The Mechanical Properties of Hierarchical Truss-Walled Lattice Materials

To construct a hierarchical lattice structure (HLS), truss wall is introduced into ordinary lattice structure (OLS). Young's modulus, yield strength and buckling stress of HLSs were evaluated theoretically. Failure maps of different HLSs were plotted and compared based on the theoretical analyses. It is indicated that mechanical behaviors of hexagonal HLSs made of triangular lattice walls can be greatly enhanced by the hierarchical wall structure, while properties of triangular HLSs are weakened, except the anti-buckling resistance. When HLSs are made of bending-dominated honeycomb walls, their properties will be reduced, indicating that hierarchical structure should be appropriately designed to make ultra-light structures benefit from this construction. This viewpoint is strengthened by the discussions on the performances of high order lattice structures, where only bending-dominated HLSs with stretching-dominated lattice wall benefit from the hierarchy.