exhibits superior energy-absorbing performance. Besides, the deformation modes of the bionic cellular structure are dominated by order structure parameters, and there are “horizontal”, inclined shear mode and “V” shear deformation modes. The distribution of strain field is closely related to mechanical properties and deformation modes of the bionic cellular structure. At last, the semi-empirical theoretical models of SEA, relative elastic modulus and relative platform stress of the bionic cellular structure are established. This study provides a good option for improving the load-bearing capacity and energy absorption performance of lightweight cellular structures.