Research on the dynamic mechanism of the gear system with local crack and spalling failure

This study focuses on the dynamic and vibration characteristics of a four-degree of freedom gear system with local defects to explore the failure mechanism. The dynamic models of the gear system with tooth crack and spalling failure are respectively established to investigate the effect of the failures on mesh stiffness and dynamic response by numerical simulation. The differences and comparisons between the vibration signals with the tooth crack and spalling failure are discussed by using time history, phase contrail, Poincaré section, spectrum analysis and fractal dimension, which shows the different dynamic characteristics between the tooth crack and spalling failure. An experimental gearbox with tooth crack and spalling failure was designed and experiments was carried out to determine the dynamic characteristics of the faulty vibration signals. The results obtained herein show good agreement qualitatively with the theoretical analysis, which provides a theoretical basis for the fault diagnosis of gearboxes.

► The gear dynamic model with local crack and spalling failure is established.
► The dynamic mechanism of the gear with failures is analyzed.
► The gear system is diagnosed by fractal method.
► The theory and experimental results show the different dynamic mechanism caused by the different faulty signals.