The effect of Stone-Wales defects due to rotation of a pair of neighboring atoms on the equilibrium structure, and the mechanical properties of single-wall carbon nanotubes in axial stretching and twisting was considered. The position of carbon atoms in a test section consisting of a number of repeated units hosting a solitary Stone-Wales defect was computed by minimizing the Tersoff-Brenner potential. The energy invested in the defect was found to decrease as the radius of the nanotube became smaller. Numerical computations for nanotubes with zig-zag and armchair chiralities showed that inclined, axial and circumferential defect orientations had a strong influence on the mechanical response in axial stretching and twisting. Stretching could cause the defect energy to become negative; revealing the possibility of spontaneous defect formation leading to failure. In some cases, stretching could eliminate the defect and purify the nanotube. When the tube was twisted around its axis, a neck developed at the location of the defect, signaling possible disintegration.

Effect of the Stone-Wales Defect on the Structure and Mechanical Properties of Single-Wall Carbon Nanotubes in Axial Stretch and Twist. C.Pozrikidis: Archive of Applied Mechanics, 2009, 79[2], 113-23