Free Vibrations of Carbon Nanotubes with Defects

In the paper the eigenfrequencies of pristine and defective single-walled carbon nanotubes are investigated. The defects are in the form of point vacancies. The axial vibrations of structures are studied only. A special attention is focused on the effects of material and geometrical properties of nanostructures on the results. Three different models are considered: the Euler beam model, a continuous specially orthotropic model and a 3D nonlinear finite element model consistent with molecular mechanics formulations. The results demonstrate that the Euler beam model overestimates the values of natural frequencies.