Peridynamic Simulation of Fracture in Polycrystalline Graphene

Abstract

Defect-free graphene is believed to be the strongest material. However, the effective strength of engineering used large-area graphene in which defects are inevitable is actually determined by the fracture toughness, rather than the intrinsic strength that governs the breakage of atomic bonds in perfect graphene. Due to the limitations of commonly adopted experiments, conventional continuum mechanics–based methods and fully atomistic simulations, fracture of polycrystalline graphene under uniaxial tensile load is explored by performing peridynamic (PD) simulations in this paper. The fracture strength, the fracture strain, and the fracture toughness of polycrystalline graphene, as well as the grain size effect and the temperature effect on such quantities, are studied in this work. The results show that the fracture strength of polycrystalline graphene and the grain size follows an inverse pseudo Hall–Petch relation. The fracture strain and the fracture toughness of polycrystalline graphene decrease with a decrease in the grain size. Increasing temperature can also weaken the fracture properties of graphene. The results can provide guidelines for the applications of polycrystalline graphene in nano devices. This study also expands the application of peridynamics and presents a new way to study the fracture of graphene.