Comparative consideration of axial stability of single- and double-walled carbon nanotube and its inner and outer tubes

The variations of critical axial forces for the inner and outer tubes of the double-walled carbon nanotube (DWCNT) in different buckling modes are studied in this paper. The effects of growth in the radius, length, and aspect ratio (length/radius) on the stability of a DWCNT and its inner and outer tubes are also considered, while the effects of the surrounding elastic medium on the outer tube and the van der Waals forces between two adjacent tubes are taken into account. Comparison between the DWCNT as a whole, its outer tube, inner tube, and single-walled carbon nanotube (SWCNT) indicates that the critical axial force of the inner tube of a DWCNT is almost two times more than the critical axial force of a SWCNT, showing the positive effect of the van der Waals interaction on the inner tube, DWCNT surrounded by an elastic medium has greater axial stability than DWCNT, without the surrounding elastic medium. This study demonstrates that the critical axial force of DWCNT is larger than for SWCNT, and it rises as the radius and aspect ratio increase.