Study On Several Problems Of Offshore Wind Farm Wind Turbine Foundation Design

The development of offshore wind power applied to the national product has brought huge benefits, on the one hand, to reduce the environmental pollution caused by the use of fossil fuels, on the other hand, the development of renewable and clean energy to promote sustainable human development, with thetechnology matures, China also have strong support. But the technology for our country is still in its infancy, some of the key issues of independent research and development is still blank, and no industry standards governing the design and development of this domestic technical personnel to respond positively to carry out. Two important issues for the construction of offshore wind farms in the simulation of the application of the finite element software-unequal thickness tube butt welding welding defects on the stress concentration and different forms plie-to-sleeve grounted connections design axial capacity performance, the main contents are as follows:Unequal thickness tube butt welding welding defects on the stress concentration simulation:(1) Determine the unequal thickness tube butt weld stress concentration caused by the mechanical nature of stiffness mutation;(2) Select two typical butt weld connection, when its existence welding defects, welding defects parameters d、k on the stress concentration factor, the results show that the two alignment on the stress concentration factor complex;(3) Compared to the same weld defects parameters, both aligned on the stress concentration factor, the results showed that the wall thickness center-aligned connection better than the wall thickness of the inner wall of alignment connection, and the former stress concentration factor is reduced by at least about16%;(4) Analysis of different parameters d、k and the alignment of the two connection methods exist welding defects and the defect area on the opposite side of the stress concentration factor, the results show that the presence of welding defects of its corresponding end of another welding weld toe the stress concentration phenomenon will play to ease the release of the role of welding defects on opposite sides of the degree of stress concentration is much smaller than the degree of stress concentration welding defects;Grouting connection section axial capacity simulation:(1) First, try to calculate the contact parameters by using finite element analysis software, and then the four-group model DNV procedures while using the finite element method and its bearing capacity is calculated; (2) The results of a single model analysis compared the performance of different models designed bearing capacity and bearing capacity of the bearing capacity and DNV procedures contrast the finite element calculation, results show that the different model design stress concentration area mostly for grouting stone body different ends of stress concentration, model bearing capacity performance and load values Overall, the first group (short grounted connection length without shear keys) and the second group (short grounted connection length with shear keys) compared to the second set of models better bearing performance; compared to the second group and the third group (long grounted connection length with shear keys) a third set of optimum; the second group compared with the fourth group of the fourth group (conical grouted connection space with shear keys) of optimum.