Abstract Floating offshore wind turbines are becoming more attractive to the wind industry due to their capability to operate larger turbines in deeper waters. The floating support structures are anchored to the seabed via mooring chains to impede the structure's unwanted movements. The combination of cyclic stresses and the corrosive marine environment makes the floating support structures vulnerable to corrosion pitting and subsequently fatigue crack initiation and propagation. In this study a framework is proposed to simulate fatigue crack growth from multiple corrosion pits at critical spots of the Spar-type floating support structures to examine the status of the crack during several years of operation. The proposed advanced fracture mechanics based approach provides a methodology to assess the integrity of the structure and subsequently plan for preventive or curative maintenance. The crack growth rate is examined for both singular and multiple cracks at different R ratios and for different stress levels using ABAQUS XFEM. Following numerical simulations, a sensitivity analysis is carried out using Crackwise software for different values of plate thickness, R ratio and initial crack size. The numerical results are discussed in terms of the corrosion pitting effects on fatigue life assessment of floating offshore wind turbines.

中文翻译：

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浮动式海上风力发电机支撑结构的结构完整性评估

摘要 浮动式海上风力涡轮机由于能够在更深的水域运行更大的涡轮机，因此对风力行业越来越有吸引力。浮动支撑结构通过系泊链锚定在海床上，以阻止结构的不必要移动。循环应力和腐蚀性海洋环境的结合使浮动支撑结构容易受到腐蚀点蚀和随后的疲劳裂纹萌生和扩展。在这项研究中，提出了一个框架来模拟 Spar 型浮动支撑结构关键点处多个腐蚀坑的疲劳裂纹扩展，以检查几年运行期间裂纹的状态。提议的基于先进断裂力学的方法提供了一种方法来评估结构的完整性并随后计划预防性或治疗性维护。使用 ABAQUS XFEM 检查不同 R 比和不同应力水平下的单裂纹和多裂纹的裂纹扩展速率。在数值模拟之后，使用 Crackwise 软件对板厚、R 比和初始裂纹尺寸的不同值进行敏感性分析。数值结果根据腐蚀点蚀对浮动海上风力涡轮机疲劳寿命评估的影响进行了讨论。使用 Crackwise 软件对不同的板厚、R 比和初始裂纹尺寸值进行敏感性分析。数值结果根据腐蚀点蚀对浮动海上风力涡轮机疲劳寿命评估的影响进行了讨论。使用 Crackwise 软件对不同的板厚、R 比和初始裂纹尺寸值进行敏感性分析。数值结果根据腐蚀点蚀对浮动海上风力涡轮机疲劳寿命评估的影响进行了讨论。