Dynamic mechanical behaviors and deformation mechanism of hybrid triply periodic minimal surface structures

The hybrid design strategy has proven effective for traditional strut-based lattice metamaterials to enhance their stability and energy absorption performance. However, previous studies have been insufficiently comprehensive in exploring energy absorption performance and other related aspects. Given the superior mechanical properties of Triply Periodic Minimal Surface (TPMS) structures, four different types of hybrid TPMS structures were designed and fabricated by fused deposition modeling (FDM) process. Quasi-static and dynamic experiments were conducted to investigate their mechanical response and deformation behavior under compression, with a focus on the impact of relative density, loading directions and loading speeds. Meanwhile, numerical simulations were supplemented according to the experimental arrangement to uncover mesoscopic information that cannot be directly obtained from experiments. The experimental and numerical results demonstrated that the hybrid structures exhibited distinct properties depending on the loading direction. As the relative density increased, the plateau stress of the hybrid structures increased significantly, while the deformation mode remained nearly unchanged. Compared to specimens compressed along the lateral direction, the hybrid structures subjected to axial loading presented higher plateau stress due to their uniform deformation. Additionally, the hybrid design mitigated the stress softening phenomenon in the post-yield response of TPMS structures. Notably, the hybrid TPMS structures demonstrated superior specific energy absorption (SEA) and energy absorption efficiency compared to uniform structures, with SEA shows an improvement of 15 % to 59 % compared to the uniform Gyroid structure, and an improvement of 5.6 % to 72.4 % compared to the uniform Diamond structure. These findings provide potential prospects for application in the field of impact resistance.