Lattice reinforcement design method based on variable cross-section pillars

Body centered cubic (BCC) structure has excellent mechanical properties, but the stress concentration phenomenon at the nodes limits its further development in mechanical properties. At present, the method of adding spherical nodes or variable cross-section pillars is commonly used to alleviate stress concentration at nodes and achieve strengthening design of lattice structures, but there is a lack of research on the influence of the volume ratio of nodes to pillars on the strengthening effect. A new type of variable cross-section pillar based on trigonometric function reduction is designed, and a variable cross-section body centered cubic lattice (VC-BCC) lattice is designed. Dynamic node design is achieved by directly connecting the pillars to explore the optimal node to pillar volume ratio. Theoretical formula estimation of the volume of VC-BCC lattice is carried out, and based on the Timoshenko beam model, the equivalent elastic modulus of VC-BCC lattice is theoretically analyzed. A simplified model is established using the method of equivalent cross-section. Finite element simulation analysis was conducted on VC-BCC lattice with different proportions of node pillars, and lattice specimens were manufactured using selective laser melting technology for quasi-static compression testing. The experimental results show that there is little difference between theoretical calculations and simulation analysis. The maximum stress of the VC-BCC lattice structure is significantly reduced, and the equivalent yield strength is significantly improved. In all analyses, the VC-BCC lattice structure with a variable cross-sectional parameter of 0.6 exhibited excellent performance and had the best overall mechanical properties.