Influence of defects on the static and dynamic buckling behavior of single-wall carbon nanotubes via molecular dynamics method

Abstract

Carbon nanotubes (CNTs) exhibit often various defects during the preparation process. Thus, a detailed understanding of the impact of defects on the mechanical properties of CNTs is essential for the design of both CNTs devices and composites. Along these lines, in this work, the effects of two common defects (vacancy and Stone-Wales) on static buckling and dynamic vibration properties of single-walled carbon nanotubes (SWCNTs) are investigated. Firstly, the formation energies of single vacancy defects and Stone-Wales (S-W) defects are studied by molecular dynamics (MD), while the impact of these two defects on the compression performance and natural frequency properties of SWCNTs are explored. Secondly, the axial vibration properties of SWCNTs are studied by using the nonlocal elastic theory and the influence of defects on the dynamic axial displacement of SWCNTs under different aspect ratio is also studied. Moreover, through the change of axial displacement, the change trend of SWCNTs natural frequency with the change of aspect ratio is predicted. The results show that SWCNTs with larger aspect ratios are more prone to defects and its natural frequency will decreases. The study also found that the existence of defects will reduce the buckling properties and vibration characteristics of SWCNTs, and the impact of the S-W defect on the axial mechanical properties of SWCNTs are greater than that of the vacancy defect.