Validation of a finite-element model of a wind turbine blade bearing

Finite-element analysis is the only means to determine the load situation of slewing bearings with complex interfaces. For reliable results, the finite-element model needs to be validated by comparing the simulation results against measurement results. Most published finite-element bearing models of slewing bearings are not validated at all, and none of the publications investigate the accuracy of the experimental results. For the present work, the authors tested multiple double-row four-point contact ball bearings to compare them with simulation results. As the ball forces cannot be measured directly, strain gauges on the outer bearing ring were used to validate the model. To minimize the computational effort, the ball-raceway contact is modeled with nonlinear spring elements. The experimental results show high deviations for different pitch angles of the bearing at constant load levels. Nevertheless, the mean strain gauge values are reproducible with each tested bearing. That allows a comparison with the simulation and derives a test scenario of at least one bearing with different pitch positions at constant load to validate a bearing simulation. The result of this work is a validated bearing and test rig model.