Evaluation of the dynamic response of triply periodic minimal surfaces subjected to high strain-rate compression

Architected cellular structures based on triply periodic minimal surfaces (TPMS) have attracted significant attention due to their lightweight, superior, and controllable mechanical properties. Such lattice structures can be potential candidates for high specific energy absorption (SEA) applications. In this study, five TPMS sheet-based structures (Gyroid, Primitive, IWP, Diamond and Fisher-Koch) were designed, fabricated, and tested under quasi­-static and dynamic loading conditions. Laser powder bed fusion (L-PBF) is employed to facilitate the fabrication of these complex structures using stainless steel (SS316L) at three different relative densities. Scanning electron microscopy (SEM) and micro­ Computed Tomography (micro­CT) were utilized to assess the quality of the printed structures. The dynamic compressive behavior is investigated by conducting direct impact compression tests utilizing a Direct Impact Hopkinson Bar (DIHB) at a strain-rate of 2057 s−1. Quasi-­static tests are also performed at a strain-rate of 0.005 s−1. The quasi-static and dynamic mechanical responses are then compared to explore the changes in plateau stress and specific energy absorption values of the five TPMS lattices in these two loading regimes. Furthermore, the effects of changing both architecture and relative density on the properties of lattice structures are investigated. The results show that all five topologies exhibit an enhanced mechanical performance under dynamic loading. In fact, Diamond structure demonstrates the highest SEA value of 35.57 J/g under the high strain-rate loading condition, in comparison to 30.85 J/g in the quasi-static loading. This study suggests that TPMS structures could be potential candidates not only for quasi­-static, but also for dynamic applications related to a high strain-rate loading.