Investigation on characteristics of vibration interaction between supporting bearings in rotor-bearing system

In the rotor-bearing system (RBS), the vibration interaction between the supporting bearings can lead to a vibration response on a healthy bearing that resembles that of a faulty supporting bearing, resulting in a false positive fault diagnosis. To address this issue, a dynamic model of the RBS was developed that took into account the effects of vibration interactions and was verified through experimentation. The vibration characteristics of supporting bearings is analyzed under typical types of vibration interaction. The amplitudes of characteristic frequencies for true and false positives of faults are also discussed. Based on the bearing vibration interaction characteristics in RBS, a fault diagnosis criterion was established to eliminate the impact of the amplitude of characteristic frequency and identify the false positive of fault. The criterion was applied to experimental data and found to be effective.