Effects of vacancy defect on the tensile behavior of graphene

Graphene is the strongest material but its performance is significantly weakened by vacancy defects. We use molecular dynamics simulations to investigate the tensile behavior of a graphene which contains a single vacancy defect. Our results suggest that because of the single vacancy, the fracture strength of graphene losses about 17.7%. The stress concentration around the vacancy defect leads to the destruction of nearby six-member rings structure, which forms the initial crack. The propagation direction of this crack in defective graphene is at an angle of 60° to the tensile direction initially, but then becomes perpendicular to the tensile direction.