Aspect ratio dependent buckling mode transition in single-walled carbon nanotubes under compression

Using molecular dynamics simulations, we study axial compressive behavior of single-walled carbon nanotubes (SWCNTs) with a wide range of aspect ratios (length to diameter ratio). It is shown that the difference in aspect ratio leads to distinct buckling modes in SWCNTs. Small-aspect-ratio SWCNTs primarily exhibit shell buckling; they switch to a column buckling mode with increasing aspect ratio. Further compression of the already column buckled large-aspect-ratio SWCNTs results in a shell buckling. This shell buckling mode is distinct from that of small-aspect-ratio SWCNTs in that it originates from the column buckling induced bending deformation. The transition strain from column buckling to shell buckling of large-aspect-ratio SWCNTs is predicted using an analytical expression. The underlying mechanism is discussed by analyzing the variation of C-C bond lengths and angles. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3569616]