Crystal-inspired cellular metamaterials with reduced Poisson’s ratio as analogues of TPMS

Abstract

Additive manufacturing of cellular metamaterials appears to be promising in weight reduction for transportation and advanced civil engineering applications. It provides improved energy efficiency, reduces fuel and energy consumption, and CO₂ emissions. Crystal-inspired materials inherit their TPMS (Triply Periodic Minimal Surface)-like architecture from carbon allotropes with high sp³ and sp² hybridization at the microscale. However, it is still uncertain whether materials with a TPMS topology derived from crystal structure data can surpass the properties of ideal TPMS. Our findings indicate that this is feasible using new approach in design of crystal-inspired structures for SC1 carbon and octacarbon (supercubane)-derived metamaterials in terms of the Poisson’s ratio. In this work the samples were manufactured using the 3D printing techniques of selective laser sintering (SLS) and high-resolution liquid crystal display (LCD) photopolymerization. Stress–strain compression tests, experimental measurements of Poisson’s ratio, homogenization modeling, investigation of mean average and Gaussian curvatures in metamaterials were performed. The homogenization method showed that crystal-inspired lattices demonstrate a Poisson’s ratio approximately ∼ 20 % lower than that of their TPMS analogs, sometimes even more, up to ∼ 3 times lower. Despite this reduction in Poisson’s ratio, the mechanical properties remained comparable to those of TPMS lattices. Crystal-inspired samples exhibit enhanced damage tolerance, showing significantly greater resistance to cracking and a delayed onset of destructive failure compared to their TPMS counterparts. The reduced Poisson’s ratio of crystal-inspired metamaterials was explained by the peculiar distribution of mean and Gaussian curvature in such metamaterials. Since Poisson’s ratio is an important mechanical parameter, this explains the improved mechanical performance of crystal-inspired lattices. This observation shows the potential of crystal-inspired topologies. The metamaterials investigated demonstrate broad applicability in commercial sectors demanding high energy absorption, isotropic properties, and load-bearing capacity, as well as in structural and mechanical engineering where consistent properties across all directions are crucial, such as in building, bridge, and vehicle construction.