Research on Dynamic Characteristics of Two-Stage Gear System with Fatigue Cracks

The propagation of root fatigue cracks is a primary factor contributing to the fatigue failure of gear transmission systems. In view of the complex influence of cracks on the vibration characteristics of the secondary system, the current research needs to be further deepened and a dynamic model of a two-stage gear transmission system is established considering time-varying meshing stiffness. The influence of fatigue cracks on the vibration characteristics of the two-stage gear transmission system is systematically explored, and the accuracy of the model is verified through vibration experiments. It is demonstrated that fatigue cracks can significantly reduce the meshing stiffness, and the reduction increases with the crack extension. The vibration response of the system undergoes substantial changes due to fatigue cracks, especially when the crack is located in the second stage. In addition, the mutual influence between the two stages in the gear system is revealed. When entering the double-tooth meshing area from the single-tooth meshing area, the interaction between the two stages is more obvious. This study provides new insights into the complex influence of fatigue cracks on the vibration characteristics of the two-stage gear system and provides a theoretical basis for early fault diagnosis and fatigue failure prevention of gear systems.