Sustained smooth dynamics in short-sleeved nanobearings based on double-walled carbon nanotubes.

We carry out a molecular dynamics study of nanobearings based on double-walled carbon nanotubes with a short rotating outer tube. A (4, 4)/(9, 9) bearing configuration shows peculiar stabilization of rotational motion at certain values of angular velocities. The observed trend is found at those values of initial angular velocities (in the current context, 0.8-1.5 rad ps(-1)) which denote a transitional regime between nearly frictionless operation at low initial angular speeds and decaying performance at high initial angular velocities. With the use of detailed 'principal components analysis', we find that the energy dissipation occurs mainly due to the excitation of wavy modes in the inner tube of the bearing. It is also proposed that wavy deformation is facilitated by the actuation of axial translation of the outer tube, which acts as an energy channelling mode. Hence, we find that the absence of dissipative wavy modes results in sustained smooth rotational dynamics of the nanobearing at low temperature.