title: Mechanical properties and failure mechanisms of graphene under a central load.
abstract: By employing molecular dynamics simulations, the evolution of deformation of a monolayer graphene sheet under a central transverse loading are investigated. Dependence of mechanical responses on the symmetry (shape) of the loading domain, on the size of the graphene sheet, and on temperature, is determined. It is found that the symmetry of the loading domain plays a central role in fracture strength and strain. By increasing the size of the graphene sheet or increasing temperature, the tensile strength and fracture strain decrease. The results have demonstrated that the breaking force and breaking displacement are sensitive to both temperature and the symmetry of the loading domain. In addition, we find that the intrinsic strength of graphene under a central load is much smaller than that of graphene under a uniaxial load. By examining the deformation processes, two failure mechanisms are identified namely, brittle bond breaking and plastic relaxation. In the second mechanism, the Stone-Wales transformation occurs.
authors.affiliation: Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006 (China).
authors.forename: Shuaiwei
authors.initials: S
authors.lastname: Wang
authors.forename: Baocheng
authors.initials: B
authors.lastname: Yang
authors.forename: Shouren
authors.initials: S
authors.lastname: Zhang
authors.forename: Jinyun
authors.initials: J
authors.lastname: Yuan
authors.forename: Yubing
authors.initials: Y
authors.lastname: Si
authors.forename: Houyang
authors.initials: H
authors.lastname: Chen
keywords: failure mechanisms; graphene; mechanical properties; molecular dynamics simulations; symmetry