Reliability Analysis Of Support Structure Of The Offshore Wind Power Project

In recent years, China began to develop offshore wind power project. Supporting structure is a major component of offshore wind power project. Monopile structure is one of the most common offshore wind power project, but has not been specific applied in our country. In this paper, preliminary study feasibility of the support structure used in our country, calculate and analyze the reliability index of this structure, hoping for future research to provide some valuable information.For the correlation between extreme wind and waves loads, a random sampling method based on Nataf transformation of the correlative non-Gaussian distributions is proposed. Applying this method the correlation of extreme values between mutually independent load effects and correlative load effects is dicussed. Through numerical simulation and actual load effect calculation, verified the validity of the method. Different fitting methods for wind and wave load effects are evaluated, and least square method is proved more suitable than the moment method.Application of Archimedean Copula functions to construct the joint probability distribution of wind and waves, the Gumbel function is considered to be best for Weizhou Islands by different test methods, andχ2 test is the most efficient test method of all. Shortcomings of several common return periods are analyzed. Secondary Return Period is constructed by the Archimedean Copula-based C-measure, the definition of which is stringent, the result of which is closer to the return of load effects Period by theoretical analysis and data analysis.Several system reliability methods are discussed for the mono pile supporting structure of offshore wind power project. With finite element analysis software ANSYS and scientific computing software MATLAB, using response surface method and advanced first order reliablility method to solve the structural system reliability index, and a complete feasible structural system reliability method is established. Base on stationary binomial random process, establishing earthquake, wind, waves and currents distribution functions, referring to DNV specification, using JCSS load combination method, considerring the different limit state functions, calculate the reliability index of the supporting structure. Sensitivity of random variables is analysised and random variables having a major impact on structural reliability are discussed. The effect of the correlation between wind and waves on the reliability index is studied.