Study on adaptive‐passive eddy current pendulum tuned mass damper for wind‐induced vibration control

Tuned mass dampers (TMDs) are used to control wind‐excited responses of high‐rise building as traditional vibration control devices. A TMD will have an excellent control effect when it is well tuned. However, a traditional passive TMD is sensitive to the frequency deviation; the mistuning in frequency and damping ratio both will decrease its control effect. In the previous research, an adaptive‐passive variable pendulum TMD (APVP‐TMD) is proposed, which can identify the TMD optimal frequency and retune itself through varying its pendulum length. However, it is found that the frequency variation will change the TMD damping ratio, and an unreasonable damping ratio will lead to a decrement in the robustness of a TMD. In this study, an adaptive‐passive eddy current pendulum TMD (APEC‐PTMD) is presented, which can retune the frequency through varying the pendulum length, and retune the damping ratio through adjusting the air gap between permanent magnets and conductive plates. An adjustable eddy current pendulum TMD (PTMD) is tested, and then, a single‐degree‐of‐freedom (SDOF) primary model with an APEC‐PTMD is built, and functions of frequency and damping ratio retuning are verified. The 76‐story wind‐sensitive benchmark model is proposed in the case study. The original model without uncertainty and ±15% stiffness uncertainty models are considered, and response control effects of different controllers are compared. Results show that because the APEC‐PTMD can both retune its frequency and damping ratio; it is more robust and effective than a passive TMD. It is also found that the APEC‐PTMD has a similar control effect with the active TMD, with little power consumption and better stability.     

调谐质量阻尼器和调谐型颗粒阻尼器减震性能对比研究

基于5层钢框架模型,通过试验对比了在地震激励下调谐质量阻尼器和调谐型颗粒阻尼器的减震性能,并探究了频率失调等因素的影响。通过数值模拟实现了两种阻尼器的优化设计,以考察充分发挥其性能的工况下,两种阻尼器的减震效果以及阻尼器相对位移行程的对比。研究表明：在频率调谐时,调谐质量阻尼器和调谐型颗粒阻尼器均能显著降低主体结构位移和加速度响应,调谐型颗粒阻尼器的减震效果更好,具有一定的减震优势,并且调谐型颗粒阻尼器的相对位移行程更小、减震频带更宽;当两者均为最优设计时,减震效果相当,但是最优化调谐型颗粒阻尼器系统的阻尼器与主体结构之间的相对位移更小,可降低相对位移幅值24.5%,并且具有更好的鲁棒性。     

半主动电涡流单摆式调谐质量阻尼器减震性能研究

为了提高传统的调谐质量阻尼器（TMD）对建筑结构的减震效果,提出了一种可实时调整频率和阻尼的半主动电涡流单摆式调谐质量阻尼器(SAEC-PTMD)。由Hilbert-Huang变换(HHT)识别结构的瞬时频率,通过基于HHT的控制算法实时调节SAEC-PTMD的摆长进行频率的调节。研究并拟合了电涡流有效阻尼系数与磁导间距之间的关系,通过基于线性二次型高斯(LQG)的控制算法实时调节磁导间距,以实时调节阻尼系数。为了验证SAEC-PTMD对建筑结构的减震效果,对一单自由度结构模型在地震激励下的震动响应进行数值模拟。数值模拟中,采用一经优化设计的被动TMD (PTMD)作为对比,并考虑由主结构的累积损伤引起自身频率下降而造成PTMD的失调效应。以主结构的加速度和位移时程峰值、整体均方根值及其加速度和位移反应谱作为评价指标,评估了SAEC-PTMD在结构发生损伤前后对PTMD的改良效果。数值模拟结果表明,在结构发生损伤前后,SAEC-PTMD均比经优化设计的PTMD具有更好的减震效果。     

Study on self‐adjustable variable pendulum tuned mass damper

Pendulum tuned mass damper (PTMD) is usually used to control the horizontal vibration of a tall building. However, traditional PTMD is highly sensitive to frequency deviation and difficult to adjust its frequency. In order to improve this problem of traditional PTMD and protect a tall building more effectively, a novel PTMD, called self‐adjustable variable pendulum tuned mass damper (SAVP‐TMD), is proposed in this paper. On the basis of the acceleration ratio between TMD and primary structure, the SAVP‐TMD can retune itself by varying the length of the pendulum according to the improved acceleration ratio‐based adjustment algorithm. PTMD and primary structural accelerations are obtained from two accelerometers respectively, and the acceleration ratio is calculated in a microcontroller, then, the stepper motor will adjust the pendulum under the guidance of the microcontroller under a specific harmonic excitation. The improved acceleration ratio‐based adjustment algorithm is proposed and compared to solve the nonconvergent retuning problem. The SAVP‐TMD can be regarded as a passive damper including a frequency adjustment device. A single‐degree‐of‐freedom structure model is used to verify the effectiveness of SAVP‐TMD through both experimental study and numerical simulation. In order to further verify the effect of SAVP‐TMD in the MDOF structure, a five‐storey structure coupled with an SAVP‐TMD is proposed as a case study. The results of experiment, simulation, and case study all show that SAVP‐TMD can retune itself to the primary structural dominant frequency robustly, and the retuned PTMD has a better vibration control effect than the mistuned one.     

调频减振系统和黏滞阻尼系统在超高层结构中风振控制性能的对比研究

超高层建筑中常用的风振控制措施主要包括调频减振系统和黏滞阻尼系统.系统地阐述了两种方案的基本原理、工程适用性以及参数取值,并结合实际项目较为全面地对比了其抗风性能.虽然调频减振系统在建筑功能的适应度上和施工可实施性上都存在一定的不足,但作为结构风振控制措施仍不失为一种可取方案.黏滞阻尼系统不但可以提升结构在风荷载下的舒...     

Coupled‐two‐beam discrete model for dynamic analysis of tall buildings with tuned mass dampers including soil–structure interaction

An equivalent coupled‐two‐beam discrete model is developed for time‐domain dynamic analysis of high‐rise buildings with flexible base and carrying any number of tuned mass dampers (TMDs). The equivalent model consists of a flexural cantilever beam and a shear cantilever beam connected in parallel by a finite number of axially rigid members that allows the consideration of intermediate modes of lateral deformation. The equivalent model is applied to a shear wall–frame building located in the Valley of Mexico, where the effects of soil–structure interaction (SSI) are important. The effects of SSI and TMDs on the dynamic properties of the shear wall–frame building are shown considering four types of soil (hard rock, dense soil, stiff soil, and soft soil) and two passive damping systems: a single TMD on its top (1‐TMD) and five uniformly distributed TMDs (5‐TMD). The results showed a great effectiveness of the TMDs to reduce the lateral seismic response and along‐wind response of the shear wall–frame building for all types of soils. Generally speaking, the dynamic response increases as the flexibility of the foundation increases.     

采用颗粒调谐质量阻尼器的钢框架结构振动台试验研究

通过附加和不附加颗粒调谐质量阻尼器的5层钢框架振动台试验,研究其在实际地震波以及上海人工波激励下的减震效果。通过调整不同悬挂长度（频率比）、质量比、颗粒到阻尼器壁净距等参数,分析阻尼器参数对其减震效果的影响。试验结果表明：不同地震作用下该类阻尼器均能达到较好的减震效果,其中上海人工波的减震效果最好;对于多层钢框架结构,阻尼器能够有效控制第1振型的振动,但是对于高阶振型的控制作用无法保证;当阻尼器频率与主体结构基频相同时,能够达到最优减震效果,而当二者频率不同时,依然有一定的减震效果,说明其具有一定的鲁棒性;在合适的质量比（0.66%）下,阻尼器能够达到最佳减震效果;当颗粒到容器内壁净距为1.6D~3.6D时,可使阻尼器响应最小,且减震效果较好。     

Optimizing parameters of tuned mass damper subjected to critical earthquake

Tuned mass damper (TMD) has been proposed as one of the vibration control methods for rehabilitation of buildings. Because the parameters of TMD can significantly affect the seismic performance of structures, many researches focused on finding the optimum parameters. Because earthquakes are random phenomena and future earthquakes in comparison with past earthquakes may be more destructive, the optimum design of TMD subjected to selected earthquakes can be nonconservative. Hence, the main contribution of this paper is to present the optimal design of TMD for the seismic vibration control of a structure subjected to a critical earthquake that produces the most severe response of a structure. In order to achieve this purpose, the parameters of TMD are optimized through minimizing the maximum displacement of the roof. First, three optimization methods are used to obtain the optimal parameters of TMD for a 10‐story shear building subjected to the critical earthquakes. Finally, the responses of the controlled and uncontrolled buildings such as the roof displacement, strokes, transfer function, and different forms of energy are compared. Results show that the optimum designs of TMD not only effectively reduce the roof displacement but also improve the seismic performance of the building.     

Shaking table model test and FE analysis of a reinforced concrete mega‐frame structure with tuned mass dampers

To study the damage characteristics and to evaluate the overall seismic performance of reinforced concrete mega‐frame structures, a shaking table test of a 1/25 scaled model with a rooftop tuned mass damper (TMD) is performed. The maximum deformation and acceleration responses are measured. The dynamic behavior and the damping effect with and without TMD are compared. The results indicate that the mega‐frame structure has excellent seismic performance and the TMD device has a significant vibration reduction effect. A finite element (FE) model simulating the scaled model is also developed, and the numerical and experimental results are compared to provide a better understanding of the overall structural behavior in particular those related to the dynamic characteristics and damping effect. Upon verification of the FE model, other important structural behavior can also be predicted by the FE analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

附加PTMD风力发电机结构减振控制试验研究

通过开展附加颗粒调谐质量阻尼器(particle tuned mass damper, PTMD)风力发电机结构模型的自由振动试验和振动台试验,研究PTMD自身参数对其减振性能的影响规律,检验PTMD用于降低风力发电机结构不利振动的合理性与有效性,揭示随机激励下耦合系统的工作机理。借助自由振动试验研究了设计参数对PTMD减振性能的影响规律,初步确定了系统的参数配置。同时,通过地震波激励工况、风荷载激励工况和风-地震耦合荷载激励工况对风力发电机结构使用PTMD进行振动控制的合理性与有效性进行了检验,进一步揭示随机激励下耦合系统的减振机理。试验结果表明：颗粒-腔体质量比和频率比参数分别取值0.27和0.97时PTMD表现出较好的减振性能;3种随机激励下PTMD能够有效抑制风力发电机结构的动力响应,其中,El Centro波作用下,PTMD对结构顶部加速度和位移峰值响应的控制效果分别为5.52%和7.73%,而对均方根响应的控制效果则高达33.3%和32.08%。由此可见,PTMD对均方根响应的控制效果优于峰值响应。对比传统调谐质量阻尼器(TMD)结果可知,经合理设计的PTMD具有更佳的减振...     

Hybrid simulation of a tall building with a double‐decker tuned sloshing damper system under wind loads

This study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently referred to as hybrid testing, to validate the effectiveness of a double‐decker tuned sloshing damper (TSD) system with screens applied to a recently constructed tall building. The HIL simulation facilitates a performance analysis of a combined structure‐damper system in which the nonlinear behavior of liquid motion in a TSD is physically modeled, whereas a building system under wind loads that behaves linearly is embedded virtually utilizing a computer model. The scaled model of the TSD is composed of a computer‐controlled system with a shaking table, sensors, and a real‐time communication link. The virtual building system on the computer communicates in real time with the hardware, that is, the physical model of TSD to evaluate on‐the‐fly the performance of a combined building‐TSD system. External excitation including random loading characteristics of winds, waves, or earthquakes can be implemented in HIL to observe the dynamics of the building‐damper system under a host of loading scenarios. An example of a recently completed tall reinforced concrete building with multiple TSDs placed side by side in double‐decker configuration under a suite of external loads and the proposed damping estimation procedure to evaluate the amount of auxiliary damping with TSD for ensuring the TSD design is presented. It examines the habitability of the building in winds and evaluates the effectiveness of the TSD system as well as the efficacy of the first HIL simulation for an actual tall building‐TSD system equipped with screens inside.     

Experimental parametric study on wind‐induced vibration control of particle tuned mass damper on a benchmark high‐rise building

A particle tuned mass damper system is an integration of tuned mass damper and particle damper. The damping performance of such device is investigated by an aero‐elastic wind tunnel test on a benchmark high‐rise building. The robustness of the system is studied by comparing the damping performance to that of a traditional tuned mass damper, and the results show that the damper has excellent and steady wind‐induced vibration control effects. Meanwhile, the parameters (filling ratio, mass ratio, and mass ratio of the container to particles), which have great influence on the vibration reduction performance of the system, are also analyzed, and it is found that the particles filling ratio plays the most important role in deciding the damping effects of the dampers. There exists an optimum filling ratio and mass ratios in which the damper can reach the best damping state. Proper parameter selections can greatly improve the damping performance.     

Effect of tuned mass damper on the interaction of a quarter car model with a damaged bridge

This paper considers the effects of a tuned mass damper (TMD) on damaged bridge–accelerating quarter car vehicle interaction. The damage of the bridge is considered to be an open crack. The incorporation of a TMD to control the vibration response of the bridge and the quarter car vehicle model has been investigated from different aspects. A simplified form for the tuning ratio of the TMD is proposed. The vibration mitigation of the peak displacement, velocity and acceleration of the damaged bridge and the accelerating quarter car vehicle model using such a tuning is observed, along with the effects of possible detuning of the TMD due to the progressive deterioration of the bridge. A detailed parametric study is performed on the system with the TMD, considering the effects of quarter car vehicle model velocity, acceleration and the severity of the damage of the bridge.     

A combined tuned damper and an optimal design method for wind‐induced vibration control for super tall buildings

The wind‐induced vibrations of super tall buildings become excessive due to strong wind loads, super building height and high flexibility. Tuned mass dampers (TMDs) and tuned liquid column dampers (TLCDs) have been widely used to control vibrations for actual super tall buildings for decades. To fully use both the economic advantage of the TLCD system and the high efficiency of the TMD system, an innovative supplemental damping system including both TLCD and TMD and called combined tuned damper (CTD), which can substantially decrease the cost of the damper, was proposed to control the wind‐induced vibrations of tall buildings. The governing equations are generated for the motion of both the primary structure and the CTD and solved to anticipate the dynamic response of the CTD‐structure system. Moreover, an optimal design method of human comfort performance is proposed, in which the life cycle cost of the damper‐structure system is considered as the quantitative index of the performance. The life cycle cost includes the initial cost, the maintenance cost and the failure cost. The failure cost can be calculated using the vibration‐sensation rate model, which is based on the Japanese code AIJES‐V001‐2004. Copyright © 2016 John Wiley & Sons, Ltd.     

Improving the wind‐induced human comfort of the Beijing Olympic Tower by a double‐stage pendulum tuned mass damper

With five sub towers and a maximum height of 246.8 m, the Beijing Olympic Tower (BOT) is a landmark of Beijing. The complex structural properties and slenderness of the BOT render it prone to wind loading. As far as the wind‐induced performance of this structure is concerned, this paper thus aims at a tuned mass damper‐based mitigation system for controlling the wind‐induced acceleration response of the BOT. To this end, the three‐dimensional wind loading of various wind directions are simulated based on the fluctuating wind force obtained by the wind tunnel test, by which the wind‐induced vibration is evaluated in the time domain by using the finite element model. A double‐stage pendulum tuned mass damper (DPTMD), which is capable of controlling the long period dynamic response and requires only a limited space of installation, is optimally designed at the upper part of the tower. Finally, the wind‐induced response of the structure with and without DPTMD is compared with respect to various wind directions and in both the time and frequency domains. The comparative results show that the wind‐induced accelerations atop the tower with the wind directions of 45, 135, 225, and 315° are larger than those with the other directions. The DPTMD significantly reduces the wind‐induced response by the maximum acceleration reduction ratio of 30.05%. Moreover, it is revealed that the control effect varies noticeably for the five sub towers, depending on the connection rigidity between Tower1 and each sub tower.     

Large‐scale shaking table test on pile‐soil‐structure interaction on soft soils

The two large‐scale shaking table tests of tall buildings on soft soils in pile group foundations are performed to capture the effect of the seismic pile‐soil‐structure interaction (PSSI) on the dynamic responses of the pile, soil, and structure. The two different model conditions are observed, including a fixed‐base structure and a structure supported by 3‐by‐3 pile group foundation in soft soil, representing the situations excluding the soil‐structure interaction (SSI) and considering the SSI, respectively. In the tests, the superstructure is a tall building with 12‐story reinforced concrete frame. The pile‐soil‐structure system rests in a shear laminar soil container, which is designed to minimize the boundary effects during shaking table tests. The two models are subjected to various intensity seismic excitations of Shanghai bedrock waves, 1995 Kobe earthquake, and 1999 Chi‐Chi earthquake events. According to the experimental and analytical results, SSI systems have longer natural periods than the fixed‐base structure. In addition, soft soil has amplification effect under smaller seismic excitations and isolation effects under larger earthquake intensities. The strain amplitude at the top of pile is large, and the strain at the middle and tip is relatively small. Whereas the contact pressure is small at the top of pile and large at the middle and tip. From the dynamic responses of the superstructure, it is found that the PSSI amplifies the peak displacements and interstory drifts of the structures supported by pile group foundations by comparing with the fixed‐base structure. Whereas the peak acceleration and interstory shear force of the structure are reduced considering seismic PSSI. The results show that the seismic SSI is not always favorable, however, it may increase certain dynamic responses of the structure. Consequently, the seismic SSI should be considered reasonably, providing insight towards the rational seismic design of buildings rested on soft soils.     

Performance–cost optimization of tuned mass damper under low‐moderate seismic actions

In this paper, a multi‐objective optimization of a single tuned mass damper is proposed at the aim to control vibrations induced in building structures under low‐moderate earthquakes. The optimum design is carried out by considering both economic and performance criteria. The cost of the device is the economic objective that is assumed directly related to its mechanical parameters. At the aim to control the damage level and the behaviour of components and equipment, the ratio between the absolute accelerations of the protected structure and the unprotected one is assumed as the device performance. A multi‐objective optimization is then formulated, and Pareto optimum solutions are achieved by the Non‐dominated Sorting Genetic Algorithm in its second version. Finally, a sensitivity analysis of the optimum solution with respect to some input data is carried out. Copyright © 2016 John Wiley & Sons, Ltd.     

Mechanism and optimum design of shared tuned mass damper for twin‐tower structures connected at the top by an isolated corridor

The concept of shared tuned mass damper (STMD) for twin towers linked by a sky corridor using flexible joints is proposed in this paper. The analytical expressions of the transform functions and random earthquake responses of the flexibly connected structures are derived using a three‐degrees‐of‐freedom model system. The seismic reduction mechanism of the STMD is revealed using comparative analysis between the structures with STMD and those connected using a viscoelastic damper. The effect of the nondimensional parameters such as the frequency ratio of the two primary structures, mass ratio, tuning frequency ratio of the corridor, and damping ratio of the passive control devices on the structural seismic response is investigated. Optimum parametric analysis is performed using the principle of minimizing the displacements of both towers, and the optimal parameter formulas are established. Numerical analysis is conducted to verify the control effectiveness of the connected multi‐degree‐of‐freedom system subjected to the El Centro earthquake ground motion. The results show that the earthquake responses of the towers can be effectively reduced if the parameters of the flexible connecting elements are appropriately selected for a certain corridor mass. Moreover, a remarkable seismic reduction effect can be achieved if the towers have similar dynamic properties.     

Wind tunnel study of the across-wind response of a slender tower with a nonlinear tuned mass damper

The effectiveness of a class of nonlinear tuned mass dampers (TMDs) in suppressing across-wind structure oscillations was examined through a wind tunnel test. The nonlinear TMD employed a wire rope spring to replace both the spring and the damper required in a typical system. First, a single degree of freedom aeroelastic stick model of a slender structure with a square cross-section was tested under different levels of damping. The measurements obtained from the tests were used to determine the root-mean-square (RMS) of the lift coefficient and other aerodynamic parameters. In the second phase of testing, the nonlinear TMD system was attached near the tip of the aeroelastic model. The response reduction achieved by adding the TMD was considerable and was quantitatively expressed in terms of an equivalent viscous damping. A comparison between the nonlinear TMD and an equivalent optimized linear TMD was made. Probability-based procedures were developed to estimate the equivalent damping provided by the nonlinear TMD. The estimated damping was compared with that obtained experimentally to evaluate the accuracy of the prediction method.     

齿轮齿条式电涡流阻尼器的力学性能研究

为开发性能良好的新型耗能装置,采用齿条齿轮和电涡流阻尼技术,提出一种新型的齿轮齿条式电涡流阻尼器(eddy current damping-rack and gear damper,简称ECD-RGD),并对其力学性能进行有限元仿真和试验研究。首先,介绍ECD-RGD的构造和运动分解,并设计制作ECD-RGD样机;然后,考虑两个加载角度研究ECD-RGD的表观质量和阻尼性能;最后,对ECD-RGD的滞回性能进行试验研究。结果表明：ECD-RGD是一种实现表观质量惯性力和电涡流阻尼力并联的新型阻尼器,可将结构振动的随机方向分解为确定的相互垂直的两方向加以控制;表观质量的理论结果与试验结果、电涡流阻尼力的仿真结果与试验结果总体吻合均较好;样机试验性能稳定,齿轮齿条式电涡流阻尼器具有可应用性。