In this study, a linear, S-type, and C-type gradient shell-lattice structure was designed based on the uniform shell-lattice structure of a spiral type minimal surface, and corresponding finite element models were established using aluminum alloy (Al-Si10-Mg) as the material. A theoretical numerical analysis of mechanical properties based on three-point bending was conducted on four types of shell-lattice structures, and the results were compared with finite element analysis. The maximum displacement and maximum allowable load of plastic failure under three-point bending were analyzed for the four types of shell-lattice structures. The samples were processed using selective laser melting (SLM) technology and subjected to three-point bending tests, which were in good agreement with the results of finite element analysis. The conclusion indicates that the maximum allowable load of S-type, linear, uniform, and C-type shell-lattice structures decreases sequentially. The use of single linear variable density design and quadratic nonlinear variable density design perpendicular to the loading direction can significantly improve the maximum allowable load of shell-lattice structures. However, the order of variable density design for shell-lattice structures cannot determine their bending performance. Therefore, specific analysis should be conducted on the physical distribution of lattice structures in different variable density designs.
Hao et al. (Mon,) studied this question.