On the Elastic Constants of Single Walled Carbon Nanotubes

M.M. Zaeri, S. Ziaei-Rad and A.R. Shahidi

Procedia Materials Science, Volume 11, November 2015, Pages 666-671

ABSTRACT

Determination of the mechanical properties of nanostructures is an essential step in their applications from macroscopic composites to nano-electro-mechanical systems. In this paper the elastic constants, i.e. the elements of the stiffness tensor, of a typical single walled carbon nanotube are predicted via molecular dynamics simulations. Several codes were developed to calculate the coordinates of the carbon atoms and the 2-atom (bond), 3-atom (angle) and 4-atom (dihedral and improper) interactions between them which represent the tensile (compressive), bending and torsional stiffness, respectively. Then, using LAMMPS package, the prepared model was simulated under constant strains in various directions. The resulting stresses were used to derive the elastic constants. Finally, the more familiar Young's and shear moduli along with Poisson's ratios were calculated. Compared to the literature, the obtained Young's modulus is well acceptable but the obtained shear modulus forms an underestimate.

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