Atomistic and continuum modeling of 3D graphene honeycombs under uniaxial in-plane compression

Abstract

Using large-scale molecular dynamics (MD) simulations in conjunction with continuum modeling, the deformation behaviors of three-dimensional (3D) graphene honeycomb structures under uniaxial in-plane compression have been systematically investigated. The stress-strain responses of graphene honeycombs were found to be dependent on the loading direction, prism size and lattice orientation, but little affected by the junction type. Two critical deformation events, i.e., elastic buckling and structural collapse, were identified, with the associated local and global structural changes associated at these critical events clarified. Continuum models accounting for the effect of lattice orientation and size-dependent yielding have been developed to quantitatively predict the threshold stresses for those critical deformation events. In addition, it has been demonstrated that the overall stress-strain curve of graphene honeycomb can also be reasonably well predicted via continuum modeling, albeit deviation at large strains due to effect of junction on cell wall bending. The present study provides critical mechanistic understanding and predictive tools for optimizing and designing 3D graphene honeycombs in small-scale applications.