Nanoindentation Models of Monolayer Graphene and Graphyne under Point Load Pattern Studied by Molecular Dynamics **Supported by the National Natural Science Foundation of China under Grant No 11274262, the Natural Science Foundation of Hunan Province under Grand No 14JJ2046, and the Program for Changjiang Scholars and Innovative Research Team in Universities under Grant No IRT13093.

Abstract

Molecular dynamics simulations are performed to study the nanoindentation models of monolayer suspended graphene and graphyne. Fullerenes are selected as indenters. Our results show that Young's modulus of monolayer-thick graphyne is almost half of that of graphene, which is estimated to be 0.50 TPa. The mechanical properties of graphene and graphyne are different in the presence of strain. A pre-tension has an important effect on the mechanical properties of a membrane. Both the pre-tension and Young's modulus plots demonstrate index behavior. The toughness of graphyne is stronger than that of graphene due to Young's modulus magnitude. Young's moduli of graphene and graphyne are almost independent of the size ratio of indenter to membrane.