System dynamic reliability of wind turbine gearbox under random wind load

Wind turbine gearbox has fatigue damage under random wind load to cause decrease in system reliability. Here, aiming at the problem of system reliability real-time evaluation of wind turbine gearbox, taking a 2 MW wind turbine gearbox as the study object, a dynamic model of the gearbox transmission system was established. Fatigue stresses of various components under dynamic response were statistically analyzed to generate fatigue load spectra. A stress-strength interference model considering strength degradation was established by combining nonlinear fatigue damage accumulation theory and kernel density estimation method to calculate dynamic reliabilities of various components' failure modes. Further utilizing Copula function, a system reliability model was constructed to analyze effects of common cause failures of components on reliability degradation of gearbox system. The results showed that reliabilities of planetary gear system and medium speed shaft bearings of gearbox decrease more rapidly in operation process, and reliabilities of other parts also exhibit a decreasing trend, so fatigue failure in early stage of service is mainly concentrated in planetary gear system and medium speed shaft bearings, and other parts can also fail in later stage of service; the system reliability of gearbox is expected to decrease to about 0. 588 over a 20-year life cycle; combined with reliabilities of components, fault early warning can be realized for wind turbine gearbox. © 2025 Chinese Vibration Engineering Society. All rights reserved.