Combining multiple lattice-topology functional grading strategies for enhancing the dynamic compressive behavior of TPMS-based metamaterials

Recent developments in additive manufacturing technology have enabled the precise fabrication of intricate lattice materials, also known as metamaterials, for various engineering applications, particularly those involving dynamics. Lattice materials, consisting of sheet-based triply periodic minimal surface (TPMS) structures, have been extensively studied for their mechanical performance under quasi-static and dynamic loading conditions. However, less attention has been given to assessing the effect of grading the lattice topological properties for improved compression loading. Consequently, this paper investigates the effect of topology hybridization, periodicity gradation, cell compaction, and combining multiple functional grading strategies on the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. We conducted quasi-static compression tests to evaluate different regular sheet-based TPMS architectures and select the most promising candidates for topology-functional gradation. Subsequently, numerical simulations were performed to analyze the compressive deformation behavior and properties of functionally graded sheet-based TPMS lattice materials alongside the uniform topologies. This test showed that Schwartz Diamond (Du) and Face-centered Rhombic Dodecahedral (FRDu) lattice structures exhibit superior compressive properties in quasi-static conditions. Furthermore, simulations revealed that the lattice topology and grading strategy significantly influence the quasi-static and dynamic compressive behavior of sheet-based TPMS lattice materials. Specifically, the IWPu topology showed a notable increase in compressive strength and energy absorption compared to the other lattice types as the strain rate increased. Hybridizing Du and FRDu topologies produced a strictly layer-wise deformation pattern, resulting in improved quasi-static and dynamic compressive properties compared to the elementary topology. However, a superior uniaxial compressive modulus and strength were achieved by gradually adjusting the periodicity of a single topology (Du) while maintaining the same relative density. The combination of relative density and periodicity gradation led to more desirable deformation behavior while enhancing the overall compressive properties of the metamaterial, regardless of the strain rate.