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.

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.

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.

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.

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.

Development of piezoelectric energy-harvesting tuned mass damper

Tuned mass dampers（TMDs）are one of the most widely used devices to mitigate vibrations in structures.Usually,in conventional TMDs,viscous dampers convert the energy of vibration into heat.A new type of TMDs,called regenerative TMDs,has

Parametric control of structural responses using an optimal passive tuned mass damper under stationary Gaussian white noise excitations

In this study,the structural control strategy utilizing a passive tuned mass damper(TMD)system as a seismic damping device is outlined,highlighting the parametric optimization approach for displacement and acceleration control.The theory of stationary random processes and complex frequency response functions are explained and adopted.For the vibration control of an undamped structure,the optimal parameters of a TMD,such as the optimal tuning frequency and optimal damping ratio,to stationary Gaussian white noise acceleration are investigated by using a parametric optimization procedure.For damped structures,a numerical searching technique is used to obtain the optimal parameters of the TMD,and then the explicit formulae for these optimal parameters are derived through a sequence of curve-fitting schemes.Using these specified optimal parameters,several different controlled responses are examined,and then the displacement and acceleration based control effectiveness indices of the TMD are examined from the view point of RMS values.From the viewpoint of the RMS values of displacement and acceleration,the optimal TMDs adopted in this study shows clear performance improvements for the simplified model examined,and this means that the effective optimization of the TMD has a good potential as a customized target response-based structural strategy.

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.

Offshore Structural Control Considering Fluid Structure Interaction

Tuned Mass Damper （TMD） was applied to an offshore structure to control ocean wave-induced vibration, In the analysis of the dynamic response of the offshore structure, fluid-structure interaction is considered and the errors, which occur in the linearization of the interaction, are investigated. For the investigation of the performance of TMD in controlling the vibration, both regular waves with different periods and irregular waves with different significant wave heights are used. Based on the numerical analysis it is concluded that the fluid-structure interaction should be considered in the evaluation of the capability of TMD in vibration control of offshore structures.

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。

双重电磁谐振式调谐质量阻尼器的参数优化及对结构减振分析

利用电磁阻尼单元代替经典调谐质量阻尼器中的黏性阻尼单元,形成一种具有结构减振功能的新型电磁谐振式调谐质量阻尼器(electromagnetic shunt tuned mass damper,EMS-TMD)。为进一步提升阻尼器的减振性能和鲁棒性,设计了双重电磁谐振式调谐质量阻尼器(DEMS-TMD)减振方案。依据达朗伯定理,建立地震作用下DEMS-TMD与单自由度结构耦合振动系统的动力学模型。利用蒙特卡洛-模式搜索法数值优化方法,以主结构位移的动力放大系数最大值最小为目标函数,优化得到DEMS-TMD的结构频率比、电子频率比、电磁阻尼比和机电耦合系数的最优参数,为减振参数设计提供理论指导。通过频域和时域两种方法仿真分析了DEMSTMD对结构的减振性能。结果表明:在频域分析中,DEMS-TMD的主结构位移峰值和频响面积均优于传统并联双调谐质量阻尼器(double tuned mass damper,DTMD);在时域分析中,DEMS-TMD对结构位移、加速度峰值和均方根的减振性能均优于传统DTMD,有效地提高了对结构的减振效果。

风浪联合作用下分布式调谐质量阻尼器对海上半潜漂浮式风机的减振控制

海上半潜漂浮式风机在复杂深海环境下产生有害振动会威胁风机的安全性和耐久性,针对该问题并结合美国NREL的5 MW样机的漂浮平台几何结构构造,提出利用分布式调谐质量阻尼器(Tuned Mass Dampers,TMDs),即分别在漂浮平台的3根浮筒中布置TMD,形成等边三角形布置,对随机风浪联合作用下海上半潜漂浮式风机的平台纵摇振动进行控制。为了更好地描述分布式TMDs对海上半潜漂浮式风机的减振效果,基于拉格朗日方程和模态叠加法,对海上半潜漂浮式风机-TMDs耦合系统提出并建立了9自由度多体动力学模型。基于H_(∞)算法,即以平台纵摇频响函数的峰值为优化目标,对分布式TMDs的参数进行优化设计,优化设计中考虑了3个TMDs之间的耦合关系。对风机-TMDs耦合系统开展了风浪联合作用下的数值模拟,分析了分布式TMDs对平台纵摇响应的减振效果。结果表明:最优设计下的分布式TMDs对海上半潜漂浮式风机平台纵摇振动具有良好的减振性能;在三种不同工况的随机风浪荷载作用下,分布式TMDs对平台纵摇固有频率附近的功率谱密度曲线峰值减振率和标准差减振率能分别达到39%和52%以上。

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。

模块化建筑阵列多调谐质量阻尼系统的实现与减震研究

基于建筑模块化和悬挂楼板减震的原理提出了悬挂楼板模块体系(modularized suspended floors system,MSFS)。利用楼板作为质量块,组成分布阵列式多调谐质量阻尼器(distributed array multiple tuned mass dampers,d-array-MTMDs)系统。通过输入32条远场和近场地震动记录进行时程分析,对平均调谐频率比η、调谐频带宽度系数β、调谐阻尼比ζ_(T)、TMD数量n以及主结构层数N,共5个参数展开研究。结果表明:d-array-MTMDs的减震效果优于普通MTMDs系统;ζ_(T)对系统减震性能影响较小,当η为0.7~1.0、β为2.0时,系统具有更好的减震效果;当n大于某阈值时,系统的减震效果趋于稳定,阈值与η线性正相关,与ζ_(T)非线性负相关。随着模块建筑层数的增加,系统也能维持较好的减震效果。

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。

调谐惯质阻尼器动力试验和参数识别

研发了一种新型调谐惯质阻尼器(TVMD)装置,该装置分别采用电涡流与金属弹簧作为TVMD的阻尼元件与弹簧元件.首先,对该TVMD装置进行动力试验,研究其动力特性.然后,提出4种基于试验数据识别TVMD参数的方法,即峰值点拟合法、滞回曲线拟合法、时程拟合法和传递函数拟合法.动力试验结果表明:TVMD具有惯性质量放大效应和阻尼增益效应;弹簧元件和惯容元件均表现出理想的线性特性,而阻尼元件由于电涡流阻尼固有属性和TVMD装置中存在的摩擦,表现出非线性特性.参数识别结果表明:4种方法均能合理确定TVMD参数,其中,传递函数拟合法能提供用于调谐设计的等效阻尼系数,而其他3种方法能识别非线性阻尼模型的参数;滞回曲线拟合法和时程拟合法具有更高的参数识别精度,而峰值点拟合法和传递函数拟合法具有更高的计算效率.

变截面钢桁梁人行桥人致振动及振动控制研究

为研究变截面钢桁梁人行桥人致振动舒适度及调谐质量阻尼器(tuned mass damper,TMD)的减振效果,以某京杭大运河钢桁梁人行桥为研究对象,采用有限元模拟和现场实测2种方式,研究钢桁梁人行桥人致振动响应。基于有限元模型,分析未安装TMD之前的桥梁振动响应,确定行人舒适度水平,讨论行人密度、阻尼比和人群激励频率等参数对其的影响,以此给出TMD设计参数,并分析了TMD质量比对减振效果的影响;对安装TMD之后的人行桥进行了现场实测,并在实测基础上,采用加速度时程和频谱分析对相应工况进行桥梁人致振动响应研究。研究结果表明:安装TMD之前,该桥加速度响应超过规范限值,需要考虑人致振动的影响;其加速度响应在一定范围内随着行人密度增长而增大,随着阻尼比的增大而减小;当行人步频接近桥梁某阶振动频率时,振动响应明显增大;安装TMD之后,该桥实测的人致振动响应有所降低,其响应规律与模拟结果较为一致。文中的研究成果可为变截面钢桁梁人行桥人致振动研究提供理论支持。

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。

随机激励下带滞变阻尼的调谐质量阻尼器减振性能研究

近年来,阻尼力与位移呈线性关系的新型调谐质量阻尼器(Tuned mass damper, TMD)相继出现,其参数分析优化原理大部分属于动力数值分析缺乏理论参数优化指导。该文对白噪声作用下具有上述特性的TMD,即滞变阻尼调谐质量阻尼器(Hysteretic damping tuned mass damper, HD-TMD)进行减振优化研究。总结了HD-TMD的力学机理并推导出相应的结构-HD-TMD系统运动方程;提出适用于HD-TMD的H_(2)优化和性能平衡设计,并通过数值拟合技术得到了最优参数公式和基于容忍度的性能平衡设计流程;以真实可用的变摩擦摆式调谐质量阻尼器(VFP-TMD)为HD-TMD的实际算例,检验所提出的优化方法对风振激励的减振性能影响。结果表明:H_(2)优化和性能平衡设计下的HD-TMD可以提供略优于传统黏滞阻尼TMD的控制效果。H_(2)优化的最优参数能使HD-TMD发挥最大的潜能从而实现最好的减振率,但面临VFP-TMD行程过大导致的摆动非线性问题。性能平衡设计下的最优参数可以控制VFP-TMD行程在线性范围内,同时发挥出良好且稳定的减振控制效果实现双赢。与最优参数公式结果相比,性能平衡设计的峰值减振率和均方差峰值减振率仅损失3.19%和0.74%。