Fatigue analysis of a mid-size wind turbine hub at various load conditions was requested. Furthermore, a comparison between welded and cast hubs was needed.


A finite element simulation was set up applying loads to assess critical areas of the hub. Using the adequate load pattern, different load cases were determined: at start-up, during standard operation, in parked condition and at shutdown.
Fatigue damage accumulation was computed according to Miners rule and rainflow counting method.


The computation demonstrated that it was possible to use a welded hub.