Stiffness design of a multilayer arbitrary BCC lattice structure with face sheets

In this paper, a theoretical stiffness design approach for a body-centered cubic (BCC) lattice structure is proposed. Although numerous studies have focused on lattice structures, particularly BCC lattice structure, there are still some issues that must be further investigated. Homogenization method is always followed that the mechanical properties of lattice structure can be achieved by directly solving the unit cell, since the structure is a periodically repeated sequence of a unit cell. However, the equivalent modulus varies a lot with different array configurations from our study, which indicates that the spatial array configuration also has an important influence on the equivalent mechanical properties. In this paper, “large unit cell” assumption is used to characterize the equivalent modulus of the lattice structure considering array configuration effect, and then validated using the finite element method (FEM) and experiment. The results demonstrate that the mechanical properties vary significantly for different array configurations, even those with the same unit cell topology. Furthermore, the proposed method is extended to an arbitrary BCC unit cell to broaden its application for stiffness design of engineering parts. This research provides a guidance for the stiffness design of lightweight lattice structures.