The Young's modulus of triangle-like three-dimensional graphene under uniaxial tension: Finite element method and theoretical model

Two-dimensional (2D) graphene possesses a variety of excellent properties. It is worth using 2D graphene as building block to construct novel three-dimensional (3D) graphene which “inherits” superb performance of 2D graphene. Combining theoretical calculations and finite element method (FEM) based on molecular structural mechanics, the effects of graphene sidewall width, junction structure, in-plane domain size and in-plane overall shape on the elastic properties of zigzag honeycomb 3D graphene and three types of triangle-like 3D graphene are investigated, and the analytical expressions for Young's modulus of triangle-like 3D graphene are derived. The results of FEM are consistent with those of theoretical method. It is found that as graphene sidewall width increases, in-plane/out-of-plane Young's moduli of the above-mentioned 3D graphene first decrease and then tend to stabilize. For the armchair and zigzag triangle-like 3D graphene (sidewall width remains unchanged) with rectangular in-plane overall shape, the Young's modulus will vary with in-plane domain size. These results show that the elastic properties of 3D graphene are strongly dependent on structural size. In addition, junction structure has little influence on the elastic properties of 3D graphene.