An investigation into the mechanical behavior of single-walled carbon nanotubes under uniaxial tension using molecular statics and molecular dynamics simulations

Abstract

This study performs a series of Molecular Dynamics (MD) and Molec- ular Statics (MS) simulations to investigate the mechanical properties of single- walled carbon nanotubes (SWCNTs) under a uniaxial tensile strain. The simula- tions focus specifically on the effects of the nanotube helicity, the nanotube diame- ter and the percentage of vacancy defects on the bond length, bond angle and tensile strength of zigzag and armchair SWCNTs. In this study, a good agreement is ob- served between the MD and MS simulation results for the stress-strain response of the SWCNTs in both the elastic and the plastic deformation regimes. The MS simulations reveal that in the plastic deformation regime, the tensile strength of the armchair and zigzag SWCNTs increases with an increasing wrapping angle. In addition, it is shown that the tensile strength reduces significantly at larger val- ues of the nanotube diameter. Moreover, it is observed that the tensile strength of both SWCNTs reduces as the percentage of defects within the nanotube structure increases. Finally, it is found that the results obtained from the molecular statics method are relatively insensitive to instabilities in the atomic structure, particularly in the absence of thermal fluctuations, and are in good agreement with the predic- tions obtained from the molecular dynamics method.