Reliability Assessment Method for Offshore Wind Turbine Gear Structures Considering Strength Degradation

An analytical calculation method based on generalized polynomial chaos and maximum entropy model is proposed for the gear structure of an offshore wind turbine. It is difficult to solve multidimensional complex nonlinear integrals in structural reliability assessment. First, considering the fatigue damage of gear caused by wind load, a time-varying reliability model is established taking into account the strength degradation of gear structure. Secondly, based on the uncertain distribution of random wind load and gear material structure, the original complex random model is transformed into a proxy model of orthogonal polynomial sum by introducing the generalized polynomial chaos expansion method. On this basis, the expansion coefficients and the orthogonal basis functions of the agent model are used to obtain the first four order moments of the origin of the structure function, which is used as a constraint for the fatigue reliability of the gear structure; the probability density function of the fatigue failure of the gear is calculated based on the maximum entropy principle, and the structural reliability index is solved by the direct integration method. Finally, the effectiveness of the proposed method is verified by an example using the calculation results of the Monte Carlo method as a reference. ©2023 Chin.Soc.for Elec.Eng.