Abstract: In a rotor-bearing system geared, there are several nonlinear factors that may cause nonlinear vibration. Considering the time-varying mesh stiffness and friction between tooth pairs, the steady state response of the system is investigated by means of the harmonic balance method. The analytical results are verified by numerical simulation. It is showed that, because of the time-varying mesh stiffness and friction between tooth pairs, even if unbalance mass does not exist in the system, vibration may occur, moreover, even if the frequency of excitation is unique, multiple frequencies may arise in the response spectra of the system.

Key words: Direct integration, Forced vibration, Friction between tooth pairs, Harmonic balance method, Time-varying mesh stiffness