An efficient molecular mechanics model for the torsional buckling analysis of multi-walled silicon carbide nanotubes

Department of Mechanical Engineering, University of Guilan, P.O. Box 3756, Rasht, Iran

^a e-mail: hessam@gmail.com

Received: 2 October 2014
Revised: 1 March 2015
Accepted: 30 March 2015
Published online: 21 April 2015

Abstract

In this article, by using the molecular mechanics approach, the torsional buckling behavior of chiral multi-walled silicon carbide nanotubes (MWSiCNTs) is analytically investigated. The force constants of the molecular mechanics are theoretically obtained through establishing a linkage between the molecular mechanics and the quantum mechanics. First, surface Young’s modulus, Poisson’s ratio, flexural rigidity and atomic structure of silicon carbide (SiC) sheets are calculated according to the density functional theory (DFT) within the framework of the generalized gradient approximation and using the exchange correlation of Perdew-Burke-Ernzerhof. A closed-form expression is proposed by which through knowing the chirality of an MWSiCNT, the critical buckling shear strain can be quickly and accurately evaluated. The critical buckling shear strain is obtained for various types of chirality and different number of walls. It is concluded that with the increase of number of walls, the value of critical buckling shear strain decreases and nanotubes tend to be more unstable. Also, among all the chiral nanotubes, the one with chiral angle of (n, n/2) has the minimum value of critical buckling shear strain.