In order to reveal the vibration characteristics of fault rotor systems caused by the bearing misalignment

the expression of the rotor deflection displacement under the bearing misalignment was derived through the coordinate transformation relation. On this basis

the dynamic model of the double disk rotor system with the coupled bearing misalignment-rub-impact fault

considering the influence of external excitation including the rub-impact force and the oil film force was established. The effects of rotational speed and mass eccentricity on the dynamic response of the system were studied by means of the numerical method. The results show that the bearing misalignment fault can increase the possibility of rub-impact

worsen the shafting vibration and magnify the unsteady motion range of system. Although the addition of misalignment can delay the instability movement induced by parameter changes to a certain extent

the enlargement of amplitude is contrary to the safe operation goal for system

therefore

the necessary measures should be taken to control the bearing misalignment fault. The relevant conclusions can provide useful references for the vibration state identification and the stability analysis of rotor bearing systems.