Molecular dynamics simulations of the mechanical properties of two new types of graphyne nanotubes: α-graphyne and α2-graphyne nanotubes

In this paper, molecular dynamics simulations are applied to study the mechanical properties of two types of graphyne nanotubes; including alpha-graphyne and alpha 2-graphyne nanotubes. The effects of the geometrical properties of the nanotubes on the stress-train curve, Young's modulus, fracture strain and maximum stress are studied. It is observed that Young's modulus of the alpha-graphyne nanotubes are significantly smaller than Young's modulus of the alpha 2-graphyne nanotubes with the same geometrical parameters. Similarly, the maximum stress tolerated by the armchair alpha 2-graphyne nanotubes are larger than the armchair alpha-graphyne nanotubes. However, alpha-graphyne nanotubes tolerate larger fracture strains than the alpha 2-graphyne nanotubes. It is shown that increasing the nanotube diameter leads to increase in Young's modulus of the alpha-graphyne nanotubes and alpha 2-graphyne nanotubes. However, increasing the nanotube lengths has an inverse effect on Young's modulus of the considered nanostructures.