The main intention of the present study is to reduce wind, wave, and seismic induced vibrations of jacket- type offshore wind turbines （JOWTs） through a newly developed vibration absorber, called tuned liquid column...The main intention of the present study is to reduce wind, wave, and seismic induced vibrations of jacket- type offshore wind turbines （JOWTs） through a newly developed vibration absorber, called tuned liquid column gas damper （TLCGD）. Using a Simulink-based model, an analytical model is developed to simulate global behavior of JOWTs under different dynamic excitations. The study is followed by a parametric study to explore efficiency of the TLCGD in terms of nacelle acceleration reduction under wind, wave, and earthquake loads. Study results indicate that optimum frequency of the TLCGD is rather insensitive to excitation type. In addition, while the gain in vibration control from TLCGDs with higher mass ratios is generally more pronounced, heavy TLCGDs are more sensitive to their tuned frequency such that ill-regulated TLCGD with high mass ratio can lead to destructive results. It is revealed that a well regulated TLCGD has noticeable contribution to the dynamic response of the JOWT under any excitation.展开更多
调频气压液柱阻尼器(tuned liquid column gas damper,TLCGD)是一种从调频液柱阻尼器发展而来的新型而有效的结构减震装置。在U/V形阻尼器液柱上加上封闭式气压不仅增加了它的使用范围,使频率扩大到5Hz,并且提高了结构的有效阻尼。由广...调频气压液柱阻尼器(tuned liquid column gas damper,TLCGD)是一种从调频液柱阻尼器发展而来的新型而有效的结构减震装置。在U/V形阻尼器液柱上加上封闭式气压不仅增加了它的使用范围,使频率扩大到5Hz,并且提高了结构的有效阻尼。由广义Bernoulli方程推导出液体在管道中的运动方程并等价线性化。本文分析了非对称结构平移-扭转耦联振动的动力特性。当结构在地震和强风作用下发生以平移为主的动力反应,该阻尼器的最佳位置使到速度中心的距离最大。通过振型优化,Den Hartog公式得到阻尼器的最优参数(阻尼比和调谐频率比),考虑邻近多个振型的相互影响,状态空间优化使得结果更为合理。用1个3层的偏心结构作为算例,进行优化计算。数值结果表明,这种优化方法得到的参数使得调频气压阻尼器对结构的平动-扭转反应起到较好的减振效果。展开更多
非对称结构在地震和强风作用下会产生平移-扭转耦联振动,当速度中心位于平面内时,将调频气压液柱阻尼器(tuned liquid column gas damper,TLCGD)的水平管道设计成封闭的区域包含该速度中心,这种新型的阻尼器称为扭转调频气压液柱阻尼器(...非对称结构在地震和强风作用下会产生平移-扭转耦联振动,当速度中心位于平面内时,将调频气压液柱阻尼器(tuned liquid column gas damper,TLCGD)的水平管道设计成封闭的区域包含该速度中心,这种新型的阻尼器称为扭转调频气压液柱阻尼器(torsional tuned liquid column gas damper,TTLCGD)。对于控制对称结构纯扭转振动,该装置同样适合。由广义Bernoulli方程推导出管道中的液体在地震作用下的运动方程并等价线性化。通过振型优化Den Hartog公式得到阻尼器的最优参数(阻尼比和调谐频率比),考虑邻近多个振型的相互影响,状态空间优化使得结果更为合理。用1个3层的偏心结构作为算例,进行优化计算。数值结果表明,这种优化方法得到的参数使得扭转调频气压阻尼器对结构的平移-扭转反应起到较好的减振效果。展开更多
文摘The main intention of the present study is to reduce wind, wave, and seismic induced vibrations of jacket- type offshore wind turbines （JOWTs） through a newly developed vibration absorber, called tuned liquid column gas damper （TLCGD）. Using a Simulink-based model, an analytical model is developed to simulate global behavior of JOWTs under different dynamic excitations. The study is followed by a parametric study to explore efficiency of the TLCGD in terms of nacelle acceleration reduction under wind, wave, and earthquake loads. Study results indicate that optimum frequency of the TLCGD is rather insensitive to excitation type. In addition, while the gain in vibration control from TLCGDs with higher mass ratios is generally more pronounced, heavy TLCGDs are more sensitive to their tuned frequency such that ill-regulated TLCGD with high mass ratio can lead to destructive results. It is revealed that a well regulated TLCGD has noticeable contribution to the dynamic response of the JOWT under any excitation.
