... into the nonlinear dynamics of EATs supported by FRBs, focusing on oil whirl, oil whip, and total instability caused by oil instability. The effects of inner and outer oil film clearances in FRBs, motor rotor mass, motor placement, and oil film viscosity on the synchronous vibration, sub-synchronous vibration...

... coupled together. In particular, a new phenomenon is found for the four-bearing rotor system: the pre-existing non-synchronous whirl/whip resulted from the instability of one shaft can activate the onset of oil instability of another shaft. In the theoretical simulation, this phenomenon represents...