Topology optimization design and research of lightweight biomimetic three-dimensional lattice structures based on laser powder bed fusion

In this paper, a topological structure based on the three-dimensional (3D) bionic lattice method had been used to optimize the structure of the U-Shape ring, a typical type of load-bearing structure, in order to minimize the weight of the structure, while ensuring the U-Shape ring's sufficient strength and stiffness. Three kinds of 3D lattice sandwich structures for U-shaped sample were established and analyzed by the way of computer aided design (CAD) and finite element analysis (FEA). The pyramidal sandwich unit had been adopted to the lightweight design of the U-shaped sample, which had been optimized from the full-rod unit structure into the pyramid unit with “rod system and thin wall”. At the same time, according to the process characteristics of laser powder bed fusion (LPBF), the local structure had been optimized again, which not only met the technical requirements of LPBF, but also improved the equivalent strength and stability of the interface between element core and U-shaped inner wall. Through the above measures, the weight of the U-Shape bearing ring could be reduced by nearly 30%. Then the U-shaped load-bearing parts had been made by the LPBF process, and a special test device had been designed to test the mechanical properties of the samples. The results showed that the loading test was basically consistent with the FEA, and both met the design requirements. The design of 3D bionic lattice spatial structure used in this paper effectively solved the problem of the loss of strength and stiffness caused by the lightweight structure. The research work of this paper can be used as a reference for those who are engaged in lightweight structure design.