Size-dependent elastic mechanical properties of γ-graphyne structures: A comprehensive finite element investigation

The size-dependent elastic mechanical properties of various γ-graphyne structures as graphyne, graphdiyne, graphyne-3, and graphyne−4 are studied in this work. The interatomic interactions between the carbon atoms in a nanostructure are simulated combining the molecular mechanics theory with appropriate spring-like finite elements. Specifically, the bond tension and bond angle bending interactions are simulated with suitable translational spring elements concerning three types of covalent bonds: single, aromatic, and triple. Considering the ideal geometry of every graphyne structure and regarding different nanostructure sizes, several finite element models are employed. Applying suitable boundary conditions to the models, the size-dependent mechanical properties as Young's and shear moduli, as well as Poisson's ratio of every nanostructure are finally calculated in each direction. Fitting the finite element analysis results, new empirical-analytical equations are derived for the prediction of graphyne structures elastic constants. The comparison of the obtained results with the results found in the open literature, where it is possible, establishes the reasonable accuracy of the proposed approach.