Based upon the experimental realization of low-friction nanoscale bearings, carbon nanotubes (CNTs) attracted interest for designing GHz nested CNT nanomechanical oscillators. A key issue in designing such devices is the energy dissipation during the oscillatory sliding of the inner CNT. In this work, dynamical sliding of concentric double-walled CNTs of nanometer lengths and different commensurations is investigated with molecular dynamics (MD) simulations and a model potential that accounts for inter-tube corrugation. We find that the small variations in energy under inter-tube shifts and rotations, usually not accounted for in classical MD, give rise to a rich dependence of the frictional forces not only on velocity and edge, but also on the contact area and commensuration. Coupled to sliding, there is an unusual self-excited spinning motion, which is also connected to commensuration. These results advance our understanding of dynamical friction and suggest that considerations on interfacial corrugation should not be overlooked when designing CNT oscillators even when their intra-tube gap is around 3.4 Å.
|Original language||English (US)|
|Journal||Extreme Mechanics Letters|
|State||Published - Jul 2019|
Bibliographical noteFunding Information:
This work was supported by NASA’s Space Technology Research, USA Grant NNX16AE03G , and by the Institute for Ultra-Strong Composites by Computational Design, USA Grant NNX17AJ32G . Resources supporting this work were provided by the Minnesota Supercomputing Institute. We thank Leonid Zhigilei for useful discussions.
© 2019 Elsevier Ltd
- Carbon nanotubes
- Dynamical friction
- Nanomechanical oscillators