Critical assessment of end of design life fatigue damage analysis for life-extension of offshore wind infrastructure

海上风能是一种高效的可再生能源，它日益成为实现英国短期和长期能源需求的首选解决方案。根据英国的可再生能源路线图和到2030年海上风电装机容量达到50吉瓦的国家目标，未来几十年将推动更多海上风电场的部署。英国绝大多数的海上风力涡轮机是用单桩基础支撑的，单桩基础是由焊接大厚度钢板制成的。这些支撑结构在使用过程中承受着严峻的循环荷载条件；因此，它们需要设计抗疲劳失效，以达到预期的目标寿命，通常在20到25年之间。该博士项目的目的是评估支撑结构在初始设计寿命结束时的疲劳损伤程度，并探索延长现有资产寿命的可能工程解决方案。

An efficient source of renewable energy, which is increasingly the preferred solution for realising the UK's short- and long-term energy demand, is offshore wind. According to the UK's Renewable Energy Roadmap and the national target to reach up to 50 GW of installed offshore wind capacity by 2030, deployment of further offshore wind farms will be boosted over the coming decades. The dominant majority of the UK's offshore wind turbines are supported using monopile foundations which are fabricated by welding large thickness steel plates. These support structures are subjected to severe cyclic loading condition during service; therefore, they need to be designed against fatigue failure for a desired target life which is typically between 20 and 25 years. The aim of this PhD project is to evaluate the level of fatigue damage in the support structures at the end of initial design life and explore possible engineering solutions for life extension of the existing assets.