A study of multi-stage energy absorption characteristics of hybrid sheet TPMS lattices

Triply periodic minimal surface (TPMS) has many excellent properties, such as stable energy absorption, a high specific strength, a large surface area, etc. The functional multi-stage design and research of TPMS lattices were carried out to improve the mechanical performance. The deformation modes and curves of three uniform TPMS lattices (Primitive, Gyroid, and Diamond) and their hybrid lattices were analyzed by quasi-static compression experiments and numerical simulations. Based on the uniform TPMS lattice, hybrid sheet TPMS lattices were designed to realize the multi-stage energy absorption (multi-stage platform) and multi-stage protection integrated porous structure. The two-stage energy absorption characteristics of hybrid sheet TPMS lattices were systematically studied, and the effects of hybrid TPMS composition, width of the transition layer, relative weight, and hybridization method on the multi-stage energy absorption were obtained. The results indicated that the Gyroid-Diamond hybrid lattice performed the best, with the specific energy absorption (SEA) increasing by 30.48% and 0.51%, and the yield stress decreasing by 14.01% and 30.07%, respectively, as compared to the single TPMS lattice. Width of the transition layer has little effect on the two-stage energy absorption. The relative weight will shorten or widen the length of the two-stage platform stress. The hybridization method shows that the sequence hybridization along the loading direction based on the TPMS lattice yield strength is the best arrangement to achieve the effect of multi-stage energy absorption. Finally, the three-stage energy absorption characteristics of hybrid Primitive-Gyroid-Diamond lattices are further studied. The results show that with the increase of layers of TPMS lattices, the fluctuation of the multi-stage curve and the yield stress will increase.