Geometry effect on mechanical properties and elastic isotropy optimization of bamboo-inspired lattice structures

Abstract

Inspired by the geometry of bamboo, this study proposes a novel bamboo-inspired body-centered cubic (B-BCC) lattice structure consisting of tapered and hollow struts. Using representative volume elements applied with periodic boundary conditions, the mechanical properties and deformation behaviors of the B-BCC lattice structures are thoroughly evaluated by considering a large number of combinations of geometric parameters and volume fractions. Results reveal that the geometric parameters highly influence the deformation behavior of the B-BCC lattice structures under uniaxial compression (e.g, from bending- to stretching-dominated) but little under shear load. For this reason, tunable elastic modulus across a broad range can be realized via adjusting the geometric parameters and elastic isotropy can be obtained across all volume fractions. On this basis, a combination of artificial neural network and elastic isotropy optimization is proposed to obtain the isotropic B-BCC lattice structures with superior elastic modulus. The optimization results show that the elastic modulus of the isotropic B-BCC lattice structures increased by 271.24–1335 % and 17.72–43.63 %, as compared to the original BCC and isotropic hollow BCC lattice structures, respectively. Finally, the multi-layer simulation and compression experiments are applied to validate the optimization results. Good agreements are observed comparing the numerical and experimental results, demonstrating the effectiveness of the proposed bamboo-inspired design and optimization method for lightweight applications with desired properties.