Torsional stiffening of carbon nanotube systems

The torsional responses of hollow and filled carbon nanotubes under a combination of tension and torsion are examined using classical molecular dynamics simulations. The critical torsional moment and shear modulus are predicted to significantly increase as a result of coupling between tension and torsion. In particular, the simulations predict that the torsional responses under this type of combined loading are beyond the linear responses of the nanotubes. Importantly, the coupling effect between tension and torsion also increases the torsional stiffness and oscillation frequency of the nanotubes.