Abstract Monopiles and gravity base foundations (GBF) are two of the most commonly used foundations for offshore wind turbines. As resonance can cause damage and even failure of wind turbines, understanding the difference between the dynamic responses of monopiles and GBFs under free vibration is important. However there is little experimental data regarding their natural frequency, especially from model tests carried out at correct stress levels. This paper presents the results of novel monopile and GBF tests using a centrifuge to directly determine the natural frequency (fn) of the foundation-soil system. The natural frequencies of wind turbine monopiles and GBFs in centrifuge models were measured during harmonic loading using a piezo-actuator, with the results confirming that soil-structure interaction must be considered to obtain the system’s natural frequency as this frequency reduces substantially from fixed-base values. These results will contribute in preventing resonance induced damage in wind-turbines.

中文翻译：

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使用离心机模型比较沙地海上风力发电机单桩和重力基础的动力响应

摘要 单桩和重力基础（GBF）是海上风力发电机最常用的两种基础。由于共振会导致风力涡轮机损坏甚至失效，因此了解自由振动下单桩和 GBF 的动态响应之间的差异很重要。然而，关于其固有频率的实验数据很少，尤其是在正确的应力水平下进行的模型测试。本文介绍了使用离心机直接确定地基-土壤系统的固有频率 (fn) 的新型单桩和 GBF 测试的结果。离心机模型中风力涡轮机单桩和 GBF 的固有频率是在谐波加载期间使用压电执行器测量的，结果证实，为了获得系统的自然频率，必须考虑土壤-结构相互作用，因为该频率从固定基值大幅降低。这些结果将有助于防止风力涡轮机中的共振引起的损坏。