Probabilistic dynamic optimization design for support structure of offshore wind turbines

Probabilistic dynamic optimization design for a tripod supporting structure of offshore wind turbines was studied. Compared with onshore wind turbines, the cost of supporting structures of offshore wind turbines was higher and their repairing and installation costs induced by dynamic environmental loads were also larger, so the reliability of supporting structures of offshore wind turbines had to be taken into account. The method of probabilistic dynamic optimization design was adopted to reduce costs and fully consider safety issues due to uncertainties. Firstly, based on simulations of dynamic environmental loads, the global dynamic responses of an offshore wind turbine were analyzed and therefore the response probabilistic constraint conditions were identified. Then, design variables were simplified with the design of experiment (DOE) method and relationships between variables and responses were constructed with approximation models. Last, global optimization algorithms were adopted based on approximation models for probabilistic dynamic optimization design of a tripod supporting structure. Optimized results not only satisfied strength and stiffness requirements but also had a lower cost and a better reliability. The results of examples showed that the proposed method is feasible