Study on elastic modulous of carbon nanotubes using molecular dynamic simulations

Abstract

CNTs are cylindrical nanostructures having a range of potential applications in nanotechnology. Therefore, an accurate study of mechanical behavior of CNTs is vital. Elastic modulus is an important parameter which is used to predict the mechanical performance of CNT. Molecular Dynamics (MD) is a widely used numerical method which provides a proper balance between accuracy and efficiency in studying nano systems and estimating mechanical properties of CNTs. This study has focused on studying the effect of potential function and Length/Diameter ratio of CNT during the prediction of elastic modulus using MD simulations. Study was done by MD simulations of CNTs subject to tensile test using LAMMPS (large-scale atomic molecular massively parallel simulator) molecular simulator. Most commonly used potential functions; REBO (Reactive Empirical Bond Order) and AIREBO (Adaptive Intermolecular Reactive Empirical Bond Order) were used on studying their influence on CNTs of Zigzag and Armchair chiralities. Results revealed that effect of aspect ratio can be eliminated by using the value CNT of Length/Diameter more than 12. Also, irrespective of the chirality, the surface elastic modulus calculated using the AIREBO potential function was higher than that of REBO potential. Both predict higher elastic modulus value for Zigzag CNTs than Armchair CNTs with negligible variation of values with the increase of CNT diameter.