Coupling effect of van der Waals, centrifugal, and frictional forces on a GHz rotation-translation nano-convertor

A nano rotation-translation convertor with a deformable rotor is presented, and the dynamic responses of the system are investigated considering the coupling among the van der Waals (vdW), centrifugal and frictional forces. When an input rotational frequency (ω) is applied at one end of the rotor, the other end exhibits a translational motion, which is an output of the system and depends on both the geometry of the system and the forces applied on the deformable part (DP) of the rotor. When centrifugal force is stronger than vdW force, the DP deforms by accompanying the translation of the rotor. It is found that the translational displacement is stable and controllable on the condition that ω is in an interval. If ω exceeds an allowable value, the rotor exhibits unstable eccentric rotation. The system may collapse with the rotor escaping from the stators due to the strong centrifugal force in eccentric rotation. In a practical design, the interval of ω can be found for a system with controllable output translation.