Chirality independence in critical buckling forces of super carbon nanotubes

The elastic buckling of super carbon nanotubes (STs) under compression and bending were studied by the molecular structure mechanics method. Under compression, the elastic buckling mode of the ST is similar to that of a cantilever column. However, the bending buckling mode of ST could transform from shell wall buckling to beam buckling as the length of ST increases. Therefore, the classical Euler formula could give good prediction both to the critical compression force for ST and to the critical bending force for very long STs. A phenomenological formula for the critical bending force of ST was given in this work, which could well predict the critical bending buckling of STs and bridge over the transformation of the bending buckling mode. Two types of chirality independent phenomena were found: first, the critical compression force carried by the unit carbon nanotube inside STs is independent of the chirality of STs; second, the critical bending force of ST's is independent of the chirality of STs. (C) 2008 Elsevier Ltd. All rights reserved.