Carbon nanotubes under a tensile load, and containing randomly distributed vacancy defects, were simulated in order to investigate the effect of the spatial distribution of defects upon the mechanical properties. A simple random unit generation method was used to allocate the defects randomly within the single-walled nanotube structure. The simulation was carried out a using classical molecular dynamics simulation at the atomic scale. A defect density of 1% reduced the failure strength, the failure strain and the Young’s modulus of carbon nanotubes by as much as 42, 65 and 2%, respectively, while a defect density of 8% lowered the properties by as much as 52, 71 and 14%, respectively. The scatter in the properties, due to the random distribution of the defects, was found to increase with increasing number of defects in the single-walled nanotubes. At a defect density of 8%, the standard deviations of the data for 20 sample simulations having various distributions normalized to the mean values calculated for the failure strength, the failure strain and the Young’s modulus were about 11, 20 and 8%, respectively. The defect arrangement in the single-walled nanotube structure was one of the key factors which determined the mechanical properties and the population of defects.

Mechanical Properties of Carbon Nanotubes with Randomly Distributed Vacancy Defects. K.Tunvir, S.H.Nahm, A.Kim, H.J.Lee: Journal of the Korean Physical Society, 2007, 51[6], 1940-7