According to the nonlinearity of bearing stiffness in aero-engine

a computational method for imbalance response of multi-degree-of-freedom rotor system was developed based on the harmonic balance method. Numerical simulation of imbalance response of the double-disc rotor system with nonlinear bearing was carried out. Important laws and key parameters having impact on the response of nonlinear rotor system were founded. Result shows that the nonlinear characteristics of imbalance response are closely related with the vibration mode; the peak frequency and peak amplitude of rotor increases with the growing bearing stiffness nonlinearity and the imbalance; the third order and fifth order response occurs with nonlinear bearing.