Chirality and scale effects on mechanical buckling properties of zigzag double-walled carbon nanotubes

In this paper, the mechanical buckling properties of a zigzag double-walled carbon nanotube (DWCNT) with both chirality and small scale effects are studied. Based on the nonlocal continuum theory and the Timoshenko beam model, the governing equations are derived and the critical buckling loads under axial compression are obtained. The DWCNTs are considered as two nanotube shells coupled through the van der Waals interaction between them. The equivalent Young's modulus and shear modulus for zigzag DWCNT are derived using an energy-equivalent model. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed. These findings are important in mechanical design considerations of devices that use carbon nanotubes. (C) 2013 Elsevier Ltd. All rights reserved.