Dynamic Analysis and Reliability Prediction of Wind Turbine Gearbox Under Uncertain Excitation Conditions

Abstract Wind turbine drivetrains experience variable aerodynamic loads, which can significantly impact their dynamic response and reliability. This study investigates how uncertainty in wind speed and inflow angle propagates from aerodynamic loading to gearbox failure risk and drivetrain dynamics. A blade-element aerodynamic model will be coupled with a probabilistic torque-based limit-state formulation. This will be done using first- and second-order reliability methods and Monte Carlo simulation for reliability assessment. The resulting critical aerodynamic conditions will be applied to a five-inertia torsional model that represents a multistage gearbox with a planetary stage, two parallel gear stages, and flexible shafts. We hypothesize that aerodynamic uncertainty is the only factor that significantly influences failure probability, and that critical aerodynamic conditions produce increased torsional and speed fluctuations in the drivetrain.