Effect of vacancy defects on the fundamental frequency of carbon nanotubes

Carbon nanotubes are widely used in the design of nanosensors and actuators. Any defect in the manufactured nanotube plays an important role in the natural frequencies of these structures. In this paper, the effect of vacancy defects on the vibration of carbon nanotubes is investigated by using an atomistic modeling technique, called the molecular structural mechanics method. Vibration analysis is performed for armchair and zigzag nanotubes with cantilever boundary condition. The shift of the principal frequency of the nanotube with vacancy defect at different locations on the length is plotted. The results indicate that the frequency of the defective nanotube can be larger or smaller or equal to the frequency of perfect one. The results also show that with the reduction in the tube length, the variations of principal frequency are enhanced. However, the frequency variation is insensitive to the nanotube diameter. As the number of vacancy defects increases, shift in the natural frequency also increases as expected.