Energy dissipation of sand-filled TPMS lattices under cyclic loading

Abstract

• loading behaviors of three sand-filled TPMS were thoroughly investigated. • Sand-filled TPMS had superior energy dissipation than hollow TPMS. • P100 % improved most compared to hollow structures among the P, D, and G lattices. • Energy absorption of P lattices under three loading conditions was investigated. A novel recoverable energy-absorbing structure for cyclic loading is introduced in this study: a sand-filled Triply Periodic Minimal Surface (TPMS) lattice. The mechanical properties of these lattices were systematically investigated across different architectures—Primitive (P), Gyroid (G), and Diamond (D)—along with varying filling ratios and sand particle sizes. Additionally, the effects of resting time and loading speeds were analyzed. It was demonstrated that sand-filled TPMS lattices significantly enhance energy dissipation compared to their hollow counterparts, showing improvements of 150 % for P, 70 % for G, and 30 % for D. Notably, all sand-filled TPMS lattices perform similarly, although the P structure exhibits the lowest energy dissipation on its own. The damping capacity of both sand-filled and hollow TPMS lattices was found to improve with extended resting time. However, the sand-filled structures require longer recovery time due to complex interactions between sand particles and TPMS walls, along with the internal friction between sand particles and the resistance to rearrangement. As loading speed increased, the specific energy dissipation ( SED ) of the hollow P lattice was shown to improve by 98.2 %, while that of the sand-filled P100 % lattice increased by 41.8 %, indicating greater sensitivity of the hollow structure to loading speed. This is because the solid-like P100 % structure lacks the internal structure of porous P0 % lattice that creates the inertia effects of the cell walls, more localized deformation and stress wave propagation, reducing the impact of higher speeds. Moreover, the structure filled with medium-sized sand particles has higher energy dissipation efficiency because they offer an optimal balance between inter-particle cohesion and flowability, allowing effective void-filling without excessive compaction or loss of mobility. Overall, the sand filling can alleviate the buckling of the walls and strain concentration, thus enhancing energy dissipation without sacrificing mechanical degradation. These findings provide valuable insights into the design of sand-filled TPMS lattices for improving energy dissipation and recoverability under cyclic loading conditions.

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