Effects on Pre-Applied Compression on Tensile-Strength of 3-Dimensional Graphene Foams

3D graphene foams (GrFs) are widely used in a variety of structural and functional applications because of their superior mechanical properties provided by the combination of porous structures and strong graphene sheets. A large number of simulations and experiments have been conducted in order to study the mechanical properties of GrFs using compression and tensile tests. In recent experiments it was shown that the mechanical strength of GrFs increases after they undergo pre-applied compression processes. In this study, we investigate the mechanical properties and deformation mechanisms of GrFs in the tensile test followed by compression, using molecular dynamics simulation. A 3D bonded graphene foam system is created, which consists of randomly-oriented 2D coarse-grained mesoscopic graphene flakes connected via permanently-bonded crosslinks and van-der-Waals interactions among each other. The simulation results reproduce the experimentally-observed behaviors that the tensile strength of GrF increases with pre-applied compression. The fundamental mechanisms and optimal conditions are presented through the analysis of the simulation outcomes.