Research On Integrated Analysis And Selection Method Of Monopile And Jacket Substructure For Offshore Wind Turbine

The offshore wind turbine is an increasingly emerging technology in the field of ocean engineering.The design and construction of offshore wind turbines is intrinsically multiple disciplinary,which involves aerodynamics,hydrodynamics,wind turbine system control and structural dynamics.In recent years,offshore wind power has developed rapidly in China with the support of relevant national policies.However,with the cancellation of the national electricity price subsidy,China's offshore wind power is about to enter the era of normal price,which makes it urgent to start reducing costs and increasing efficiency from every aspect.Among them,the cost of substructure accounts for 20% to 35% of the entire wind turbine,which causing the improvement of the traditional iterative analysis method used for the substructure design and the reasonable selection of the form of substructures have become particularly important.So the integrated analysis for monopile and jacket was studied and the design selection program for the same substructure was also developed in this thesis.(1)An integrated model of wind turbine-tower-substructure were built for the monopile and the jacket.A random turbulent wind field and a random wave field were applied to the integrated model,and time-domain simulation calculations were performed on the overall structures,which made the integrated analysis of fixed substructures for offshore wind turbines was achieved.The ultimate load,fatigue load and dynamic response calculated by the integrated analysis method and the traditional iterative analysis method were compared and analyzed.The results showed that the loads and steel consumptions could be significantly reduced by using the integrated analysis method.(2)Parameter analysis was carried out for offshore wind turbines of two substructure forms,monopile and jacket.By carrying out the integrated analysis and traditional iterative analysis under different wind and wave conditions,structural dynamic response and the advantages of integrated analysis under different wind and wave conditions were compared and analysised.(3)An orthogonal database of offshore wind turbine substructure was established by carrying out strict orthogonal calculations for various environmental parameters.On the basis of the orthogonal database,a design selection program for the monopile and jacket were developed,which could obtain a preliminary design result of an offshore wind turbine substructure suitable for the input environmental parameters by multivariate interpolation calculation according to the input values.Based on the selection program,further parameter analysis of the marine environment of the monopile and jacket was carried out,and the mutual influence law of various marine environment parameters and the application scope of the monopile and jacket were also analyzed.