SINGLE-WALLED NANOTUBES AS KIRCHHOFF ELASTICAS

Abstract

Under compressive loads, single-walled carbon nanotubes (SWNTs) are known to behave like cylindrical shells at small aspect ratios and undergo a shell to column transition at somewhat larger aspect ratios. At even larger aspect ratios SWNTs are capable of undergoing large elastic deformations without suffering localized plastic kinks. In this work, we show that a very long SWNT can be modeled as a Kirchhoff elastica with a small initial twist. The elastic properties of the nanotubes, required to model them as elastica, are obtained from MD simulations on short SWNTs. The total twist on particular straight nanotube depends on its length, diameter and chirality and though small, affects the post buckling deformation of long nanotubes significantly. The modeling of a long SWNT as a twisted elastica may be effectively used to search for their possible folded and coiled equilibrium configurations under various ambient conditions.