Mechanics of Boron Nitride Nanotubes: a Continuum Theory Based on the Interatomic Potential

Boron nitride nanotubes display unique properties and have many potential applications. An atomistic-based continuum theory is developed for boron nitride nanotubes. The continuum constitutive model for boron nitride nanotubes is obtained directly from the interatomic potential for boron and nitrogen. Such an approach involves no additional fitting parameters beyond those introduced in the interatomic potential. The atomistic-based continuum theory is then applied to study the elastic modulus, stress-strain curve and nonlinear bifurcation in boron nitride nanotubes. An analytic approach is then established to determine the tensile and bending rigidity of a hexagonal boron nitride (h-BN) monolayer and single- and multi-wall boron nitride nanotubes directly from the interatomic potential. Such an approach enables one to bypass atomistic simulations and to give the tensile and bending rigidity in terms of the parameters in the potential. The thickness of h-BN monolayer is also discussed. A hybrid atomistic/continuum model based on the interatomic potential for boron nitride is also developed to study the Stone-Wales transformation in boron nitride nanotubes under tension.