Structural matching investigation of FPCBBs and CRBs in offshore wind gearbox based on rotor dynamic model

The paper introduces a dynamic model of the bearing-rotor system covering four-point contact ball bearings (FPCBB) and cylindrical roller bearings (CRB), specifically tailored for offshore wind applications. The slice method is well addressed the non-uniform contact between the rollers and other components. The semi-flexible body element strikes an optimal balance among rotor flexibility, real-time coupling, and simultaneous solution of the bearing and rotor models. The differences between the rigid and flexible models in predicting the system behavior are compared. The effect of the bearing clearance on its dynamic performance is further investigated. The results show that the flexible model is capable of predicting stress concentrations in the CRB raceways with a stress error of 12% compared to the rigid model. The occurrence of multi-point contact state inside FPCBB is predicted by the flexible model. The CRB clearance has a more significant effect on the system dynamic performance. And the wider the CRB clearance, the more pronounced the sliding inside the raceway of the right CRB, which can reach an alarming velocity of 18 m s- 1. These findings offer valuable insights for the modeling and performance optimization of bearing-rotor systems in offshore wind turbine gearboxes, ensuring enhanced reliability in demanding ocean environments.