The effect of vacancy defects and temperature on fundamental frequency of single walled carbon nanotubes

Carbon Nanotubes (CNTs) are new materials with extraordinary properties. To use them, it is necessary to predict and model their behavior under different situations. Any defect in the manufactured CNTs affects its sensing performance and also influences its dynamic behavior. In this paper, the effect of vacancy defects on the fundamental frequency of Single Walled Carbon Nanotubes (SWCNTs) is investigated. The relation between the aspect ratio (L/d) and the fundamental frequency of undefected (pure) and defected CNT with removing one carbon atom of CNTs and the effect of number of defects (i.e. removing more carbon atoms) are studied. Moreover, the influence of varying the position of one defect in the length of the SWCNT, for a specific aspect ratio, on the fundamental frequency is studied. In addition, the effect of temperature and vacancy defects on the fundamental frequency of a clamped CNT is examined. The main concept used in modeling CNTs is based on structural mechanic. The simulations are carried out for two types of zigzag CNT (7, 0) and armchair CNT (4, 4). The simulation results indicate that the existence of vacancy defects mostly affects the fundamental frequency of CNTs. With increasing the number of defects, the fundamental frequency of CNTs will decrease. Furthermore, by increasing the environmental temperature, the fundamental frequency of CNTs decreases. And finally, the effect of both the increasing temperature and existence of vacancy defects decreases the fundamental frequency of CNTs.