TPMS metamaterial structures based on shape memory polymers: Mechanical, thermal and thermomechanical assessment

Abstract

Triply periodic minimal surfaces (TPMS) are a type of metamaterial that get their unusual properties from the topology of microstructure elements, but they provide non-controllable properties. Utilizing shape memory polymer as a base material, it is possible to control the properties of these structures and create significant and reversible changes in the stiffness, geometry, and performance of metamaterials which could be applicable in many application fields. In this work, the thermal, mechanical, and shape memory behavior of 8 SMP-based TPMS structures has been studied in a wide range of the solid phase volume fractions (i.e., 35–65%). In the thermomechanical analysis, we consider the shape recovery%, the force recovery%, and the shape fixity% as the shape memory properties. For this purpose, the structures were simulated using thermo-visco-hyperelastic constitutive equations. Also, the temperature rate and elastic modulus are considered as the representative thermal and mechanical properties, respectively. Results of this study indicate that the best shape memory and mechanical behaviors belong to the Primitive structure at all different Volume fractions. And the best overall performance for different 8 TPMS structures including the best thermal, mechanical, and thermomechanical behavior accrues at VF = 40% and is sorted as FKS > FRD > Diamond > Diamond-type 2 > Gyroid > IWP > Primitive > Neovious.