Nonlinear mechanical behaviour of γ-graphyne through an atomistic finite element model

A non-linear finite element model for the simulation of the mechanical in-plane behaviour of gamma-graphyne is presented in this paper. Different types of bonds (Single C-C, Aromatic C=C, Triple are simulated by means of non-linear springs, which accurately take into account the different behaviour of interatomic forces in tension and compression at 0 K temperature. Then, the finite element model is used to conduct six tests (two uniaxial tension-compression tests, one biaxial tension-compression test, two uniaxial shear tests, one biaxial shear test) to evaluate the non-linear mechanical behaviour of gamma-graphyne. After that, a set of linear elastic properties (Young's modulus, Poisson's ratio, shear modulus, bulk modulus) and non-linear elastic properties (limit of proportionality stress and strain, ultimate stress and strain) is reported and compared with values reported in the literature (mostly linear elastic properties). This validation shows that the developed finite element model is able to predict accurately the linear and non-linear mechanical properties of gamma-graphyne (i.e. stiffness and strength). Additionally, some remarks are drawn regarding the anisotropy of gamma-graphyne and its distinct behaviour under tension and compression. (C) 2017 Elsevier B.V. All rights reserved.