Optimum Technology On Support Structures Of Offshore Wind Turbine Based On Dynamic Properties

As a kind of clean energy, offshore wind generation is expected to increase significantly in the near future. The technology of it involves multi-fields which are aerodynamics, structural dynamics, material science, marine environment science, mechanical engineering, electric engineering, control technology, offshore installation technology, etc. Cost reduction asks for multi-MW wind turbines and deepwater locations. The requirement for reliability and economics of support structures is one of major challenges corresponding to the development of offshore wind turbines (OWTs).Considering comprehensively the characters of support structures of offshore wind turbines with pile foundation, dynamic properties and optimum technology of monopile and lattice (jacket) structures are researched based on those existing in the literature. Main contents and conclusions in this thesis are summarized as follows:Mathmatic models of monopile and lattice (jacket) support structures of OWTs are constructed by use of the theory of generalized single-degree-of-freedom system. Principal parameters of support structures are brought forward based on it for further finite element simulation. Parameters of pile foundation, support structures, tower, OWT and marine environment are assorted by sensitive analysis. Reseach shows that structural lectotype and economic analysis can be down by soft-stiff design scheme through relatively few parameters, which are only bound up with offshore wind turbine and steel tower.Detailed numerical examples are carried on for the comparison of monopile structures and lattice structures with different wind turbine,waterdepth and hubheight. Study shows that lattice structure is an economic drive for multi-MW OWT and deepwater exploitation.Structural feasibility of using jacket platforms of oil & gas farm as support structures of OWTs is discussed based on the findings above. Some useful conclusions and possible mitigation techniques are drawn for the future design of this type structures when one seeks to layout a new oil farm power system or rebuild decommissioned oil platforms for support structures of OWTs.On the basis of ANSYS 11.0 APDL, the optimum simulation platforms of monopile and lattice support structures of OWTs are developed. It allows users to generate batches of structural lectotype and economic analysis automatically with different OWTs parameters and marine environment parameters.