Analysis on safety performance of wind turbine pitch bearing structure considering the influence of extreme loads

The structural components failure of wind turbine pitch bearing system under extreme multiaxial loading conditions significantly affects operational safety and reliability. In this regard, this paper presents a method for safety performance assessment of pitch bearing structural components. Firstly, finite element mesh model and fatigue analysis model of pitch bearing structural components were established. The contact characteristics of the pitch bearing’s rolling element and raceway under various extreme combined load conditions were investigated, and the safety performance of the sealing structure was evaluated. Finally, the fatigue life assessment of the pitch bearing structural components under extreme loads ranges was accomplished using the Markov matrix of the overturning moment at various angles. The results show that the accuracy of the pitch bearing finite element mesh model are validated. Under the overturning moment Markov matrix over the entire angular range, the cumulative fatigue damage indices of the pitch bearing structural components are less than 1, no fatigue failure occurs during the 20-year design life cycle. The pitch bearing inner ring bolts are highly susceptible to damage under extreme loading and should be designed with particular concern.