Homogenization-based topology optimization for self-supporting additive-manufactured lattice-infilled structure

Lattice-infilled structures possess prominent properties at relatively low mass, which are of great significance in academic investigations and engineering fields such as aerospace science and biomedical applications. However, both the macro geometry and relative density distribution of the infilled microstructure exert considerable influence on performances of lattice-infilled structure and the structural manufacturability needs to be considered. In this work, an optimization design methodology for self-supporting additive-manufactured lattice-infilled structures is proposed, in which the macro geometry and relative density distribution of the microstructure are concurrently optimized. Microstructure is infilled after topology optimization and octree structure is introduced into the boundary layers of the lattice core to support the top shell during fabrication. The effectiveness of the proposed optimization design method for self-supporting additive-manufactured lattice-infilled structures was proved by both three-point-bending test and full-scale finite element simulation. Compared with the uniformly-infilled sample, mass-specific stiffness and strength of the topologyoptimized sample were improved by 41.2% and 112.1%, respectively. The proposed design method for lattice-infilled structures provides potential for designing additive-manufactured high-performance lightweight structures, which will broaden the boundaries of lattice structure in engineering applications.