Effective strut-based design approach of multi-shaped lattices using equivalent material properties

We propose an effective approach for designing a multi-lattice structure (MLS) that simultaneously considers local densities and the fillet-joint shape of struts to express practical equivalent material properties. The density of each cell is optimized by changing the strut diameter and fillet-joint radius according to loading conditions. The equivalent material properties of MLS, such as elastic modulus and shear modulus, are calculated based on a computational homogenization method. Finite element analyses of the full-shape and homogenized lattice model under external compressive load are conducted to evaluate the equivalent material properties. We also designed an optimized three-point bending structure using the proposed method. Based on the results of the topology optimization, three types of lattices with different relative densities are designed in a local zone considering local deformation modes. The result of this work shows that multi-lattice bending structure has about 86.9 % higher strength than that of a uniform BCC lattice structure with the same weight.