Time-varying mesh stiffness modelling of offshore wind gearboxes under multi-fault modes

With the development of more complex offshore wind power generation structures, the operational stability and reliability of wind turbine units have gradually begun to confront significant challenges, particularly concerning gearbox failure issues. Notably, constructing fault datasets has been a persistent challenge due to problems such as inefficiency and exorbitant costs. To address this issue, this study proposes an advanced modelling and analysis method for time-varying gear meshing stiffness, aiming to enhance the accuracy and efficiency of fault dataset construction. To improve the simulation model’s ability to reflect real-world operating conditions, a multi-degree-of-freedom translational–torsional coupled dynamic model of a wind turbine gearbox under multiple non-linear factors was established using the Lagrangian equation. Unlike traditional single-fault models, this study also introduces an analysis method for time-varying gear meshing stiffness under multi-fault composite conditions by integrating an improved energy analysis approach. The research findings indicate that the proposed time-varying gear meshing stiffness model and analysis method can effectively construct fault datasets and facilitate the observation of fault characteristics.