The Effect of Atom Vacancy Defect on the Vibrational Behavior of Single-Walled Carbon Nanotubes: A Structural Mechanics Approach

Abstract

An atomistic structural mechanics method, which is based on the exclusive use of spring elements, is developed in order to study the effect of imperfections due to atom vacancy on the vibrational characteristics of single-walled carbon nanotubes (SWCNTs). The developed elements simulate the relative translations and rotations between atoms as well as the mass of the atoms. In this way, molecular mechanics theory can be applied directly because the atomic bonds are modeled by using exclusively physical variables such as bond stretching. The method is validated for its predictability comparing with vibration results found in the open literature for pristine nanotubes. Then, it is used for the vibration analysis of defective nanotubes. Imperfections such as one-atom vacancy, two-atom vacancy, and one carbon hexagonal cell vacancy are investigated. Their effect on vibrational behavior is explored for different defect positions, nanotube diameters, and support conditions. According to the obtained results, the fundamental frequency is decreased as the size of imperfection increases, and the percentage reduction in fundamental frequency due to the atomic vacancy defect is more affected for a single-clamped SWCNT than for a double-clamped one.

Influence of Various Defect Parameters on the Vibration Characteristics of a Single-Walled Carbon Nanotube

“…Finite element approach has been adopted by many researchers to study the fundamental frequencies of carbon nanotubes with randomly distributed defects of different quantities [17,18]. Atomistic structural mechanics method has also been used to study the effect of atom vacancy on the vibrational characteristics of the SWCNTs where the fundamental frequency was found to decrease with the increase in size of the vacancy [19].…”

Vibration of carbon nanotubes with defects: order reduction methods

“…Prior attempts have been made, notably by Chen et al [9] and Georgantzinos et al [10], to account for the impact of defects on the vibration of CNTs using numerical methods. These studies report changes in the natural frequencies of CNTs due to the presence of defects but do not consider changes in the corresponding mode shapes.…”