Elastic properties of crystals of single-walled carbon nanotubes

The elastic constants, Youngʹs and bulk moduli, and Poisson ratio of triangular close-packed crystal lattices of single-walled carbon nanotubes are calculated for various tube types using analytical expressions. Some of these quantities exhibit up to three different regimes of behavior which are due to the interplay of the intertube van der Waals forces and the elastic forces in the tubes. These regimes are most prominent in the case of the bulk modulus which has a maximal value of 38 GPa at tube radius R≈6 Å and decreases for larger radii.