Liquid metal-filled phase change composites with tunable stiffness: Computational modeling and experiment

Abstract

Liquid metal-filled phase change composites have promising applications as tunable stiffness components and reconfigurable structures in soft robotics, actuators, and metamaterials. At present, there is a lack of mechanistic understanding on the microscale-macroscale correlation of their mechanical behaviors. To fill this knowledge gap, we employ computational micromechanics modeling to simulate and reproduce the macroscopic mechanical behaviors of these liquid metal composites. Specifically, the liquid metal composites are simulated using representative volume elements and the particle-matrix interfaces are modeled as cohesive surfaces. The model is able to predict not only the stress-strain curves of the composites with temperature-induced phase transition but also progressive debonding between the particles and the polymer matrix. Moreover, the computational model also reproduces the debonding-induced Mullins effect of the liquid metal composites. The simulation results agree well with our experimental data by calibrating the modeling parameters carefully.