Mechanical response of graphene with nanopore under nanoindentation via molecular dynamics simulations

Abstract

We investigated structural evolution and dynamic responses of graphene sheet with one rectangular nanopore under nanoindentation by using molecular dynamics simulations. The effects of dimension and position of the pore are analyzed in terms of fracture characteristics, loading force-displacement relationship and stress distribution. We find that the fracture behavior and the stress distribution close to the pore depend on the size and position of the pore. When the long edges of the pore is placed along the radial direction, the increase of its size leads to cracking formation near the short edges. However, the loading force becomes lower for the pore with small size of the long edges. If making the direction of the long edges normal to the radical direction, different fracture behaviors, such as cracking formation, are identified, and the maximum indentation depth reduces with increasing the size of the long edges. The pore position also influences the mechanical responses. In particular, the central pore shows much lower loading force at deformation limit. Further, to understand the physical mechanisms of the fracture behaviors we evaluate the distribution of different stress components.