Abstract The tower is an essential supporting structure for a Floating Wind Turbine (FWT). Due to the complexities of system structure and the environmental excitations, FWT towers present rather complicated loading characteristics, potentially threat the system reliability. This paper aims to reveal the FWT tower dynamics in wind-wave-current environments with a dedicated experimental apparatus. A new strategy is proposed to design the FWT structure. Then, extensive tests are conducted with different offshore environments and varying rotor operating conditions. Results show that the FWT tower loading presents complicated dynamic characteristics. The frequency response mainly consists of three parts: the low-frequency component associated with floater oscillations and wind excitations, the wave-frequency component induced by the linear wave loads, and the high-frequency component resulted from the rotor-nacelle assembly (RNA) operating and vibrations. The low- and wave-frequency responses increase with the wave height, while the high-frequency response amplifies with the aerodynamic loads. Vibrations transmit between the upper RNA and the lower floating platform through the tower structure, smearing the system stability and increasing the structure fatigue damages. Optimizations should be proposed to improve the FWT tower performance to suppress or isolate these unexpected vibrations.

中文翻译：

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基于波盆模型试验的浮式风力机塔架载荷特性试验研究

摘要 塔架是浮动式风力发电机（FWT）的重要支撑结构。由于系统结构和环境激励的复杂性，FWT塔呈现出相当复杂的负载特性，潜在地威胁到系统的可靠性。本文旨在用专用的实验装置揭示风浪流环境中的 FWT 塔动力学。提出了一种新的策略来设计 FWT 结构。然后，在不同的海上环境和不同的转子运行条件下进行了广泛的测试。结果表明，FWT塔载荷呈现复杂的动态特性。频率响应主要由三部分组成：与浮子振荡和风激励相关的低频分量，由线性波浪载荷引起的波频分量，以及由转子 - 机舱组件 (RNA) 操作和振动引起的高频分量。低频和波频响应随着波高的增加而增加，而高频响应随着气动载荷的增加而放大。振动通过塔架结构在上部RNA和下部浮动平台之间传递，影响系统稳定性，增加结构疲劳损伤。应提出优化建议以提高 FWT 塔性能，以抑制或隔离这些意外振动。振动通过塔架结构在上部RNA和下部浮动平台之间传递，影响系统稳定性，增加结构疲劳损伤。应提出优化建议以提高 FWT 塔性能，以抑制或隔离这些意外振动。振动通过塔架结构在上部RNA和下部浮动平台之间传递，影响系统稳定性，增加结构疲劳损伤。应提出优化建议以提高 FWT 塔性能，以抑制或隔离这些意外振动。