Designable mechanical properties of modified body-centered cubic lattice materials

Lattice materials possess broad application potential in many engineering fields due to their excellent mechanical properties. In this paper, a thorough investigation is carried out for the lattice materials with the generalized body-centered cubic (BCC) cell geometry. The investigated geometry variations include (1) adding additional reinforcement bars along several cell edges, and (2) offsetting the central vertex of the cubic cell that the oblique beams connect. The influences of the cell geometry on the stiffness, the Poisson's ratio, the energy absorption capacity and the deformation pattern of the generalized cubic lattice are ascertained through extensive theoretical and finite element (FE) numerical analyses. The results indicate that adding reinforcement bars along the loading direction can effectively enhance the stiffness and strength, but does not significantly change the deformation pattern as depicted by the shape of shear bands. The additional bars perpendicular to the loading direction can largely influence the Poisson's ratio, making it possible to approach unity. It is found that a modified BCC lattice with properly offset central cell vertices achieves an optimal energy absorption capacity that is about 2.26 times of traditional BCC lattice. This work could provide a comprehensive reference for the mechanical properties of the most generalized BCC lattice materials.