Lectotype Optimization And Reliability Analysis For Offshore Wind Turbine Foundation Structure

Wind power has been the fastest-growing green energy technology in the world, and the maritime wind energy resouces is abundant. Druring last several decades, the construction of offshore wind farms was extensive application through out Europe, recently it has developed quickly the tide of wind power in North America and Asia countries. But it's still one of the currently main challenges that whether the design is economical and reasonable. Structure type and reliability of wind turbine foundation which belongs to one proposed offshore wind farm were studied and analysised in this paper, referring to project examples and relevant experiences of domestic and foreign offshore wind farms.(1) Fuzzy optimum decision of offshore wind farm gravity foundationThe selection of foundation structure type has significant effect on layout of wind turbines and the construction cost of wind farm. So we must select resonable and economical foundation structure type. However the selection involves many complex factors, based on the Fuzzy comprehensive evaluation method of fuzzy mathematics theory, combining professional knowledge and experts'experience, using fuzzy set theory to deal with the uncertain information, reducing human factors of arbitrary subjective judgments in the structure plan selection, finaly this paper made the fuzzy optimum selection of offshore turbine gravity foundation and got the satisfied outcome. The application of fuzzy optimum theory in structure lectotype optimization designing of engineering is feasible and reasonable.(2) Offshore gravity foundation size optimization and stability analysisAccording to port engineering norms and analysis of the geological and hydrological data about proposed wind farm, preliminary design of foundation has been done. And taking the lightest weight of the structure as object, take the anti-sliding stability, anti-overturning stability, subground stress as constraint, the structure size has been optimized.The final part is the structure stability calculation which contains anti-sliding stability analysis, anti-overturning stability analysis, and base stress analysis under design conditions.(3) Wind turbine foundation systerm Reliability calculationMarine structures are subject to environmental loads during its manufacturing process and service periods, such as wind, wave, current and sea ice loads. The reliability analysis should be done for the safty, applicability and economics of the structure. By way of testifying the reliability of the gravity wind teurbine foundation, a second-order moment of the checking point method was applied in this paper to calculated the reliability of the anti-sliding stability, anti-overturning stability, subground stress of offshore wind turbine foundation.Then these three primary failure mode composed a series systerm,this paper calculated the systerm reliability of the foundation,adopting a approximate method for calculating systerm failure probability.The results shows that the failure probability either single failure mode or structure systerm is quite low, the reliability is high and up to the safety requirement.