Dynamic compressive behaviour of functionally graded TPMS lattice structures

Triply Periodic Minimal Surface (TPMS) lattice structures have gained attention due to their inherent high strength-to-weight ratio and tunable mechanical properties. The ability to further enhance the performance of these structures by incorporating functional grading has enabled the development of enhanced protective structures. This study evaluates the dynamic compressive response of five different functionally graded TPMS lattice structures with Gyroid and Diamond TPMS geometries. The samples were additively manufactured using the impact resistant material Acrylonitrile Butadiene Styrene (ABS) and were subsequently subjected to low-velocity impact using a drop-weight impact facility. Force-displacement responses, front-face deformation profiles, cross-sectional fracture details and energy absorption properties were compared under each grading configuration. The results showed that the Positive Radially Graded (PRG) configuration which is bio-inspired by the tree trunk, outperformed the rest of the grading configurations in terms of the overall energy absorption response. Gyroid TPMS structures achieved a lower peak impact force, higher deformability and higher specific energy absorption showcasing enhanced crashworthiness compared to the Diamond TPMS geometry.