考虑桩基础柔性的海上风机结构可靠度安全评价研究

Research on reliability assessment of offshore wind turbine with the flexible pile foundation

为了解决海上风机结构可靠性评价模型普遍存在的不能准确模拟荷载间的耦合效应的问题,文章基于OpenFAST开发了一种全耦合海上风机支撑结构可靠性评估模型。考虑到桩土相互作用对风机结构响应的显著影响,文章基于耦合弹簧模型建立了具有柔性单桩基础的NREL5MW海上风机模型。选取海上风机结构的叶尖塔筒间隙及桩基泥面平动位移作为典型失效模式,分别开展了考虑柔性桩基的海上风机结构在正常运行及停机工况下的结构安全评价。研究结果不仅验证了该模型能够高效准确地开展海上风机结构可靠度安全评价,还揭示了波浪荷载是导致桩基发生平动位移的主导荷载。

In order to solve the general problem that the current offshore wind turbine structural reliability assessment model cannot accurately simulate the coupling effect between loads,this study develops a fully coupled offshore wind turbine supporting structure reliability assessment model based on OpenFAST.Considering the significant influence of pile-soil interaction on the structural response of wind turbines,the NREL5MW offshore wind turbine model with flexible foundation was established in this study based on a coupled spring model.According to the relevant references,the blade tip clearance and the translational displacement of the foundation at the seabed are selected as the typical failure modes,and the structural safety evaluation of offshore wind turbine structures considering flexible foundations under normal operation and shutdown conditions is carried out respectively.The research results not only verify that the model can efficiently and accurately evaluate the reliability level of offshore wind turbine structures,but also reveal that wave loads are the dominant loads that cause translational displacement of the pile foundation.