Designing the nonlinear mechanical response of graphyne structures: A finite element structural mechanics approach

Abstract

Over recent decades, the exploration of various allotropes of carbon at the nanoscale has attracted a significant amount of research interest. The demand for the synthesis of novel carbon-based nanostructures has resulted in the discovery of graphynes, i.e. one-atom-thick planar crystal lattice sheets of benzene rings connected by acetylene bonds. In this study, computer modelling and simulations were applied to characterise the full tensile and elastoplastic mechanical behaviour of such structures. Using a nonlinear finite element-based structural mechanics method, which is based on Morse potential functions, several parametric studies were performed, and various illustrative size-dependent diagrams were obtained, enabling the suitable and accurate design of graphyne-based material components based on key mechanical properties such as stiffness, tensile strength, and fracture strain. The four well-known types of graphyne sheets were numerically investigated: graphyne-1, also known as graphyne; graphyne-2, also known as graphdiyne; graphyne-3; and graphyne-4. The predictions of the mechanical properties of graphene were compared with other corresponding estimations to validate the research results.