Effect of wall thickness on the mechanical properties of single-walled carbon nanotubes

A three-dimensional finite element (FE) model for the prediction of mechanical properties of defect-free carbon nanotubes (CNTs) is developed by incorporating the modified Morse potential energy with an analytical molecular structural model. The model is capable of predicting Young’s and shear modulus of elasticity and Poisson’s ratios of Armchair and Zigzag single walled-carbon nanotubes (SWCNTs) under tension and torsion loading conditions. Additionally, the effects of wall thickness on mechanical properties of SWCNTs were studied in details. The results show that with increasing tube diameter, the elastic and shear modulus of both Armchair and Zigzag CNTs increase monotonically and approach the elastic properties of Graphene, but the variation trend of Poisson’s ratio is reverse, also the Young’s modulus values are inversely proportional to the wall thickness and if the value of 0.066nm is used for the wall thickness, the Young’s modulus is estimated about 1TPa which agree very well with the corresponding theoretical and experimental measurements.