Experimental study on seismic vibration control of an offshore wind turbine with TMD considering soil liquefaction effect

• Published in: Marine structures 2021-05, Vol.77, p.102961, Article 102961
• Main Authors: Lin, Ging-Long, Lu, Lyan-Ywan, Lei, Kai-Ting, Liu, Kuang-Yen, Ko, Yung-Yen, Ju, Shen-Haw
• Format: Article
• Language: English
• Subjects: Clean energy; Earthquake dampers; Earthquake loads; Earthquakes; Energy dissipation; Energy exchange; Liquefaction; Model testing; Ocean floor; Offshore; Offshore energy sources; Offshore wind turbine supporting structure; Pile foundations; Reliability aspects; Reliability engineering; Rotation; Seismic mitigation; Shake table tests; Shaking table test; Soil; Soil liquefaction; Soils; Structural reliability; Tuned mass damper; Turbine blades; Turbine engines; Turbines; Vibration; Vibration control; Vibration isolators; Vibrations; Wind effects; Wind farms; Wind power; Wind turbines
• ISSN: 0951-8339; 1873-4170
• DOI: 10.1016/j.marstruc.2021.102961

Wind energy is clean and sustainable. Taiwan is establishing offshore wind farms using wind turbines in the Taiwan Strait. However, these are located in an earthquake-prone area with sandy seabed conditions. To ensure their safety and reliability, the turbines’ support structure must be protected against wind, waves, and seismic loads. Tuned mass dampers (TMDs) are commonly employed to reduce structural vibrations. A TMD is more simply incorporated into turbine structures than are other energy dissipation devices. In this study, a 1:25-scale test model with a TMD was constructed and subjected to shaking table tests to experimentally simulate the dynamic behavior of a typical 5-MW wind turbine with a jacket-type support structure and pile foundation. The scaled-down wind turbine model has a nacelle without rotating blades; therefore, the aerodynamic and rotational effects due to the rotating blades were ignored in this study. A large laminar shear box filled with saturated sandy ground was used to simulate the typical seabed conditions of Taiwanese offshore wind farms. The TMD system was designed to be tuned the first-mode frequency of the test model. Two ground accelerations, selected by considering wind farm site condition and near-fault characteristics, were used for excitation in the test. The responses of the test model with and without the TMD system were compared, and the influence of soil liquefaction on the effectiveness of TMD vibration control was addressed. •Vibration control of a wind turbine model using a tuned mass damper was tested.•Test setup included a 1/25 scaled-down model placed in a large laminar shear box.•The tested wind-turbine system has a jacket-type structure and pile foundation.•Issues about soil liquefaction effect and damper stroke demand are discussed.•Tuned mass damper is effective for wind turbine even when soil liquefaction occurs.