Vibration attenuation performance of wind turbine tower using a prestressed tuned mass damper under seismic excitation

With the rapid development of large megawatt wind turbines,the operation environment of wind turbine towers(WTTs)has become increasingly complex.In particular,seismic excitation can create a resonance response and cause excessive vibration of the WTT.To investigate the vibration attenuation performance of the WTT under seismic excitations,a novel passive vibration control device,called a prestressed tuned mass damper(PS-TMD),is presented in this study.First,a mathematical model is established based on structural dynamics under seismic excitation.Then,the mathematical analytical expression of the dynamic coefficient is deduced,and the parameter design method is obtained by system tuning optimization.Next,based on a theoretical analysis and parameter design,the numerical results showed that the PS-TMD was able to effectively mitigate the resonance under the harmonic basal acceleration.Finally,the time-history analysis method is used to verify the effectiveness of the traditional pendulum tuned mass damper(PTMD)and the novel PS-TMD device,and the results indicate that the vibration attenuation performance of the PS-TMD is better than the PTMD.In addition,the PS-TMD avoids the nonlinear effect due to the large oscillation angle,and has the potential to dissipate hysteretic energy under seismic excitation.

Seismic response of controlled structures with active multiple tuned mass dampers

Active multiple tuned mass dampers （referred to as AMTMD）, which consist of several active tuned mass dampers （ATMDs） with identical stiffness and damping coefficients but varying mass and control force, have recently been proposed to suppress undesirable oscillations of structures under ground acceleration. It has been shown that the AMTMD can remarkably improve the performance of multiple tuned mass dampers （MTMDs） and is also more effective in reducing structure oscillation than single ATMDs. Notwithstanding this, good performance of AMTMD （including a single ATMD illustrated from frequency-domain analysis） may not necessarily translate into a good seismic reduction behavior in the time-domain. To investigate these phenomena, a three-story steel structure model controlled by AMTMD with three ATMDs was implemented in SIMULINK and subjected to several historical earthquakes. Likewise, the structure under consideration was assumed to have uncertainty of stiffness, such as 4-15% of its initial stiffness, in the numerical simulations. The optimum design parameters of the AMTMD were obtained in the frequency-domain by implementing the minimization of the minimum values of the maximum dynamic magnification factors （DMF） of general structures with AMTMD. For comparison purposes, response analysis of the same structure with a single ATMD was also performed. The numerical analysis and comparison show that the AMTMD generally renders better effectiveness when compared with a single ATMD for structures subjected to historical earthquakes. In particular, the AMTMD can improve the effectiveness of a single ATMD for a structure with an uncertainty of stiffness of 4-15% of its initial stiffness.

Vibration Control of a Gym Floor Using Tuned Mass Dampers: A Numerical Analysis

This work presents a study on excessive vibration problem occurring on concrete slabs, usually used on residential and commercial building floors. Even well designed slabs, according to ultimate and serviceability limit states criteria, can be vulnerable to undesirable vibrations that lead to user discomfort. A gym floor, that presented real excessive vibrations, located in a commercial building situated in the city of Brasilia,Brazil, was analyzed via Finite Element Method using ANSYS software. The first step in this analysis was to obtain natural frequencies and vibration modes, the structure presented low natural frequencies representing its flexible behavior. Then it was simulated a dynamic loading of people jumping, characteristic of this type of building occupation. Since it was observed the occurrence of excessive vibrations also in the numerical analysis, a Tuned Mass Damper (TMD) control system was proposed, looking for the best set of dampers to improve the control performance. The parameters for the best vibration reduction were obtained via a parametric study considering four different slabs varying dimensions and support conditions. Different models considering one and more TMDs, varying its placements and parameters, besides the frequency reference value to tune the damper were considered. An efficient control solution to this practical problem is presented to reduce its undesirable vibrations.

Optimal design theories of tuned mass dampers with nonlinear viscous damping

Optimal design theory for linear tuned mass dampers （TMD） has been thoroughly investigated, but is still under development for nonlinear TMDs. In this paper, optimization procedures in the time domain are proposed for design of a TMD with nonlinear viscous damping. A dynamic analysis of a structure implemented with a nonlinear TMD is conducted first. Optimum design parameters for the nonlinear TMD are searched using an optimization method to minimize the performance index. The feasibility of the proposed optimization method is illustrated numerically by using the Taipei 101 structure implemented with TMD. The sensitivity analysis shows that the performance index is less sensitive to the damping coefficient than to the frequency ratio. Time history analysis is conducted using the Taipei 101 structure implemented with different TMDs under wind excitation. For both linear and nonlinear TMDs, the comfort requirements for building occupants are satisfied as long as the TMD is properly designed. It was found that as the damping exponent increases, the relative displacement of the TMD decreases but the damping force increases.

Multiple Tuned Mass Damper Based Vibration Mitigation of Offshore Wind Turbine Considering Soil–Structure Interaction

The dynamics of jacket supported offshore wind turbine （OWT） in earthquake environment is one of the progressing focuses in the renewable energy field. Soil-structure interaction （SSI） is a fundamental principle to analyze stability and safety of the structure. This study focuses on the performance of the multiple tuned mass damper （MTMD） in minimizing the dynamic responses of the structures objected to seismic loads combined with static wind and wave loads. Response surface methodology （RSM） has been applied to design the MTMD parameters. The analyses have been performed under two different boundary conditions： fixed base （without SSI） and flexible base （with SSI）. Two vibration modes of the structure have been suppressed by multi-mode vibration control principle in both cases. The effectiveness of the MTMD in reducing the dynamic response of the structure is presented. The dynamic SSI plays an important role in the seismic behavior of the jacket supported OWT, especially resting on the soft soil deposit. Finally, it shows that excluding the SSI effect could be the reason of overestimating the MTMD performance.

Mitigation of Ice-Induced Vibrations for Offshore Platforms Using Tuned Mass Damper

The problems of ice-induced vibration have been noticed and concerned since the 1960s, but it has not been well resolved. One reason is that the dynamic interaction between ice and structure is so complicated that practical ice force model has not been developed. The recent full-scale tests conducted on jacket platforms in the Bohai Sea presented that ice could cause intense vibrations which endanger the facilities on the deck and make discomfort for the crew. In this paper, the strategy of mitigation of ice-induced offshore structure vibration is discussed. Based on field observations and understanding of the interaction between ice and structure, the absorption mitigation method to suppress ice-induced vibration is presented. The numerical simulations were conducted for a simplified model of platform attached with a Tuned Mass Danlper （TMD） under ice force function and ice force time history. The simulation results show that TMD can fa- vorably reduce ice-induced vibrations, therefore, it can be considered to be an alternative approach to utilize. Finally, the application possibilities of utilizing TMDs on other miniature offshore structures in ice-covered areas of marginal oil fields are discussed.

悬索桥竖弯涡振MTMD减振控制效果和参数优化研究

为研究多重调谐质量阻尼器(Multiple Tuned Mass Damper,MTMD)抑制桥梁单阶涡振的性能,建立桥梁结构-MTMD系统竖弯涡振广义单自由度动力方程,以某大跨度悬索桥为背景进行MTMD减振控制效果和参数优化分析。采用数值方法求解动力方程,获得系统在简谐涡激力下达到稳态谐振时结构的动力放大系数和MTMD对结构的附加模态阻尼比,并与单一频率调谐质量阻尼器(Single Tuned Mass Damper,STMD)的减振控制效果进行对比,然后以附加模态阻尼比为目标对MTMD进行参数优化。结果表明:MTMD比最优参数STMD拥有更宽的控制频带和更好的减振效果,经优化后的MTMD减振性能优于最优参数STMD。实际应用MTMD时,应选择较大广义质量、5~7种频率规格,并根据二者找到无量纲频率范围和各TMD阻尼比的惟一最优取值。

基于TMD的车致箱梁振动控制模型试验研究

为研究调谐质量阻尼器(tuned mass damper,简称TMD)在控制轨道箱梁结构振动中的应用,以高速动车组和CRTS-Ⅱ型板式无砟轨道-箱梁结构为原型,设计制作了几何相似比为10∶1的车-轨-桥耦合振动缩尺模型系统,分析了TMD在不同质量比、不同位置以及不同安装数量等工况下对箱梁顶板和翼板的减振效果。结果表明:TMD质量比为0.02时减振效果优于质量比为0.01时的减振效果,在考虑结构安全及经济性的条件下,可优先选择质量比更大的TMD;不同TMD安装位置对箱梁各部件的减振效果不同,安装TMD的板件处振动响应得到了明显抑制;安装2个TMD对箱梁结构的减振效果优于安装1个TMD,其减振范围也有所提升。研究结论可为高架轨道箱梁结构的减振设计提供参考。

预应变SMA⁃TMD对钢框架结构抗震性能影响研究

针对钢结构在地震激励下加速度响应过大的问题,介绍了一种将形状记忆合金(SMA)应用到调谐质量阻尼器(TMD)装置中的解决方案,利用SMA的特性实现有效的自复位和稳定的阻尼,将预应变SMA棒应用到TMD中,提高装置的阻尼性能。通过试验测试及有限元模拟,研究安装施加预应变SMA-TMD的钢框架抗震性能。结果表明:预应变SMA棒不仅有助于自复位,而且还能大大提高SMA-TMD的等效黏滞阻尼比;经过优化的SMA-TMD装置可以大大降低钢框架的地震动响应,并加快地震能量消耗。

Long-Term Effect of TMD on Vibration Control of An MDOF Offshore Fixed Platform

A three-dimensional fixed offshore platform in deep water modeled by the finite element method is studied in this paper. Analysis of the dynamic response of the MDOF structure is realized taking the non-linearity of the wave drag force and the wave-structure interaction into account. The structural response statistics, which have Gaussian distributions, are used to evaluate the vibration effect of the structure without TMD and with TMD. And an optimal method to design TMD controlling the first mode of the multi-mode structure is proposed. Moreover, the probabilities of occurrence of sea states at the platform site are considered for prediction of the long-term effect of a TMD. Simulation results demonstrate that the long-term effect of a well-designed TMD is good and the practical use is possible due to the good stability of its optimal parameters under different sea states.

桥梁抗风型TMD对车-桥耦合振动系统减振性能研究

为研究桥梁抗风型调谐质量阻尼器(tuned mass damper, TMD)对车辆荷载引起结构振动的减振效果,并揭示车载作用下的TMD激振机理,提出了基于模态动能演化的多自由度结构TMD控制方法,确定了安装TMD的最优设计参数和布设位置;考虑桥梁有限元模型动力求解的通用性,基于桥梁三维动力分析系统BDANS软件建立了车-桥-TMD动力耦合分析系统;以经典单自由度移动弹簧质量过简支梁模型为研究对象,分析了车-桥-TMD系统振动特性,结合某深水区非通航桥梁抗风型TMD工程实例分析了TMD对车致振动的减振效果和机理。研究结果表明:TMD行程幅值与减振效果呈现正相关特点,即行程幅值越大对车-桥动力效应引起的振动减振效果越好;安装TMD可以显著提高结构的等效阻尼比,满足等效阻尼比>1%的工程需求,提高桥梁结构振动的稳定性;TMD在一定条件下可以减小车辆通过时引发桥梁竖向位移冲击效应,最大可减少3%左右;TMD对车-桥2个子系统的加速度瞬态峰值均起到了一定的抑制效果,尤其对桥梁结构竖向振动加速度作用效果明显,安装TMD后的桥梁跨中竖向振动加速度RMS值减少约20%;对大跨钢箱桥梁而言,相比较小的车辆荷载冲击效应,一阶竖弯呈邻跨反对称特性的桥梁结构在车辆通行过程中更容易激起TMD,使桥梁结构获得更佳的减振效果。

基于气动措施和滑轮式TMD的人行景观桥涡振混合控制研究

为了解决传统式调谐质量阻尼器(tuned mass damper, TMD)在控制低频桥梁结构中弹簧静伸长过长的问题,介绍了滑轮式TMD及其用于结构振动控制时的特点,指出滑轮式TMD可以有效减小弹簧静伸长量。以一座人行景观桥为例,研究了采用气动措施和滑轮式TMD对该桥的涡振控制效果。风洞试验结果显示,在最优气动措施下,主梁的涡振振幅减少了一半以上,但仍未达到行人舒适性要求。基于Scanlan线性涡激力模型进行滑轮式TMD的优化设计,在气动措施的基础上进一步辅以滑轮式TMD进行涡振控制。分析结果表明,气动措施结合滑轮式TMD进行涡振控制能够满足行人舒适性要求,并确保滑轮式TMD质量块的工作行程不超过限值。通过同时采用气动措施和滑轮式TMD,可以满足主梁涡振限值、TMD弹簧静伸长量和工作行程等多重要求,从而有效控制主梁的涡振现象。本文提出的混合控制方案为类似工程中的涡振控制提供了有益参考,可为工程实践提供指导。

一种形状记忆合金半主动TMD系统的试验研究

针对调谐质量阻尼器(tuned mass damper,TMD)系统应用于轻型结构时易失调从而导致减振效果下降的问题,提出了一种新型形状记忆合金半主动TMD系统。该系统利用钢索悬吊质量块并承担其全部重量,使用有效截面为矩形的大尺寸镍钛形状记忆合金棒材,提供TMD系统水平面2个方向不同的抗弯刚度。为了研究该系统的半主动性能,进行了足尺形状记忆合金半主动TMD系统的自由振动试验,通过改变形状记忆合金的工作温度,研究了温度变化对TMD系统频率及阻尼比的影响。研究结果表明,控制形状记忆合金工作温度从-40~+80℃,TMD系统的频率随温度升高呈现升高趋势,而阻尼比随温度升高呈现下降趋势。将该新型形状记忆合金半主动TMD系统应用于受控结构中,一旦TMD失调,可以通过改变形状记忆合金的温度使其重新调谐。因此,设计的新型形状记忆合金TMD系统在轻型结构减振研究中具有一定的工程应用价值和前景。

考虑SSI效应时TMD的减震优化设计

土-结构相互作用(SSI)效应可能会对地震作用下调谐质量阻尼器(TMD)的有效性产生重要影响,因此本文研究了考虑SSI效应时TMD对高层建筑的抗震控制性能。针对一个质量分布均匀、层刚度随高度呈线性分布的40层benchmark结构,以结构顶层均方根位移最小为优化目标,采用改进粒子群算法对其在不同地基土条件以及地震波激励下的调谐质量阻尼器参数进行优化设计。优化结果表明,忽略SSI效应可能会造成地震激励下高层结构中TMD减震性能的不恰当估计,TMD的优化参数与地基土类型和地震波种类紧密相关。优化后的TMD可以有效降低结构顶层位移响应且不增加其峰值加速度,优化后的TMD耗散了绝大部分地震输入能量,并大大降低了结构能量。

移动荷载作用下悬浮隧道管体TMD减振分析及优化布置

为减小悬浮隧道管体在移动荷载作用下的动力响应,采用TMD作为振动控制措施并对减振效果进行了分析。将悬浮隧道管体简化为弹性地基梁,采用移动简谐力模拟汽车荷载,通过Morison方程计算管体振动过程中的流体附加惯性效应和阻尼效应,推导建立了移动荷载作用下管体-TMD系统振动控制方程组。采用Newmark-β法进行数值求解,分析了TMD对悬浮隧道管体的减振效果。针对悬浮隧道管体振动特征,提出采用分布式TMD的布置形式,并对移动速度、TMD阻尼比的影响进行了讨论。结论表明:TMD对移动简谐荷载作用下的悬浮隧道管体具有显著减振效果,最大位移减振率在50%以上。由于多阶模态参与振动,单一TMD的有效减振范围有限。在保持总质量不变的情况下,采用分布式TMD可以获得较好的整体减振效果。提高TMD质量比和降低移动荷载速度有助于提高TMD的减振效果。增大阻尼比会减弱TMD的效果,应综合考虑减振效果和工作空间的要求确定。

风、冰荷载联合作用下的海上单桩风机结构TMD减振控制模拟

寒冷地区海上风机结构受到复杂环境荷载作用,易出现振动安全性问题。文章以某6.45 MW海上单桩风机结构为例,施加风、冰荷载联合作用,对比分析多重调谐质量阻尼器(MTMD)系统减振前后的结构振动响应。结果表明:风、冰荷载会引起风机塔架的剧烈振动响应,最大位移响应出现在风机塔顶,最大加速度响应出现在结构二阶振型幅值点附近;除了前两阶频率,风、冰荷载还会激起塔架结构的更高阶响应;同时控制结构一二阶频率的MTMD方案可有效控制塔架位移、加速度和倾覆力矩响应,减振效果明显,但调谐质量阻尼器(TMD)装置存在频率敏感性,无法控制更高阶频率引起的结构振动响应。

大跨连廊结构的人致振动效应及TMD减振控制

针对某大跨度连廊结构的楼盖舒适度问题,建立了连廊的整体有限元模型,采用Ritz向量法对结构进行了模态分析,研究了大跨度连廊结构的振动特性并进行减振设计。根据不同的人群密度和行走频率,研究了四种人群荷载激励下楼盖的竖向振动情况,对比设置调频质量阻尼器(TMD)前后连廊结构的竖向加速度。结果表明,连廊的自振频率接近于人行频率,在人行荷载的激励下,连廊发生共振现象,形成较大振动,造成人体不适,故需控制振动;在连廊的合理位置设置TMD后,整体减振率达67.4%,楼盖振动满足人体舒适度要求,说明TMD起到了良好的减振作用。

Parameter Optimization of Tuned Mass Damper Inerter via Adaptive Harmony Search

Dynamic impacts such as wind and earthquakes cause loss of life and economic damage.To ensure safety against these effects,various measures have been taken from past to present and solutions have been developed using different technologies.Tall buildings are more susceptible to vibrations such as wind and earthquakes.Therefore,vibration control has become an important issue in civil engineering.This study optimizes tuned mass damper inerter(TMDI)using far-fault ground motion records.This study derives the optimum parameters of TMDI using the Adaptive Harmony Search algorithm.Structure displacement and total acceleration against earthquake load are analyzed to assess the performance of the TMDI system.The effect of the inerter when connected to different floors is observed,and the results are compared to the conventional tuned mass damper(TMD).It is indicated that the case of connecting the inerter force to the 5th floor gives better results.As a result,TMD and TMDI systems reduce the displacement by 21.87%and 25.45%,respectively,and the total acceleration by 25.45%and 19.59%,respectively.These percentage reductions indicated that the structure resilience against dynamic loads can be increased using control systems.

基于APDL风机塔筒MTMD系统参数敏感性分析

为了研究MTMD(多重调谐质量阻尼器)对风机塔筒振动控制时,各参数对振动控制效果的影响,基于ANSYS参数化设计语言(APDL)进行MTMD系统参数敏感性分析。首先在风机塔筒有限元模型的基础上,进行MTMD-塔筒耦合模型的建立,对塔筒进行谐响应分析,得到塔筒塔顶质量点位移频谱图。基于APDL改变TMD(调谐质量阻尼器)参数,进行“再建模-再分析”,以塔筒塔顶位移峰值为评价指标,对各参数进行敏感性分析。研究结果表明:单TMD系统减振效果随质量比、阻尼比增大而增大,且在频率比接近1时,减振效果达到最优;在MTMD在质量、刚度、阻尼参数发生偏移时,减振效果随TMD个数的增加而减弱,参数敏感性增强。

TMD对列车作用下大跨钢桁架桥的振动控制研究

南京长江大桥是连接我国南北的重要交通命脉,考虑到列车引起的振动对该桥危害较大,有必要采取有效措施对其进行振动控制。结合车桥动力方程,有限元分析时将列车经过大桥全过程的桥梁结构作为时变系统来考虑,基于ANSYS平台编制了动力时程响应分析程序。据此研究了调谐质量阻尼器(TMD)在该桥减振控制中的参数敏感性和控制效果,并对比分析了列车时速对减振效果的影响。结果表明,TMD在其刚度和阻尼系数取值合理时可达到最优控制效果;设计TMD对该桥列车致振动竖向加速度的控制效果明显,且在列车时速较高时减振效果更加显著。