海上浮式风机的一体化建模及其整体可靠性

Integrated dynamic modeling and global reliability analysis of floating offshore wind turbines

基于整体可靠性的结构设计方法是保障海上浮式风机结构安全性与经济性,使得浮式风机能够适用于大规模深远海风能开发的关键。本文首先简要评述了浮式风机结构建模与可靠性分析的主要方法。为了分析风-浪联合作用下浮式风机结构的整体可靠性,介绍了结合多体动力学理论与有限元方法的浮式风机结构一体化耦合动力学分析模型。同时基于我国南海某场址长期风-浪再分析数据,并采用Copula方法建立风-浪多参数非线性相关的联合概率分布模型,从而合理考虑风-浪联合作用。在此基础上,引入概率密度演化理论,实现浮式风机结构的整体可靠性高效分析。针对海上风机结构国际设计规范中定义的极端风剪不利工况,采用上述方法进行了额定风速和极端风剪条件下海上单柱式浮式风机结构的整体可靠度分析。

Structural design methods based on global reliability are crucial to the safety and economy of floating offshore wind turbines that are designed for harvesting wind energy in the deep sea.The dynamic modeling and reliability assessment of floating offshore wind turbines are first briefly reviewed.Then the main attention of the present study is paid to the global reliability assessment of floating offshore wind turbines.To this end,an integrated dynamic model of floating offshore wind turbines is introduced by synthesizing the multibody dynamics and the finite element method so that the responses of floating offshore wind turbines can be analyzed.To reasonably consider the joint effects of wind and wave loads on the structure,a joint probability distribution model of multiple nonlinearly dependent environmental variables is adopted using the Copula method based on long-term wind and wave data from the South China Sea.On this basis,the probability density evolution method is employed to evaluate the global reliability of a spar-type floating offshore wind turbine under rated wind conditions with extreme wind shear.The present study provides a framework for global reliability analysis of floating offshore wind turbines,laying the foundation for performing reliability-based optimization designs of floating offshore wind turbines.