A Study on Effective Compressive and Shear Properties of Tetrahedral Lattice Materials

Abstract

Tetrahedral lattice materials can be used as the core of a sandwich structure. The properties of tetrahedral lattice materials can be controlled by modifying their geometrical parameters and relative density. In this paper, a tetrahedral lattice structure deformation mechanism-based theoretical analysis model is established to predict the effective mechanical properties of the structure under compressive and shear loadings. The analytical solutions are subsequently verified by finite element analysis of a large-scale lattice material model. Based on the obtained results, the effects of the geometrical parameters, relative density, and shear deformation are discussed. At a specific relative density, as strut inclination angle increases: (1) the effective compressive modulus in the z-direction increases; (2) the effective compressive modulus in x- and y-directions, and the effective shear modulus in xy-, xz-, and yz-directions firstly increases but then decreases; (3) the effective Poisson’s ratios [Formula: see text] and [Formula: see text] increase, whereas, [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] decrease. With an increase in relative density, the effective compressive and shearing modulus increase, the effective Poisson’s ratios remain constant, [Formula: see text] and [Formula: see text] are always equal to 0 when the strut inclination angle is [Formula: see text]. The effect of shear deformation on the effective mechanical properties increases as the slenderness ratio increases. The predicted effective properties enable the tetrahedral lattice unit cells to be treated as “material” in the design and analysis process.