Characterization of edge effects of composite lattice structures

To analyze the mechanical behaviors of composite lattice structures with finite sizes and strengthened edges, periodic expansion method was developed to get the corresponding equivalent infinite periodic structures. Finite element method was also adopted to testify the theoretical predictions. The strengthened edges greatly influence the properties of composite lattice structures made up of only several layers of unit cells. Reductions of the specific stiffness and strength of the lattice composites in most cases stem from the mass enhancement. Made up of more than 10-20 unit cell layers, the lattices possess nearly identical properties of the intact composite lattice structures and the edge effect is small enough. Compared with the weak edges, the major advantage of strong edges is that they distribute loads more extensively and evenly and greatly decrease the localization of strains and stresses on the boundaries under concentrated loads.