  Molecular dynamics (MD) simulations with Adaptive Intermolecular Reactive
Empirical Bond Order (AIREBO) force fields were conducted to determine the
transversely isotropic elastic properties of carbon nanotubes (CNTs) containing
vacancies. This is achieved by imposing axial extension, twist, in-plane
biaxial tension and in-plane shear to the defective CNTs. The effects of
vacancy concentrations, their position and the diameter of armchair CNTs were
taken into consideration. It is revealed that the position of vacancies along
the length of CNTs is the main influencing factor which governs the change in
the properties of CNTs, especially for vacancy concentration of 1%. The current
fundamental study highlights the important role played by vacancy defected CNTs
in determining their mechanical behaviors as reinforcements in multifunctional
nanocomposites.
