Non-synchronous Vibration due to Internal Radial Clearance in Roller Bearings

Non-synchronous vibration is a common phenomenon in rotor-bearing systems which causes cabin comfort issues in mid size business jets. In rotating systems, the most significant source of non-synchronous vibration is the nonlinear contact in supporting bearings which is affected by internal radial clearance, contact materials, roller numbers and mass imbalance, etc.;In this study, a Jeffcott rotor-bearing system is modeled using the finite element method. For solutions of the system’s governing equations, both the time-marching technique and harmonic balance method are used. Moreover, a modal reduction technique is applied to save the computations. For bearing contacts, three treatment approaches are adopted: the Hertz theory, the Lagrange multipliers technique and the forcing functions. Finally, the non-synchronous vibration is investigated with respect to the bearing’s parameters, and the internal radial clearance is proven to play the most significant role in controlling the non-synchronous vibration.