Dynamic modeling and vibration characteristic analysis of the inter-shaft bearing’s multiple point fault

It’s very important to obtain the vibration characteristics of multi-point composite fault of inter-shaft bearing accurately for improving the fault diagnosis accuracy of the inter-shaft bearing. Based on the nonlinear Hertz contact theory, the multi-point local defects are described by time-varying displacement excitation. A 4-DOF dynamic model of multi-point composite faults of inter-shaft bearing is established. The dynamic characteristics of multi-point faults of inner ring, outer ring and complex rings are analyzed. The fault simulation experiment platform of the inter-shaft bearing was built, and the simulation tests of the inner ring multi-point fault, the outer ring multi-point fault and the inner and outer ring composite fault of the inter-shaft bearing were carried out, and the vibration signals were collected to verify the established dynamic model. The results show that the error between the calculated fault characteristic frequency value and the experimental value is less than 1%. The distribution law of fault components in the time domain waveform and envelope spectrum of the simulation is consistent with the experimental results. The built dynamic models of multi-point faults in inner and outer rings and composite faults in Inner and outer rings are accurate and effective. © 2022 Chinese Vibration Engineering Society. All rights reserved.