Important issues in a molecular dynamics simulation for characterising the mechanical properties of carbon nanotubes

Abstract

This paper discusses several important issues in a molecular dynamics simulation for analysing carbon nanotubes and their mechanical properties. In particular, the paper addresses the problems in selecting appropriate inter-atomic potentials, number of thermostat atoms, thermostat techniques, time and displacement steps and number of relaxation steps to reach the dynamic equilibrium. Based on these, the structural changes of armchair and zigzag nanotubes and their mechanical properties are investigated. The Young's modulus and Poisson's ratio of the armchair tube are 3.96 and 0.15 TPa, respectively, and those of the zigzag tube are 4.88 and 0.19 TPa, respectively. The best simulation technique identified in this study predicts that the ultimate tensile strain of a carbon nanotube is around 40% before atomic bond breakage.