Mechanical behavior of carbon nanotube and graphene junction as a building block for 3D carbon nanostructures

The incorporation of defects in junction area of 1D and 2D carbon nanostructures has a major impact on properties of their 3D structures. In the present study, molecular dynamics simulation is utilized to examine the mechanical behavior of graphene sheet (GS) in carbon nanotube (CNT)-GS junctions. The tensile load was applied along the GS in connection with CNTs of different chiralities. The adaptive intermolecular reactive empirical bond order potential was chosen to model C-C interactions. It provided a reliable model for CNT, GS and their junctions. The results revealed that the connection of CNT to the GS with a hole could improve the mechanical properties of defective GS, which appeared to be independent of CNT type. It was found that the high strength C-C bonds postpone the crack propagation and motivates new crack nucleation. When a hole or CNT placed on the GS, it caused stress concentration, exactly along a line on its side. The lower mechanical properties were consequently associated with crack nucleation and propagation on both sides in a way that cracks encountered each other during the failure; while, the cracks in pristine GS propagate parallel to each other and could not encounter each other.