Mechanical properties of bionic lattice and its hybrid structures based on the microstructural design of pomelo peel

Bionic design has been widely used in real life, while providing ideas for innovative design of structures. In this work, a bionic lattice structure (Y-structure) with negative Poisson's ratio effect is obtained based on the principle of bionic design by taking design inspiration from the microstructure of pomelo peel. Meanwhile, in order to reduce the fabrication difficulty, the Y structure is combined with the BCC structure to obtain four overall lattice structures containing the Y structure. The required samples are prepared by additive manufacturing technique using PA2200 as the matrix material. Quasi-static compression tests are performed on the specimens at room temperature, and the mechanical properties and energy absorption capacity of the bionic lattice structure are examined under different compression directions, considering the anisotropy of the structure. Through the experimental results, it can be found that, compared with the traditional BCC structure, the four lattice structures containing the bionic lattice show obvious anisotropy, and exhibit good mechanical properties in different directions, while the energy absorption capacity is also generally improved. However, the change in the occupancy ratio of the BCC structure has a significant effect on the mechanical properties of the mixed lattice structure. The results obtained in this study can provide valuable references for further creative new developments of lattice structures based on bionic principles.