Predictions of temperature-dependent material properties and auxeticity of graphene platelets

In current engineering applications, there is a lack of a complete set of material properties for graphene platelets (GPLs). In this paper, we predict the material properties of GPLs through atomistic structural mechanics and molecular dynamics (MD) simulations. A novel spring beam-based finite element model is designed and implemented for the analysis of material properties. Numerical results of the atomistic structural mechanics model are compared with those of the MD model. In the present proposed model, the interlayer distance of GPL is varied as the number of layer increases, and the numerical results show that the varying of interlayer distance has a significant influence on the Young's moduli E₁₁ and E₂₂, and shear modulus G₁₂ of GPLs under AIREBO potential. The simulation results reveal that the material properties of GPLs are slightly anisotropic and in most cases GPLs have auxetic properties. The temperature-dependent material properties, including Young's moduli, shear modulus and thermal expansion coefficients of GPLs with in-plane positive and negative Poisson's ratios are obtained for the first time.