Dynamic Coupling Analysis Of The Offshore Wind Turbine Monopile Structure In The Specifically Sea

Nowadays, it is well known that the World's population is exploding; the social economy is increasingly developing and the energy source consumption is going up; the fossil energy gets exhausted day and day. In addition, the exploitation results in a great deal of pollution. So, improving the energy framework and using the renewable energy have attracted the world's eye.Wind resources can make an important contribution to the future energy demand and climate protection. Theoretically, the energy requirement is fulfilled by only 1% wind resource of the World's. As a reliable technique, compared with the other renewable energy source techniques, wind power is more commonly form in wind resource.At present, because of many advantages, such as the abundance marine resource, the little use of lands, the facility selection to location, the unconstraint of the environment, especially, the high speed of the wind, the little intensity of the turbulent current, the abundance production of the wind power generate, the plenty using of wind power, the more enormous turbine income 20%-40%coming from the offshore wind power than the onshore wind power, the large wind power farms move from onshore to offshore. My country owns the extensive sea in the east which is near to the electrical load centre (the economical advanced zone but a lack of electric power) which depth of water is 50m. As the well developing of its techniques, the wind power generation must be the primary improving energy in our costal regions of East China Sea.But the support structure which is installed in offshore areas is more costly than in onshore. Paying more attention to the economical foundation will be the critical research about the offshore wind power generation. There is a large turbine on the top of the monopile structure which is different from the normal offshore structures. So not the site condition but the turbine steady condition , such as power production, idling and stand-still, take critical effect on the structure.In this paper, firstly, in the analysis of the static strength, the finite element model is established by the SESAM which is good at the calculation of the pile soil interaction. The stiffness, the strength and the stability are checked by the working stress method from the API standard.And then, the software ANSYS is used to establish the finite element model for the dynamic analysis. In this establishment, the turbine is simplified to the mass element, and the same to the equipment. The Pile soil interaction is simulated by the equivalent pile. After the establishment, the Block-Lanczos method is selected for the calculation of the structure's natural frequency .It is shown that the result isn't coincide with the turbine's natural frequency.Finally, during the dynamic coupling analysis , the operating condition and the shutdown condition are compared and the results indicated that:1) in Bohai area, the dynamic response of structure is dominated by the load combination with ice; 2) on extreme condition, the turbine in shutdown state still contributes a lot to its substructure.The development of the offshore wind turbine generation is contributed by the study of its foundation. It is a long-term valuable research .At present , based on the dynamic characteristic analysis and the dynamic coupling analysis of the monopile under the combined load effect, it is proposed that the turbine load is the crucial effect factor and should be stressed on. The research provides not only references but also reliable information for the construction of the offshore wind turbine structures.