Superelement approach in fully coupled offshore wind turbine simulation: Influence of the detailed support structure modelling on simulation results for a 5-MW turbine on a tripod substructure

Fatigue design and certification of offshore wind turbines (OWT) is performed using aero-servo-hydro-elastic time domain simulations. So far, the local flexibility of the joints in branched OWT support structures has been neglected in those simulations. In this work, a superelement approach, allowing for detailed modeling of local joint flexibility in the OWT design tool ADCoS-Offshore, is presented. The influence of this simulation approach, taking into account joint stiffnesses with the same level of accuracy as detailed finite element models, is described and interpreted using the example of a realistic 5 MW OWT on a tripod in 45 m of water. Further, recommendations for modeling of turbines on this type of structure are given.