The tensile behavior of single-walled nanotubes containing two defects (vacancy or Stone-Wales) positioned next to each other was simulated in order to investigate the influence of the spatial arrangement of defects upon the mechanical properties. The simulations were performed using classical molecular dynamics at the atomic scale. Two neighboring vacancy defects reduced the failure strength by as much as 46%, and the failure strain by as much as 80%; as compared with those of pristine single-walled carbon nanotubes. Two neighboring Stone-Wales defects reduced them by as much as 34 and 70%, respectively. Single-walled carbon nanotubes containing two defects in the loading (axial) direction exhibited a higher failure strength than did single-walled carbon nanotubes with defects perpendicular to the loading direction. For both types of defect, the closer the defects, the weaker were the single-walled nanotubes. The defect arrangement in single-walled carbon nanotube structures was concluded to be one of the key factors determining the mechanical properties, as well as the population of defects.

The Effect of Two Neighboring Defects on the Mechanical Properties of Carbon Nanotubes. K.Tunvir, A.Kim, S.H.Nahm: Nanotechnology, 2008, 19[6], 065703