Influence of superelement support structure modeling on the loads on an offshore wind turbine with a jacket support structure

In aero-hydro-servo-elastic tools used for load simulations of offshore wind turbines (OWTs), the joint flexibilities of the support structures are generally not modeled in detail. This may lead to lower accuracy of the resulting loads. In this study, the influence of a superelement modeling approach (which includes the modeling of detailed joints) compared to the formerly used beam modeling approach on the simulated loads is investigated based on a generic 5MWOWTwith a jacket support structure. To confirm the feasibility of the superelement approach, the mass and eigenfrequencies of the beam and superelement jacket models are compared to those of a reference shell model. A static analysis is conducted to pre-check the different load bearing behavior of the two models. Time domain simulations are conducted with the software ADCoS-Offshore using a reduced fatigue load case set with two complete OWT models that include beam and superelement jackets respectively, and the results are analyzed. Conclusions are drawn regarding the necessary model fidelity for the simulations of this type of OWT under the given conditions.