Network-based and sheet-based Gyroid lattice structures with different gradient directions: manufacture, mechanical response and energy absorption

To investigate the effect of gradient direction on mechanical properties and energy absorption capability of Gyroid lattice structures (GLSs), network-based and sheet-based lattice structures (G1-N768, G2-N768, G1-S768, G2-S768) of different gradient directions with an average porosity of 70% were established. The Al-Si10-Mg samples were manufactured through selective laser melting (SLM). Through compression tests and finite element analysis (FEA), the energy absorption, deformation behavior, and mechanical properties of the GLSs were evaluated. The data exhibited good consistency, and the deviations of yield strength, elastic modulus, plateau stress, densification strain and energy absorption could be controlled at about 10%. The results indicated that whether it is network-based or sheet-based GLSs, by changing the gradient direction, the deformation behavior could be transformed from layer-by-layer deformation (G1-GLSs) to uniform deformation (G2-GLSs), and thus realize the regulation of mechanical properties. At the same time, due to different topological configurations, stretch-dominated sheet-based GLSs (G1-S768, G2-S768) exhibited higher energy absorption capability and mechanical properties than bending-dominated network-based GLSs (G1-N768, G2-N768), and the energy absorption, yield strength and elastic modulus increased by 93.7%, 80.8% and 66.7%, respectively. In addition, the introduction of the Johnson–Cook model has effectively simulated the failure behavior of GLSs. This paper can offer theoretical guidance for the subsequent performance regulation and application of functionally graded GLSs.