Dissertations / Theses on the topic 'Tuned mass control'
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Alhujaili, Fahad Abdulrahman. "Semi-Active Control of Air-Suspended Tuned Mass Dampers." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1354480214.
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Chey, Min Ho. "Passive and Semi-Active Tuned Mass Damper Building Systems." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2007. http://hdl.handle.net/10092/3431.
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This thesis explores next generation passive and semi-active tuned mass damper (PTMD and SATMD) building systems for reducing the seismic response of tall structures and mitigating damage. The proposed structural configuration separates the upper storey(s) of a structure to act as the 'tuned' mass, either passively or semi-actively. In the view point of traditional TMD system theory, this alternative approach avoids adding excessive redundant mass that is rarely used. In particular, it is proposed to replace the passive spring damper system with a semi-active resetable device based system (SATMD). This semi-active approach uses feedback control to alter or manipulate the reaction forces, effectively re-tuning the system depending on the structural response. In this trade-off parametric study, the efficacy of spreading stiffness between resetable devices and rubber bearings is illustrated. Spectral analysis of simplified 2-DOF model explores the efficacy of these modified structural control systems and the general validity of the optimal derived parameters is demonstrated. The end result of the spectral analysis is an optimally-based initial design approach that fits into accepted design methods. Realistic suites of earthquake ground motion records, representing seismic excitations of specific return period probability, are utilised, with lognormal statistical analysis used to represent the response distribution. This probabilistic approach avoids bias toward any particular type of ground motion or frequency content. Statistical analysis of the performance over these suites thus better indicates the true overall efficacy of the PTMD and SATMD building systems considered. Several cases of the segregated multi-storey TMD building structures utilising passive devices (PTMD) and semi-active resetable devices (SATMD) are described and analysed. The SATMD building systems show significant promise for applications of structural control, particularly for cases where extra storeys might be added during retrofit, redevelopment or upgrade. The SATMD approach offers advantages over PTMD building systems in the consistent response reductions seen over a broad range of structural natural frequencies. Using an array of performance metrics the overall structural performance is examined without the typically narrow focus found in other studies. Performance comparisons are based on statistically calculated storey/structural hysteretic energy and storey/structural damage demands, as well as conventional structural response performance indices. Overall, this research presents a methodology for designing SATMD building systems, highlighting the adaptable structural configuration and the performance obtained. Thus, there is good potential for SATMD building systems, especially in retrofit where lack of space constrains some future urban development to expand upward. Finally, the approach presented offers an insight into how rethinking typical solutions with new technology can offer dramatic improvements that might not otherwise be expected or obtainable.
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Gutierrez, Soto Mariantonieta. "INVESTIGATION OF PASSIVE CONTROL OF IRREGULAR BUILDING STRUCTURES USING BIDIRECTIONAL TUNED MASS DAMPER." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354596462.
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Liedes, T. (Toni). "Improving the performance of the semi-active tuned mass damper." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514291258.
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Abstract
The tuned mass damper (TMD) is a well-known and approved concept for resonance vibration control. However, as a fully passive device, the traditional TMD has a limited operating band and rather poor robustness against parameter variations. To overcome these weaknesses, a semi-active control can be applied to TMD. As a result, a more effective and flexible device can be attained. In theory, the application of the semi-active scheme is straightforward and the gain in performance is considerable. In practice, however, the non-idealities associated with actuators and control systems degrade the performance.
In this thesis, the dynamic behaviour of a semi-active TMD with groundhook control was studied both numerically and experimentally. The semi-active scheme studied is based on groundhook control and a dry-friction damper is used as an actuator in rapid damping modulation. The performance of the semi-active TMD was evaluated in terms of two performance indices which are calculated from the normalised displacement response in the frequency domain. Also, parametric studies were conducted to find out how the different parameters influence the system performance. It is shown that the non-idealities in the semi-active damper have a significant influence on the performance of a groundhook controlled semi-active TMD.
On the basis of simulations, a new parameterised semi-active control method was developed. The method is treated as a generalised groundhook control, and it involves a parameter through which the dynamic behaviour of a semi-active TMD can be affected both online and offline. The new method does not require an actuator model. The method developed opens the way for effective use of a non-ideal semi-active actuator, thus ensuring the good performance of the semi-active TMD. Also, the semi-active TMD’s sensitivity for certain parameter variation decreases considerably.
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Rottmann, Cheryl E. "The use of tuned mass dampers to control annoying floor vibrations." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-09182008-063455/.
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Nunziatini, Gioele. "Structural motion control: typologies and applications of tuned mass damper systems." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4249/.
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Ritchey, John Kenneth. "Application of Magneto-Rheological Dampers in Tuned Mass Dampers for Floor Vibration Control." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35287.
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The purpose of this research is to establish the effectiveness of tuned-mass-dampers (TMD) using semi-active magneto-rheological (MR) dampers to mitigate annoying floor vibrations. Annoying floor vibration is becoming more common in today's building structures since building materials have become stronger and lighter; the advent of computers has resulted in "paperless" offices; and the use of floors for rhythmic activities, such as aerobics and concerts, is more common. Analytical and experimental studies were conducted to provide an understanding of the effects of incorporating the semi-active-TMD as a remedy to annoying floor vibration.
A pendulum tuned mass damper (PTMD) in which the tuning parameters could independently be varied was used. Closed form solutions for the response of the floor using passive dampers were developed. In addition, a numerical integration technique was used to solve the equations of motion where semi-active dampers are utilized. The optimum design parameters of PTMDs using passive and semi-active dampers were found using an optimization routine. Performances of the PTMD in reducing the floor vibration level at the optimum and when subjected to off-tuning of design parameters using passive and semi-active dampers were compared.
To validate the results obtained in the analytical investigation, an experimental study was conducted using an 8 ft x 30 ft laboratory floor and a commercial PTMD. Comparative studies of the effectiveness of the PTMD in reducing floor vibrations using semi-active and passive dampers were conducted.
Master of Science
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Eltaeb, Mohamed A. "Active Control of Pendulum Tuned Mass Dampers for Tall Buildings Subject to Wind Load." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton150343994189116.
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Gong, Zheng Li. "Passive motion control of super tall buildings : tuned mass and viscous dampers in Taipei 101." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/51575.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.Includes bibliographical references (leaves 50-51).
As tall buildings keep becoming taller, they become more susceptible to dynamic excitations such as wind and seismic excitations. One way to reduce structural vibration under dynamic excitations is by placing damping devices in the buildings. In this thesis, the design concept, design procedure and some current applications of tuned mass and viscous dampers are discussed. Taipei101 was used as an example to compare the performance of the two damping schemes. It was modeled in a two-dimensional scheme in SAP2000 and a TMD was placed on its top to study its effect on the structural response due to wind and seismic excitations and confirm with the actual results. A sensitivity study was then performed to study the effect of varying the mass ratio on the structural response. A second TMD was then placed at the location where the maximum deflection occurs for the second mode to evaluate its effectiveness in reducing structural response. Finally, twelve viscous dampers were placed in the model to study their effects on the structural response. Time-history and steady-state analysis in SAP2000 were used for the wind and seismic analyses.
M.Eng.
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Marian, Laurentiu. "The tuned mass damper inerter for passive vibration control and energy harvesting in dynamically excited structural systems." Thesis, City University London, 2016. http://openaccess.city.ac.uk/14884/.
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A novel passive vibration control configuration, namely the Tuned-Mass-Damper-Inerter (TMDI) is proposed in this work. The TMDI combines the “inerter”, a mechanical two-terminal flywheel device developing resisting forces proportional to the relative acceleration of its terminals, with the well-known and widely used in various passive vibration control applications Tuned-Mass-damper (TMD). Introduced as a generalization of the TMD, the TMDI takes advantage of the “mass amplification effect” of the inerter to achieve enhanced performance compared to the classical TMD. For linear harmonically excited primary systems, analytical closed-form expressions are derived for optimal TMDI design/tuning parameters using the well-established and widely applied for the case of the classical TMD semi-empirical fixed-point theory. It is shown that for the same attached mass the TMDI system is more effective than the classical TMD to suppress vibrations close to the natural frequency of the uncontrolled primary system, while it is more robust to de-tuning effects. Moreover, it is analytically shown that optimally designed TMDI outperforms the classical TMD in minimizing the displacement variance of undamped linear single-degree-of-freedom (SDOF) white-noise excited primary systems. For this particular case, optimal TMDI parameters are derived in closed-form as functions of the additional oscillating mass and the inerter constant. Furthermore, pertinent numerical data are furnished, derived by means of a numerical optimization procedure, for classically damped mechanical cascaded chain-like primary systems base excited by stationary colored noise. This exemplifies the effectiveness of the TMDI over the classical TMD to suppress the fundamental mode of vibration for linear MDOF structures. It is concluded that the incorporation of the inerter in the proposed TMDI configuration can either replace part of the TMD vibrating mass to achieve lightweight passive vibration control solutions, or improve the performance of the classical TMD for a given TMD mass. The TMDI is further applied for passive vibration control of seismically excited building structures. An input non-stationary stochastic process compatible with the elastic design spectrum of the European aseismic code provisions (EC8) is assumed. The effectiveness of the proposed TMDI configuration over the classical TMD is assessed by performing response history analyses for an ensemble of EC8 spectrum compatible field recorded strong ground motions. The optimally tuned TMDI solution achieves considerable reduction of the peak average top floor displacement and peak average top floor accelerations of the considered primary structures compared to the one achieved by the optimally designed classical TMD, assuming the same additional mass in both cases. Furthermore, the TMDI configuration achieves significant reduction in the maximum displacement of the additional oscillating mass. In this study, the primary structures are assumed to behave linearly in alignment with current trends in performance based requirements for minimally damaged structures protected by passive control devices. Furthermore, optimally designed TMDI is applied for vibration suppression and energy harvesting via an electromagnetic device which transforms the mechanical kinetic energy into electrical energy. Unlike the case of traditional energy harvesting enabled TMD systems, the amount of available energy to be harvested by the herein proposed TMDI-based harvester is leveraged by changing the intensity of the mass amplification effect of the inerter, through mechanical gearing, without changing the weight of the TMDI system. Therefore, the inclusion of the inerter adds a “degree of freedom” or a design parameter to the classical TMD-based harvesters allowing to control the trade-off between vibration suppression and energy harvesting in a more flexible manner. Overall, the herein reported numerical data and analytical work provide evidence that the TMDI offers a novel promising solution for passive vibration control and energy harvesting. Most importantly, it opens several new research paths involving numerical/parametric work, as well as, prototyping, experimental testing and field deployment.
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Koo, Jeong-Hoi. "Using Magneto-Rheological Dampers in Semiactive Tuned Vibration Absorbers to Control Structural Vibrations." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/29023.
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Since their invention in the early 1900s, Tuned Vibration Absorbers (TVAs) have shown to be effective in suppressing vibrations of machines and structures. A vibration absorber is a vibratory subsystem attached to a primary system. It normally consists of a mass, a spring, and a damper. Mounted to the primary system, a TVA counteracts the motions of the primary system, "absorbing" the primary structure's vibrations. A conventional passive TVA, however, is only effective when it is tuned properly, hence, the name "tuned" vibration absorber. In many practical applications, inevitable off-tuning (or mistuning) of a TVA occurs because of the system's operating conditions or parameter changes over time. For example, the mass in a building floor could change by moving furnishings, people gathering, etc., which can "off-tune" TVAs. When TVAs are off-tuned, their effectiveness is sharply reduced. Moreover, the off-tuned TVAs can excessively amplify the vibration levels of the primary structures; therefore, not only rendering the TVA useless but also possibly causing damage to the structures. Off-tuning is one of the major problems of conventional passive TVAs.
This study proposes a novel semiactive TVA, which strives to combine the best features of passive and active TVA systems. The semiactive TVA in this study includes a Magneto-Rheological (MR) damper that is used as a controllable damping element, for providing the real-time adjustability that is needed for improving the TVA performance.
This study is conducted in two phases. The first phase provides a numerical investigation on a two-degree-of-freedom (2-DOF) numerical model in which the primary structure is coupled with a TVA. The numerical investigation considers four semiactive control methods for the MR TVAs, in addition to an equivalent passive TVA. These numerical models are optimally tuned using numerical optimization techniques to compare each TVA system. These tuned systems then serve as the basis for numerical parametric studies for further evaluation of their dynamic performance. The parametric study covers the effects of damping, as well as system parameter variations (off-tuning). The results indicates that semiactive TVAs are more effective in reducing the maximum vibrations of the primary structure and are more robust when subjected to off-tuning. Additionally, the numerical study identifies the "On-off Displacement-Based Groundhook control (on-off DBG)" as the most suitable control method for the semiactive TVA among control methods considered in this study.
For the second phase of this study, an experimental study is performed on a test setup, which represents a 2-DOF structure model coupled with an MR TVA. Using this setup, a series of tests are conducted in the same manner as the numerical study to evaluate the performance of the semiactive TVA. The primary purposes of the experiment are to further evaluate the most promising semiactive control methods and to serve as a "proof-of-concept" of the effectiveness of this MR TVA for floor vibration applications. The results indicate that the semiactive TVA with displacement-based groundhook control outperforms the equivalent passive TVA in reducing the maximum vibrations of the primary structure. This confirms the numerical result that identifies on-off DBG control method as the "best" control method for the MR TVA among four semiactive control schemes considered. The experimental robustness study is also conducted, focusing on the dynamic performance of both the passive and the semiactive TVAs when the mass of the primary system changes (mass off-tuning). The mass of the primary system varied from -23 % to +23 % of its nominal value by adding and removing external masses. The experimental results show that the semiactive TVA is more robust to changes in the primary mass than the passive TVA.
These results justify the benefits of the use of semiactive MR TVAs in structures, such as building floor systems. The off-tuning analysis further suggests that, in practice, semiactive TVAs should be tuned slightly less than their optimum in order to compensate for any added masses to the structure. Additionally, the lessons learned from the experimental study have paved the way for implementing the semiactive MR TVA on a test floor, which is currently in progress under a separate study.Ph. D.
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Allani, Anissa. "Conception et optimisation d'amortisseurs à masse accordée pour les structures du génie civil." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1137/document.
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Le travail de thèse s’appuie sur un recueil exhaustif des travaux effectués dans le domaine du contrôle des vibrations auxquels sont soumis les ouvrages génie civil. Une contribution innovante et originale est apportée et permet de classifier, de généraliser et d’optimiser certains critères dans le but d’assurer une conception optimale de divers dispositifs d’atténuation des vibrations, et ce, selon leur application. L’un des objectifs de la thèse a donc consisté à traiter ces critères de manière originale. Après avoir résolu le problème dit « direct » s’appuyant sur la modélisation des systèmes dotés d’un ou de plusieurs AMAs, nous nous sommes intéressés au problème dit « indirect » en envisageant divers critères d’optimisation. Ainsi, plusieurs critères d’optimisation des paramètres mécaniques de plusieurs AMAs appliqués à un système principal comportant 1 ou plusieurs degrés de liberté peuvent être utilisés. L’excitation du système principal est envisagée de deux manières, soit à sa base (en vue d’une application à la sismique), soit au niveau de la structure (en vue d’une application aux effets du vent).Des simulations numériques sont réalisées dans le but d’étudier la performance de chaque modèle optimisé en se fondant sur des approches fréquentielles et temporelles. La robustesse de chaque critère d’optimisation face aux incertitudes liées au changement des paramètres physiques de la structure principale a été examinée. Nous avons également étudié la sensibilité des critères par rapport aux incertitudes des paramètres optimisés des AMAs. La conception et l’optimisation de p AMAs placés en parallèle pour un système principal à Nddl, a constitué une nouvelle contribution originale dans le cadre de cette thèse. Dans ce contexte, lors d’une sollicitation sismique, nous estimons la contribution de chaque mode dans la structure principale et nous conservons seulement les modes de vibrations qui ont un rapport de masses modales cumulées supérieur à 90%. Le choix du critère d’optimisation s’appuie seulement sur les étages les plus sensibles aux modes conservés et permet ainsi de tenir compte des modes élevés de la structure principale. Dans le but de limiter les dommages subis par les constructions du génie civil lors de sollicitations sismiques, nous cherchons à évaluer l’efficacité des AMAs afin d’atténuer les réponses temporelles sismiques. Ainsi une étude comparative est réalisée en appliquant quatre séismes réels sur les modèles optimisés. Afin d’illustrer les résultats obtenus, des tests de caractérisation d’un AMA utilisant un amortissement par courants de Foucault et un ajustement de la rigidité, ont été menés. Ils ont permis d’obtenir une validation expérimentale du modèle et du critère d’optimisation adoptéThe architectural demand and the desire to reduce costs permit the construction of light structures with innovating shapes. The great flexibility of these structures makes them increasingly sensitive to the external dynamic loads such as traffic, wind and earthquakes. Vibration control techniques allow to construct modern buildings increasingly slender, and, whether they are economic or architecturally audacious. Instead of modifying the geometrical and mechanical characteristics of a structure, vibration control consists in producing reaction forces which are opposed to the negative effects of the external excitations when they appear. This technological advance has the great advantage to not influencing planners and architects’ work and it provides them with additional creative options in both geometrical and mechanical characteristics of buildings. We restrict our focus to passive vibration control. Among available passive vibration absorber systems, Tuned Mass Dampers (TMDs) were selected for their simplicity and reliability. A TMD consists of a mass, a dashpot, and a spring, and is commonly attached to a vibrating primary system to suppress undesirable vibrations. The performance of TMDs is strongly affected by the adjustment of their parameters. The problem is the optimization of the mechanical parameters of TMD and their location in order to attenuate vibrations of the main structure. This thesis is based on understanding the dynamic characteristics of TMD. It aims to make an innovative and original contribution to classify, generalize and optimize some criteria in order to ensure an optimal design of TMDs, depending on their application. Our work consisted to treat these criteria in an original way. After solving the direct problem based on the modelling of systems with one or several TMD, we tackled the indirect problem by considering various optimization criteria. Thus, several optimization criteria of the mechanical parameters of TMDs applied to a main system (single (SDOF) or multiple degrees of freedom (MDOF)) are used. The excitation of the main system can be done in two different ways; either on the base (for seismic application) or on the structure (for wind effects).Numerical simulations based on a time and frequency approach are used to examine the performance of each optimized model. The robustness of each optimization criterion is assessed by taken into account the uncertainties related to the change of the physical parameters of the main structure. Such problems can be discussed by considering sensitivity analysis for criteria under uncertainty of the optimum TMD parameters. A new and original contribution of this thesis is the design and optimization of multiple TMDs in parallel with a MDOF main structure. In this context, during seismic loads, modes in the main structure with relatively high effective masses can be readily excited by base excitation. Afterwards, optimization criterion can be developed based on the most sensitive storeys to vibration modes which are a cumulative modal effective mass fraction exceeding 90%. To protect structures under earthquake loads, we seek to assess the effectiveness of TMDs in mitigating the response of structure under different real earthquakes. A comparative study is then achieved with four real earthquakes applied on systems with TMD optimized parameters. To illustrate the results obtained, characterization tests are conducted on a TMD with damping by eddy currents effect and adjustable stiffness. They allow the validation of the model and optimization criterion adopted
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Liut, Daniel Armando. "Neural-Network and Fuzzy-Logic Learning and Control of Linear and Nonlinear Dynamic Systems." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29163.
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The goal of this thesis is to develop nontraditional strategies to provide motion control for different engineering applications. We focus our attention on three topics: 1) roll reduction of ships in a seaway; 2) response reduction of buildings under seismic excitations; 3) new training strategies and neural-network configurations.
The first topic of this research is based on a multidisciplinary simulation, which includes ship-motion simulation by means of a numerical model called LAMP, the modeling of fins and computation of the hydrodynamic forces produced by them, and a neural-network/fuzzy-logic controller. LAMP is based on a source-panel method to model the flowfield around the ship, whereas the fins are modeled by a general unsteady vortex-lattice method. The ship is considered to be a rigid body and the complete equations of motion are integrated numerically in the time domain. The motion of the ship and the complete flowfield are calculated simultaneously and interactively. The neural-network/fuzzy-logic controller can be progressively trained.
The second topic is the development of a neural-network-based approach for the control of seismic structural response. To this end, a two-dimensional linear model and a hysteretic model of a multistory building are used. To control the response of the structure a tuned mass damper is located on the roof of the building. Such devices provide a good passive reduction. Once the mass damper is properly tuned, active control is added to improve the already efficient passive controller. This is achieved by means of a neural network.
As part of the last topic, two new flexible and expeditious training strategies are developed to train the neural-network and fuzzy-logic controllers for both naval and civil engineering applications. The first strategy is based on a load-matching procedure, which seeks to adjust the controller in order to counteract the loads (forces and moments) which generate the motion that is to be reduced. A second training strategy provides training by means of an adaptive gradient search. This technique provides a wide flexibility in defining the parameters to be optimized. Also a novel neural-network approach called modal neural network is designed as a suitable controller for multiple-input multiple output control systems (MIMO).Ph. D.
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Almeida, Guilherme Mesquita de. "Aplicação de tuned-mass dampers para controle de vibrações em lajes." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-02122016-085411/.
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Esta dissertação propõe uma solução padronizada de aplicação de Tuned-Mass Damper (TMD) para controle de vibrações em lajes baseada na análise das características de carregamentos associados à utilização humana e nas características estruturais mais comuns à engenharia contemporânea. De modo a simplificar sua aplicação técnica, a sintonização é proposta por meio da escolha de componentes pré-determinados para a montagem do TMD e pela distribuição e posicionamento dos mecanismos. A eficácia do sistema é então verificada em um estudo de caso, usando um modelo de elementos finitos de uma laje, antes e depois da aplicação dos mecanismos.This thesis proposes a standardized solution for the application of Tuned-Mass Dampers to the control of floor vibrations based on the characteristics of the acting loads associated to human usage and the characteristics of the most common structures of the contemporary engineering practice. In order to simplify its usage by the technical community, the tuning is proposed through the selection of pre-determined components for the assembly of the TMD and the choice of disposition and spacing of the mechanisms. The system efficacy is then verified in a computational case study, by means of a finite-element model of a floor, before and after the application of the mechanisms.
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Zhou, Shaoyi. "Advances in passive and active damping techniques." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI066.
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Les systèmes mécaniques (e.g. structures flexibles) sont généralement peu amortis, et par conséquent des vibrations de fortes amplitudes peuvent apparaitre. Il apparait nécessaire de développer des stratégies de contrôle vibratoire pour atténuer ces vibrations mécaniques. Cette thèse a pour objectif de développer plusieurs techniques d'amortissement de vibration passives ou actives. La première partie porte sur l'utilisation d'un “inerter” pour améliorer les performances de contrôle vibratoire de deux dispositifs existants, l'amortisseur à masse accordée (TMD) et deux TMDs placés en série (SDTMD). Dans le cas avec un TMD, on considère un système mécanique avec incertitudes ainsi que son optimisation H-infinity (worst-case optimization) en adoptant une approche purement algébrique. Dans le cas de SDTMD, on vise à contrôler la vibration d'un système déterministe. Son optimisation H-infinity s'effectue ici en utilisant une version étendue de la théorie de points fixes (FPT). Dans une seconde partie, on cherche à améliorer les performances de ce type de dispositif en positionnant un élément linéaire de raideur négative entre la base et la masse accordée. Deux cas d'étude sont menés: le TMD seul et celui basé sur l'inerter (IDVA). Les deux dispositifs ont une configuration non-traditionnelle, dont la masse accordée est liée à la base par l'intermédiaire d'un amortisseur visqueux ou un réseau mécanique basé sur l'inerter. La réalisation de ces dispositifs non-traditionnelles avec ou sans raideur négative et leurs shunts piézoélectriques sont étudiés et une analogie électromécanique est établie. Cette analogie permet d'étendre l'applicabilité des amortisseurs mécaniques et de faciliter les réglages. Dans la dernière partie, deux techniques d'amortissement actif et semi-actif sont développées. La première stratégie concerne une loi de contrôle hybride applicable au TMD et à l'IDVA. Le contrôleur proposé est composé d'un seul ou plusieurs compensateurs identiques, qui est caractérisé par un pôle à l'origine et deux zéros coïncidents réels. Les expressions analytiques sont développées dans les deux cas. La seconde technique de contrôle s'appuie sur l'atténuation de vibration par shunt électromagnétique (EMSD), pour laquelle aucun capteur est requis. Une inductance négative (NI) est employée dans les shunts électromagnétiques afin d'améliorer l'amortissement. Trois architectures possibles de NI dans un EMSD sont évaluées à travers le facteur de couplage électromécanique, qui quantifie l'efficacité de conversion énergétique entre les domaines mécanique et électrique. Finalement, six shunts électromagnétiques utilisant des NIs sont optimisés et analysésMechanical systems (e.g. flexible structures) are usually lightly damped so that they vibrate severally in response to dynamic loads. Therefore, vibration control strategies should be adopted in order to reduce the undesired vibration of mechanical systems. The objective of this thesis is to develop multiple vibration control techniques, which are either passive or active. The first part focuses on the application of inerter to enhance the vibration control performance of two existing control devices, the tuned mass damper (TMD) and the series double TMD (SDTMD). The inerter is employed to relate the tuned mass to the ground. In the case of TMD, a mechanical system under stiffness uncertainty is considered and the worst-case H-infinity optimization is addressed by means of an entirely algebraic approach. In the case of SDTMD, the vibration of a deterministic mechanical system is to be controlled and the H-infinity optimal design is carried out via an extended version of fixed points theory (FPT). Instead of using the inerter, the second part consists in improving the control effect by incorporating a linear negative stiffness between the ground and the tuned mass. Two case studies are conducted based on the non-traditional TMD and inerter-based dynamic vibration absorber (IDVA), whose tuned mass is related to the ground by a viscous damper or an inerter-based mechanical network, respectively. Later, the exact electrical realization of non-traditional configurations with or without negative stiffness is proposed, which is based on the piezoelectric transducer enclosed by a particular shunt circuit. This electromechanical analogy enables to extend the applicability of mechanical control devices and to facilitate the precise tuning. In the last part, active and semi-active vibration control techniques are developed. The first strategy consists in enhancing the control capability of passive TMD and IDVA by feeding back the displacement signal of mechanical system to the electromagnetic actuator. The proposed controller can be regarded as one or multiple basic units arranged in series, which is featured by one pole at the origin and two coalesced zeros on the real axis. Distinguished from the previous strategy, the semi-active control technique is based on electromagnetic shunt damping (EMSD), therefore, no additional sensor is required to measure the information of mechanical system. In order to artificially increase the shunt damping performance, the employment of negative inductance (NI) in the shunt circuit is considered. Three possible layouts of NI in the EMSD are assessed in terms of the electromechanical coupling factor, which quantifies the energy conversion efficiency between mechanical and electrical domains. Finally, six types of shunt circuits are optimally tuned according to the FPT and the beneficial effect of NI and the influence of its layout can be underlined
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Lai, Yong-An, and 賴勇安. "Phase Control Tuned Mass Damper." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/k2tccv.
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博士國立臺灣大學
土木工程學研究所
105
Although the energy absorbing ability of the TMD has been discussed by power flow theory, the phase-mechanism of the TMD is not comprehensively discussed. In this study, the phase of the TMD relative to the structure is presented in power flow theory and discussed in detail, and the phase of the TMD relative to the external force is further discussed and described by the power reactance which shows the TMD has the ability to balance the external energy input to the system. Based on the power flow theory, the semi-active phase control tuned mass damper (PC-TMD) is developed and investigated. The phase control algorithm is proposed for the PC-TMD to judge the specific moment to apply friction force by semi-active friction device. By applying the friction force, the PC-TMD mass block moves along the desired trace and back to the 90-degree phase lag to the structure for achieving the maximum power flow. The numerical simulations demonstrate that the PC-TMD outperforms the conventional TMD in structural vibration reduction, especially for mitigating the detuning problem. The simulation results also indicate that the PC-TMD can be utilized for wind loads or base excitation application, and for single-degree-of-freedom (SDOF) structure or multiple-degree-of-freedom (MDOF) structure. In addition, the design parameters of the PC-TMD is the same for both wind loads and base excitation application so that the PC-TMD can be well performed for wind loads and base excitation simultaneously.
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Cheng, Yu-Tien, and 鄭右典. "Control Performance Indicator of Tuned Mass Dampers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/28705448583988187474.
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碩士國立中興大學
土木工程學系所
104
A tuned mass damper (TMD) system consists of an added mass with properly functioning spring and damping elements for providing frequency-dependent damping in a primary structure. After years of analysis and experimental verification, vibration control using tuned mass damper (TMD) for civil structures has been widely accepted and used in high-rise buildings. However, if the TMD frequency is not tuning the natural frequency of the main structure, the control performance will be greatly reduced. In addition, the main structure and the TMD are always constructed together and becoming a highly coupled system. It is hard to identify the dynamic parameters of TMD and the main structure correctly. Therefore, the present study firstly derived the power balance equation between the main structure and the TMD. Then, a TMD control performance indicator was proposed. The performance indicator was verified by numerical simulation and shaking table test. Furthermore, the control performance indicator was extended to be used in multiple tuned mass damper (MTMD) systems. Both theoretical and experimental results show that the proposed TMD/MTMD performance indicator can judge TMD/MTMD’s performance correctly and is benefit to the practical application.
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Su, Yu Hung, and 蘇宇宏. "Floor Vibration Control Using Multiple Tuned Mass Dampers." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/05912340783298004772.
Full textAbstract:
碩士國立中興大學
土木工程學系
92
This paper deals with the analysis of dynamic characteristics of floor structure under different external forces and how to use the control devices such as Multiple Tuned Mass Dampers (MTMD) to reduce the dynamic responses of the floors. In the first part, the vibration control philosophy and optimal design of MTMD are presented and the optimal MTMD parameters will be determined. In the second part, in order to prove the effectiveness of MTMD, and propose a mathematical model of the floors under different external forces to verify the effectiveness of MTMD, and expects the response of the floors to be decreased by the MTMD devices.
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Ou, Nien-Cheng, and 歐念澂. "Real-Time Control Performance Indicators of Tuned Mass Dampers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/60507936214122120292.
Full textAbstract:
碩士國立中興大學
土木工程學系所
105
A tuned mass damper (TMD) system consists of an added mass with properly functioning spring and damping elements for providing frequency-dependent damping in a primary structure. After years of analysis and experimental verification, vibration control using tuned mass damper (TMD) for civil structures has been widely accepted and used in high-rise buildings. However, if the TMD frequency is not tuning the natural frequency of the main structure, the control performance will be greatly reduced. In addition, the main structure and the TMD are always constructed together and becoming a highly coupled system. It is hard to identify the dynamic parameters of TMD and the main structure correctly. Therefore, the present study firstly derived the power balance equation between the main structure and the TMD. Then, an indicator is computed via the phase the response between the TMD and the main structure. And a TMD control performance indicator through moving window was proposed. The real time performance indicators were verified by numerical simulation . Furthermore, the control performance indicators were extended to be used in multiple tuned mass damper (MTMD) systems. Theoretical results show that the proposed TMD/MTMD performance indicators can judge TMD/MTMD’s performance correctly and is benefit to the practical application.
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Huang, Min-Hua, and 黃敏華. "Hibrid Tuned Mass Damper for Vibration Control of Structures." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/73831556853363955306.
Full textAbstract:
碩士國立中興大學
土木工程研究所
82
Previous researches on reduction of structural responses using PTMD (Passive Tuned Mass Damper) did not take the effect of damper strokes into consideration in some cases, strokes of damper might exceed the allowable working space. To overcome this unrealistic situation, a control force can be applied on the device of PTMD to reduce both structural responses and the damper strokes. This research investigates how the structural properties are changed and how much the structural response are reduced when the structures are installed with ATMD (Active Tuned Mass Dampers). The most economical number of sensors and their locations which can reduce structural responses effectively are then suggested based on the analytical result of state feedback theory. The ATMD with state feedback control and an 'appropriate' weighting factors can reduce structural responses and damper strokes than the PTMD. However, if an improper weighting factor is used, the absolute response acceleration of structure will be increasedand the stroke of damper will become larger. hence, the state feedback is not considered to be best way for struct- ural control. As for the direct feedback control, the way to measure the velocity of damper stroke will reduce the stroke of damper significantly and will give a similar analytical to the velocity feedback control produces. Eventually, the direct feedback with measurement of velocity of damper stroke is highly recommended for use in the structural control.
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Chang, Wei-yuan, and 張韋元. "Study of Tuned Mass Damper in Building Structural Control due to Variable Mass." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/61851275431207107195.
Full textAbstract:
碩士中原大學
土木工程研究所
96
Tuned mass damper (TMD) is one of passive controllers. According to previous researches, mass magnitude affects reducing of the building response; however, the most of the mass is fixed. A variable mass method is proposed in this thesis, and the proposed method is demonstrated by high speed pump and the sliding mode control (SMC). In control theory, the proper control rule can not be directly derived from the variable structure control system (VSS) control rule to the ATMD control system since it is canonical control form. The sliding mode control rule is obtained from the transfer matrices, and VSVH pump is applied to be the controller here with the maximum flow rate is 10 . The simulation results show that the tuned mass damper due to variable mass can effectively reduce dynamic response of the buildings under external disturbances. In multiple-degree of freedom system, locating the sensor at the top of the building is effective and that is economical and functional. Additionally, sliding surface coefficients in control rule is changing while mass is decreasing. During control phase, the bigger mass is, the better reducing will be, but interior parameters of buildings will be changed owing to a huge mass. The findings in this thesis can be a reference for a future research.
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穆如蘭. "Study of Active Tuned Mass Damper in Building Structural Control." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/45125999123917650472.
Full textAbstract:
碩士中原大學
土木工程學系
85
The non-canonical control form systen is transformed into the canonical control form system. Then, the results are used to develop the fuzzy sliding mode control(FSMC) in active tuned mass damper (TMP) control system. It is desired that the structure under control can be sustained in safety and stability during external disturbances. The control rule is difficult to derive from the classical control theory for building structural control system using active TMD. Furthermore, the improper control force may cause resonance and failure of the structure. It can''t be derived from the variable structure control system(VSS) theory with single in-put and single out-put system. This thesis takes advantage of tranfer matrices to obtain the sliding mode control rule. It is than combined with the fuzzy theory to develop the FSMC method. It is useful in active TMD control system. Simulation results show that FSMC method is effective for aceive structural control of building systems. Simulation results also show that resonance happens in building structural control system equipped with passive TMD under random force . Moreover, the response is even larger than that without control device. The FSMC method effectively reduces the response of the structural control system under random force as well as wind load. Both the active TMD and the tendon controller are the motion reduction devices in building structures under external forces. It is found that the FSMC method is much better than the state feedback method(SFB) in reducing both the maximum displacement and the maximum control force. Comparing FSMC with VSS, same result can be obtained with FSMC by using smaller controller force. Therefore, FSMC is a more practical method.
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Wu, Hsuan-Yu, and 吳軒宇. "Application of Tuned Mass Damper and Tuned Liquid Column Damper to the Vibrational Control on TAIPEI 101." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/12963891512330801272.
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Hou, Tsung-Chuan, and 侯宗泉. "Instantaneous Phase Detection for Control Performance Verification of Tuned Mass Dampers." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/65601721735468126064.
Full textAbstract:
碩士國立中興大學
土木工程學系所
102
After years of analysis and experimental verification, vibration control using tuned mass damper (TMD) for civil structures has been widely accepted and used in high-rise buildings. However, if the TMD frequency is not tuning the natural frequency of the main structure, the control performance will be greatly reduced. In addition, the main structure and the TMD are always constructed together and becoming a highly coupled system. It is hard to identify the dynamic parameters of TMD and the main structure correctly. Therefore, a simple indicator was developed in this study to judge the control performance of the TMD system. The indicator is computed via the phase the responses between the TMD and the main structure. Firstly, the theoretical derivation illustrates the relationship between the phase and the TMD performance. Then, the proposed phase indicator was verified by numerical simulation. Finally, a main structure controlled by a variable stiffness TMD system was tested via shaking table. The test results indicate the proposed method is effective in judgment of TMD performance.
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Lai, Yong-An, and 賴勇安. "Application of Phase Control for Optimal Design of Tuned Mass Dampers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/90958993035387082224.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
99
The present study aims at developing an optimal design of linear passive tuned mass dampers (PTMD) and proposing the phase control algorithm for semi-active tuned mass dampers (SATMD) and active tuned mass dampers (ATMD). At first, by minimizing the sum of square of structural displacement response, three kinds of optimal design methods are proposed for PTMD - the iteration method, the diagram method and the optimal design formulae. Then, phase control algorithm for SATMD and ATMD is proposed. The principle of phase control algorithm is to keep the TMD response to maintain 90° phase lag to the structure. Finally the PTMD, SATMD and ATMD are, respectively, implemented on the structure of Taipei 101 which is simplified to single degree of freedom and subjected to the design wind forces. The numerical simulation result shows that three kinds of optimal design methods for PTMD may suppress the vibration of structure. Moreover, by the phase control algorithm, SATMD and ATMD not only have better performance than the optimal PTMD, but also improve the robustness. Therefore, even without the optimal design procedure, SATMD and ATMD both are more effective than the optimal PTMD.
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Stewart, Gordon M. "Load Reduction of Floating Wind Turbines using Tuned Mass Dampers." 2012. https://scholarworks.umass.edu/theses/781.
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Offshore wind turbines have the potential to be an important part of the United States' energy production profile in the coming years. In order to accomplish this wind integration, offshore wind turbines need to be made more reliable and cost efficient to be competitive with other sources of energy. To capitalize on high speed and high quality winds over deep water, floating platforms for offshore wind turbines have been developed, but they suffer from greatly increased loading. One method to reduce loads in offshore wind turbines is the application of structural control techniques usually used in skyscrapers and bridges. Tuned mass dampers are one structural control system that have been used to reduce loads in simulations of offshore wind turbines. This thesis adds to the state of the art of offshore wind energy by developing a set of optimum passive tuned mass dampers for four offshore wind turbine platforms and by quantifying the effects of actuator dynamics on an active tuned mass damper design.
The set of optimum tuned mass dampers are developed by creating a limited degree-of-freedom model for each of the four offshore wind platforms. These models are then integrated into an optimization function utilizing a genetic algorithm to find a globally optimum design for the tuned mass damper. The tuned mass damper parameters determined by the optimization are integrated into a series of wind turbine design code simulations using FAST. From these simulations, tower fatigue damage reductions of between 5 and 20% are achieved for the various TMD configurations.
A previous study developed a set of active tuned mass damper controllers for an offshore wind turbine mounted on a barge. The design of the controller used an ideal actuator in which the commanded force equaled the applied force with no time lag. This thesis develops an actuator model and conducts a frequency analysis on a limited degree-of-freedom model of the barge including this actuator model. Simulations of the barge with the active controller and the actuator model are conducted with FAST, and the results are compared with the ideal actuator case. The realistic actuator model causes the active mass damper power requirements to increase drastically, by as much as 1000%, which confirms the importance of considering an actuator model in controller design.
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Lien, Chien-Hsun, and 練健勳. "Parametric Design and Vibration Control of Multiple Tuned Mass Damperwith Confined Stroke." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/19848826798088951317.
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Liu, Su-Yu, and 劉素妤. "Vibration Control of Torsionally-Coupled Base-Isolated Structures Using Tuned Mass Dampers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/22696395475374710449.
Full textAbstract:
碩士國立中興大學
土木工程學系所
100
This study deals with the practical design consideration and vibration control effectives of tuned mass damper (TMD) for torsionally-coupled base isolated structures under ground motions. The optimal parameters of TMD are determined by minimizing mean-square displacement response ratio contributed by the first three modes of controlled degree-of-freedom between the structures with and without TMD. A planar base-isolated structure under four selected ground motions is firstly simulated. The effectiveness of the TMD under different eccentricities of the primary structure is then discussed. A reduction of approximate 30% in base displacement and structure absolute acceleration of root mean square (RMS) under soft soil ground motion record. However, a reduction of approximate 15% in base displacement and structure absolute acceleration of root mean square (RMS) under firm soil ground motion records. The TMD is effective when the base isolated structure and the soft soil ground motion. However, the effectiveness is not obvious under firm soil ground motion, because of the well performance of the base isolation system.
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Lourenco, Richard. "Design, Construction and Testing of an Adaptive Pendulum Tuned Mass Damper." Thesis, 2011. http://hdl.handle.net/10012/5776.
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The objective of this thesis is to describe the design, construction, implementation and performance of a prototype adaptive pendulum tuned mass damper (APTMD). Furthermore the thesis aims at demonstrating the performance improvements obtained when the tuned mass damper (TMD) parameters are optimized. The study considers the effect of adjusting the APTMD tuned frequency and damping ratio on a two storey test structure subjected to broadband and narrowband excitation.
An analytical model of the APTMD for a single-degree-of-freedom (SDOF) structure is used to demonstrate the performance improvements when the APTMD parameters are optimized. The optimized model considers the effects of adjusting the frequency ratio, damping ratio, and mass ratio of the combined system to reduce the maximum deflection when the structure is subjected to a harmonic excitation force. The analytical model is used to simulate the optimal performance of the APTMD system.
The experimental APTMD is capable of identifying the structural vibration modes in real time and tuning to the desired mode. The structural vibration modes are identified by calculating the windowed power spectral density of the structure’s acceleration, followed by peak-picking algorithm to identify the modal frequencies. Tuning is performed by moving the pivot location of the pendulum arm via a tuning frame along a set of rails. The design also allows for changes in the external dampening force. An adjustable damper is attached to the pendulum mass to allow for control of the APTMD damping ratio.
A prototype of the APTMD is built and tested in a modal testing setup. The test structure is a two-storey model of a building structure. The structure is excited using a shaker fixed to the lower storey of the structure. The performance of the APTMD under broadband and narrowband excitation is examined for various tuning and damping parameters. The performance of the APTMD system under optimally tuned and detuned conditions is investigated.
The results of the experimental studies demonstrate the importance of optimizing the TMD tuned frequency and damping ratio to reduce structural vibrations. Since the APTMD is designed to autonomously update both parameters, it is an effective tool in mitigating structural vibrations where user interaction is either difficult or expensive. Further study on the performance of a prototype APTMD applied to a large scale structure is required before implementation on full-scale structures.
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Hung, Ta-Chih, and 洪大智. "Vibration Control of Structures Using Electromagnetic Multiple Tuned Mass Dampers with Rotary Transducers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/01051885222650110168.
Full textAbstract:
碩士國立中興大學
土木工程學系所
105
In the 21st century, the once-considered tallest building in the world is constantly challenged by taller skyscrapers every year. However, as the building rises higher, the vibration problem emerges as well. This becomes a stumbling block to engineers who aim for both safety and comfort of residents in this competition. Different approaches have been proposed in order to alleviate the excessive vibration. Among those, multifunctional control devices raise great interests. Devices that mitigate vibration and harvest vibrational energy simultaneously are especially promising due to the craving for more sustainable building technologies. Multiple tuned mass dampers (MTMD) are preferable vibration control devices in the field of passive structural control. Compared with conventional single TMD that suffers from frequency detuning effect, the proposed MTMD, TMD units arranged in parallel, suppresses broader bandwidth and thus provides a more robust control. In this study, a new type of MTMD, called electromagnetic MTMD (EM-MTMD) is developed to refine the existing viscous dampers in the MTMD systems. By replacing the dampers with electromagnetic rotary transducers, a more flexible viscous damping can be achieved and the energy originally dissipated by the dampers could potentially be harvested. Moreover, unlike the viscous damper whose stoke is limited by the manufacturing technology, the stoke of EM-MTMD can be expanded by simply adding more gear racks. Optimal control theory considering the inerter of rotary transducers was studied and illustrated by numerical simulations. The results show that EM-MTMD not only reduces the vibration effectively but also generates considerable amount of energy under seismic excitations.
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Beygi, Heydar. "Vibration Control of a High-Speed Railway Bridge Using Multiple Tuned Mass Dampers." Thesis, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-178055.
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In the current thesis, the Banafjäl Bridge located on the Bothnia line (Botniabanan) in northern Sweden was studied. The bridge is a 40m long composite ballasted high-speed railway bridge. A 3D FE model of the bridge was developed using a commercial FE software, Abaqus. The FE model was calibrated against the measured data of the bridge. The dynamic response of the bridge's FE model was investigated under the dynamic load of the passing HSLM-A train using modal dynamic analysis. The vertical acceleration induced by excitation of the passing train exceeded the permissible limit of 3.5 m/s2 for the speed range of 220-240 km/h. Thus, damping solutions using multiple tuned mass dampers (MTMDs) were investigated. According to the results of this study, a 4 tonnes MTMD system consist of 5 parallel TMDs attached to the mid-span of the bridge could effectively control the undesired vibration of the bridge. The suggested solution could account for the changes in the stiffness of the bridge caused by freezing and ice forming in the ballast.
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Sun, David, and 孫大衛. "Wind-Induced Vibration Control of Long-Span bridges By Multiple Tuned Mass Dampers." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/78267143490976479541.
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碩士淡江大學
土木工程學系
85
Developments of construction methods and improvements of materials have led to the use of longer spans and more slender sections in modern bridge design. Therefore, the susceptibility of this type of bridges to wind excitation becomes more significant. The most prominent aerodynamics on bridges are known as flutter and buffeting. When buffeting response is larger than the tolerable value at the design wind speed, the response should be controlled by some devices. Among the vibration control devices, MTMDs are recently proposed and proven to be effective against harmonic loads. Because wind loads are not harmonic, the effectiveness of MTMD used in long-span bridges subjected to wind excitation should be studied further.In general, the vertical or torsional motion of long-span bridge is dominated by the structure''s first mode in that direction. Hence, it is possible to model the bridge as a SDOF system and each TMD of the MTMDs also as a SDOF system. Then, the equations of motion can be formulated based on the N+1 DOF system. And the dynamic response of the bridge and TMDs are easily obtained by using of the transfer functions. The dynamic response reductions and the increase of the flutter velocity due to the addition of the MTMDs on the bridge are discussed. Through a parametric analysis, the design properties of the MTMDs are studied and the design procedures are proposed. The comparison of effectiveness between a single TMD and the MTMD is also provided in this paper. Also, the increase of the flutter velocity of the flexible bridge due to the addition of MTMDs is discussed. The results show that the MTMDs are more effective and more robust than a single TMD against the vibration induced by buffeting. The performance in torsional direction is extremely well as the wind velocity approaches to the flutter velocity.
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Wang, Jer-Fu, and 王哲夫. "Vibration Control of Structures with Multiple Tuned Mass Dampers Considering System Interaction Effects." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/24829299085068070857.
Full textAbstract:
博士國立中興大學
土木工程學系
89
In recent years, the use of active and passive control devices such as Passive Tuned Mass Damper (PTMD) to reduce the dynamic responses of structures under strong environmental loadings has become an area of considerable research interest. Due to recent intensive analytical and experimental studies, vibration control of structures using PTMDs is gaining more acceptance not only in the design of new structures and components but also in the retrofit of existing structures to enhance their reliability against winds, earthquakes and human activities. Basically, a PTMD is a device consisting of a mass connected to structures using a spring and a viscous damper. The PTMD has the control effectiveness by tuning its frequency to the primary structural frequency. Therefore, it is generally recognized that the design of an optimal PTMD requires a prior knowledge of the modal parameters of the controlled structure to achieve the desired vibration control effectiveness. In practical applications, the PTMD probably does not tune to the right frequency, so that the detuning effect deteriorating the PTMD control effectiveness will occur. In the first part of this thesis, the vibration control philosophy and optimal design of passive tuned mass dampers (PTMDs) for a multi-degree-of-freedom (MDOF) structure are presented. In order to accurately evaluate the structural parameters and prove the effectiveness of PTMD, an modal parameters identification technique is intruduced to calculate the modal frequencies, damping ratios, and mode shapes based on only a few floor response measurements. Numerical results throughout a five-story building under ambient random excitations demonstrated that the proposed system identification techniques are able to identify the dominant modal parameters of the system accurately, even with high closed-space frequencies and noise contamination. To assess structural dynamic responses more accurately, many exact mathematical models were proposed and the error of conventional structural models was estimated carefully. It is found that the system interaction effect, such as vehicle-bridge interaction and soil-structure interaction, will modify the original properties of structures even if the structural materials are maintained within the linear range. In the second of this thesis, these interaction effects are further investigated to avoid overestimation of PTMD control performance. With the understanding of system interaction effect, this study pays much effect on the determination of the optimal MTMD system parameters. The MTMDs are then applied to reduce vibration of train-bridge interaction system and soil-structure interaction system. From the numerical investigations about the Taiwan High Speed Railway bridge and irregular buildings on soils, it is proved that the MTMD is more effective than single PTMD.
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Chen, Chi-Lun, and 陳啟倫. "Vibration Control of Structures Using Multiple Tuned Mass Dampers under Near-Fault Earthquakes." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/48107385876891154983.
Full textAbstract:
碩士國立中興大學
土木工程學系
92
This paper deals with the passive Multiple Tuned Mass Damper (MTMD) for reducing the dynamic response of structure under Near-Fault earthquake excitations. Three velocity pulse-likes developed by Nicos Makris are employed to simulate Near-Fault earthquake. The vibration control effectiveness are extensively investigated through the comparison of response spectrum, response time history, and the energy dissipation time history of the structure with and without MTMDs. Numerical studies show that although the passive MTMD could not reduce the maximum response in the pulse duration significantly, but the structural response decay quickly after impulse. According to various types of impulses, it can be observed that the more cycles of pulse, the more useful for MTMDs to reduce the peak structural response. From the viewpoint of energy dissipation, it is also found that structural damage can significantly eliminated because most earthquake energy is dissipated by MTMDs and the rate of energy dissipation is much faster than those of structures without MTMDs.
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Chen, Jia-Xian, and 陳家賢. "Optimal and Fuzzy Vibration Control of Bridge TowerUsing Active and Passive Tuned Mass Dampers." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/77902646983322314709.
Full textAbstract:
碩士國立高雄應用科技大學
土木工程與防災科技研究所
94
Large span bridges supported by cables such as suspension bridges and cable-stayed bridges are widely used recently. However, the structure of bridge towers is often characterized by light mass, high strength but low stiffness and thus subjected to larger deflection than the bridge pier. Vibration of bridge towers often causes vibration of cable ropes and vice versa. Violent vibration of cable ropes has great influence on bridges and vehicles, it is very important to reduce vibration of bridge towers under various dynamic loadings. The research is aimed at the optimal and fuzzy vibration control of bridge towers using passive and active tuned mass dampers (TMDs). The bridge tower is considered to be an elastic cantilever beam, which is fixed at one end and elastically supported at the other end. Method of assumed modes is employed to transform the elastic tower into generalized coordinates with finite degrees of freedom. Equations of motion of multi-degrees-of-freedom discrete dynamic system of bridge tower and TMD are then expressed in state space description. Runge-Kutta scheme is employed for the calculation of the dynamic responses of uncontrolled and controlled systems under free vibration, unit step excitation, harmonic excitation and El Centro ground motions. In the passive control study the parameters of the TMDs are adjusted to achieve the best values. In the active control synthesis, proportional gains, pole-assignment method, optimal control based on steady state linear quadratic regulator theory (SSLQR) and fuzzy control logics are employed to design the state feedback control laws. The numerical results show that dynamic responses of bridge towers can be reduced by the use of TMDs with adequate choice of proportional gains, poles of systems, weighted matrices and fuzzy rule bank and membership functions. It is also found that active control strategies are better than the passive ones.
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Jhang, Hong-shin, and 張弘欣. "Robust Vibration Control of a Building Structure with Tuned Mass Damper Subject to Earthquake." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58481678667376501576.
Full textAbstract:
碩士國立高雄應用科技大學
機械與精密工程研究所
96
This thesis presents a robust vibration control approach for a building structure with Tuned Mass Damper (TMD) subject to time-varying parameter perturbations and earthquake. The building structure with a TMD is first mathematically modeled[1], in which the TMD parameters are chosen based on [13,14,16~19]. For the vibration control, the state feedback gain matrix and observer gain matrix are designed by using Hybrid Taguchi-Genetic Algorithm (HTGA). Then, a sufficient condition in terms of linear matrix inequalities (LMIs)[5,6] is employed to guarantee that the resulting control system in the presence of time-varying parameter perturbations and earthquake is asymptotically stable. Finally, simulation example is given to demonstrate the use of the design approach. The results show that the designed controller can reduce vibration behavior and keep the building structure with TMD from the possibility of instability caused by time-varying parameter perturbations and earthquake.
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Lin, Fu-Xiang, and 林富祥. "Vibration Control of Seismic Structures Using Multi-Functional Electromagnetic Semi-active Tuned Mass Dampers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/31957226768574619828.
Full textAbstract:
碩士國立中興大學
土木工程學系所
103
Conventional tuned mass damper (TMD) is a popular and generally accepted vibration control device in the field of passive structural control. A TMD system consists of an added mass with properly functioning spring and damping elements that provide additional damping in a primary structure. By attaching a TMD to a structure, vibration energy of the structure can be transferred into the TMD and dissipated via the damping mechanism. The application of tuned mass dampers (TMD) for vibration control of civil engineering structures has been widely accepted after numerous analytical studies, experimental, and field verifications. A large number of TMDs have been implemented in real structures against natural and man-made excitations since early 1970. However, when vibration energy of the structure transferred into the TMD, energy dissipated by a damper becomes a waste from the energy point of view. This project aims to develop a multi-functional electromagnetic semi-active TMD, (called MFE-SATMD), which consists of a mass block, springs, RLC circuit, and motors. The MFE-SATMD can generate electricity by the power generator and also provide control force by a control motor. A general semi-active control algorithm will be developed for the MFE-SATMD. The control algorithm has two functions: energy harvesting and vibration control. The detuning effect can also be mitigated by changing the parameters of the circuit appropriately.
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Yang, Ting-Wei, and 楊庭維. "Vibration Control of Seismic Structures Using Semi-active Friction Typed Multiple Tuned Mass Dampers." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/64028821788277972506.
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碩士國立中興大學
土木工程學系所
97
The design and application of linear typed tuned mass damper(TMD) systems are well developed, nonlinear TMD systems are still developing.In this paper, statement about friction typed TMD system, which is one kinds of nonlinear TMD. Friction typed TMD energy dissipating by friction mechanism, there is no need for the installation of extra damping device. But passive friction multiple TMD(PF-MTMD) slip load is fixed and pre-determined value. The PF-MTMD may lose its tuning and energy dissipating ability when the PF-MTMD is in its stick state. In order to overcome this problem, a semi-active friction multiple TMD(SAF-MTMD) in this paper. SAF-MTMD is composed of a mass and a semi-active friction device (SAFD). The friction forces of the SAFD is controllable. A non-sticking friction (NSF) control law, which is able to keep SAF-MTMD activated throughout an earthquake with arbitrary intensity, was conducted. The performance of PF-MTMD and SAF-MTMD for protection of seismic structures was investigated numerically.
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Tsai, Yu-Jen, and 蔡友仁. "Parametric Design and Vibration Control of Multiple Tuned Mass Damper with Considering Detuned effect." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/63672266039672132415.
Full textAbstract:
碩士國立中興大學
土木工程學系所
96
The primarily research of this article is the optimum parametric design of Multiple Tuned Mass Damper (MTMD) with considering detuned effect. We attempt to design one set of MTMD parameters by using a new vibrated reduced index. And this MTMD set is going to show the better behavior in vibrated response reduction than the MTMD set designed by traditional method as the targeted structure is detuned. We’ll prove the possibility of the method by comparing with other three traditional design method in numerical approximate and dynamic analysis that use the real earthquake time history record as input applied force. To continue, we focus on the new designed MTMD, discussing the variation of the reduction effect by changing numbers of MTMD. And in the end, we make a conclusion to this research.
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Su, Kuan-Chung, and 蘇冠中. "Parametric Design and Vibration Control of Multiple Tuned Mass Damper with Considering Design Spectrum." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/76937095022919674144.
Full textAbstract:
碩士國立中興大學
土木工程學系所
96
This article mainly introduces a new MTMD parameter design method:parametric design of Multiple Tuned Mass Damper with considering design spectrum. Will compare inputs the external force consideration to the tradition for the white noise MTMD parameter design method, considered the design spectrum, expected will be able to reflect the different local characteristic to the structure influence by the design spectrum. In the article will aim at two kind of structures with different period, short period and long period, compared with in the traditional design method and considering design spectrum method, the input external force for the white noise will reduce effect to compare; And compare two designs methods with reduces effect and detund effect in three real earthquakes inputs. The result showed that, in the structure for long period situation, considering design spectrum method compares to the traditional MTMD parameter design method, no matter in reduces effect to the detund effect , all has a more outstanding performance, has a more outstanding performance.
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Lin, Yu-Hsin, and 林育信. "Vibration Control Effectiveness of Soil-Irregular Building Systems equipped with Multiple Tuned Mass Dampers." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/71389614992962915267.
Full textAbstract:
碩士國立中興大學
土木工程學系
90
This thesis deals with the analysis of dynamic characteristics of soil-irregular building interactive system, the MTMD parameter design considering the soil-structure interaction (SSI) effect, and the investigations of MTMD control effectiveness under bi-directional earthquake excitations. The optimal MTMD parameters are determined by minimizing the mean-square displacement response ratio contributed by the first three modes of controlled degree-of-freedom between the building with and without MTMD. According to this research, it is shown that the existence of SSI effect will reduce the modal frequencies of the combined building-soil system. Without considering the SSI effect, the MTMD probably does not tune to the right frequency, so that the detuning effect deteriorating the MTMD control effectiveness will occur. In this study, the MTMDs with the consideration of the SSI effect are useful as the buildings are built on hard soils. On the soft soil, the MTMDs become less effective in most situations because of the increase of system damping. Only for the slender building with significant foundation rocking, the MTMD control effectiveness is more obvious.
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Liu, Chieng-Ming, and 劉建泯. "Optimal and Fuzzy Vibration Control of Bridges Using Active and Passive Tuned Mass Dampers." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/96912065401465028615.
Full textAbstract:
碩士國立高雄應用科技大學
土木工程與防災科技研究所
93
The aseismic capacity of civil engineering structures is of the most importance in Taiwan due to its location near the common boundaries of Euro-Asian Plate and Pacific Plate. Bridges are the key communication channels for people in daily use and disaster rescue. The research is aimed at the optimal and fuzzy vibration control of bridges using passive and active tuned mass dampers (TMDs). Mathematical modeling of uncontrolled and controlled bridge structures are first built as single- and multi- degrees-of freedom dynamic systems, and then Runge-Kutta scheme is employed for the calculation of the dynamic responses. In the passive control study the parameters of the TMDs are adjusted to achieve the best values. In the active control synthesis, proportional gains, pole-assignment method and optimal control based on steady state linear quadratic regulator theory (SSLQR) are employed to design the state feedback control laws. Finally, fuzzy control logics along with well designed membership functions and fuzzy inference rule bank are also adopted to design an alternate control loop to test the validity of applying TMD to bridge vibration suppression. The numerical results show that active control strategies are better than the passive ones.
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Liu, Kun-Chung, and 劉坤彊. "Application of Tuned Mass Damper to the Floor Vibration Control of High-Tech Factory." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/27765108883912004162.
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Shia, Syuan, and 夏瑄. "Seismic Design of Passive Tuned Mass Damper and Base Isolation Using Active Control Algorithms." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/vk9nw5.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
105
Seismic isolation and tuned mass damper (TMD) have been widely accepted as a passive control strategy for protection of structures. A base-isolated building employs a flexible element underneath the structure that shifts the fundamental frequency of the building away from the dominant frequencies of earthquakes. Due to the fact that the flexible element can introduce excessive displacements at base during severe earthquakes, additional viscous damping devices are recommended to be installed along with the isolation layer in most seismic design codes. On the other hand, a TMD system consists of a mass, spring, and damping device with a tuned frequency, thus the response of the structure can be regulated by the effect of resonance. In tall buildings, TMD is usually employed to reduce structural responses against strong winds and earthquakes. Therefore, the objective of this study is to develop new design procedures for base-isolated buildings and buildings with a tuned mass damper. In these design procedures, both stiffness and damping are concurrently determined using the feedback control algorithm, e.g., the linear quadratic regulator (LQR) control algorithm or linear quadratic Gaussian control algorithm. In the seismic isolation design procedure, the mass, damping, and stiffness of a superstructure is assumed to be known, and a mass ratio between the superstructure and isolation layer is predetermined. The stiffness and damping coefficient of the base isolation can be obtained by the LQR control algorithm, while these two terms vary with the weighting selected in LQR. To determine the most appropriate stiffness and damping, a performance curve is generated in terms of maximum time- or frequency-domain responses. Note that the time-domain responses are obtained when the isolated building is subjected to spectrum-compatible ground motions. Subsequently, the stiffness and partial damping coefficient are achieved by lead-rubber bearings, while the remaining damping coefficient is realized by additional viscous dampers. Moreover, the detailed design of lead-rubber bearings is parameterized by a bi-linear model, consisting of the designed stiffness, damping coefficient, pre-to-post yielding stiffness ratio, and a target displacement. In the TMD design procedure, the mass, damping, and stiffness of a primary structure is assumed to be known, and a mass ratio between the primary structure and TMD is predetermined. The stiffness and damping coefficient of the TMD can be obtained by the feedback control algorithm in accordance with different control objectives, and these two terms can be realized by varying the weightings selected in the control algorithm. Then, the maximum poles in transfer functions are employed to determine the most appropriate parameters, which result in the minimum poles among a number of transfer functions. Consequently, the optimal natural frequency and damping ratio of TMD system are achieved. In this study, several numerical examples are carried out to demonstrate the proposed design procedures. Moreover, the numerical study also examines various sets of optimum parameters in different scenarios. As shown in the simulation results, the seismic isolation and TMD design procedures are quite effective for buildings against earthquakes.
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Kheirkhah, Sina. "Vortex-induced vibrations of a pivoted circular cylinder and their control using a tuned-mass damper." Thesis, 2011. http://hdl.handle.net/10012/5937.
Full textAbstract:
Vortex-induced vibrations of a pivoted circular cylinder and control of these vibrations were investigated experimentally. A novel experimental setup was employed to reproduce orbiting response observed in some engineering applications. An adaptive pendulum tuned-mass damper (TMD) was integrated with the cylindrical structure in order to control the vortex-induced vibrations. All experiments were performed at a constant Reynolds number of 2100 for a range of reduced velocities from 3.4 to 11.3
and damping ratios from 0.004 to 0.018. For the experiments involving TMD, the TMD mass ratio was 0.087 and the TMD damping ratios investigated were 0 and 0.24. The results of the experiments performed without the TMD show that, in the synchronization region, the frequencies of transverse and streamwise vibrations lock onto the natural frequency of the structure. The cylinder is observed to trace elliptic trajectories. A mathematical model is introduced to investigate the mechanism responsible for the occurrence of the observed elliptic trajectories and figure-8 type trajectories reported in previous laboratory investigations. The results show that the occurrence of
either elliptic trajectories or figure-8 type trajectories is governed primarily by structural coupling between vibrations in streamwise and transverse directions. Four types of elliptic trajectories were identified. The results show that the occurrence of the different types of elliptic trajectories is linked to phase angle between the streamwise and transverse vibrations of the structure, which depends on structural coupling.
The results of the experiments performed to investigate effectiveness of the TMD in controlling vortex-induced vibrations show that tuning the TMD natural frequency to the natural frequency of the structure decreases significantly the amplitudes of transverse and streamwise vibrations of the structure. Specifically, the transverse amplitudes of vibrations are decreased by a factor of ten and streamwise amplitudes of vibrations are decreased by a factor of three. The results show that, depending on the value of the TMD damping ratio, the frequency of transverse vibrations is either characterized by the natural frequency or by two frequencies: one higher and the other lower than the natural frequency of the structure, referred to as fundamental frequencies. Independent of TMD damping and tuning frequency ratios, the frequency of streamwise vibrations matches that of the transverse vibrations in the synchronization region, and the cylinder traces elliptic trajectories. The phase angle between the streamwise and transverse vibrations is nearly constant when the pendulum is restrained. However, with the TMD engaged and tuned to the natural frequency, the phase angle fluctuates significantly with time. A mathematical model was utilized to gain insight into the frequency response of the structure. The results of the modeling show that the frequency of transverse vibrations is characterized by the fundamental frequency or frequencies of the structure and the frequency of streamwise vibrations is characterized by
the fundamental frequency or frequencies as well as the first harmonic of the fundamental frequency or frequencies of the structure.
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Su, Hui-Wen, and 蘇慧紋. "Structural Control of Tuned Mass Dampers with Resettable and Variable Stiffness Considering Time Delay Effect." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/5wsmrx.
Full textAbstract:
碩士國立中興大學
土木工程學系所
101
A resettable variable stiffness tuned mass dampers (RVS-TMD) is a nonlinear typed TMD. The RVS-TMD consists of a TMD and a resettable variable stiffness device (RVSD). The RVSD composed of a resettable element and a controllable stiffness element. By varying the stiffness element of the RVSD, the force produced by the RVSD can be controlled smoothly through a semi-active control law. By resetting the resettable element, the hysteresis loop of the RVSD can cover all four quadrants in the force-deformation diagram and thus results in more energy dissipation. In this study, time-delay effect of the RVS-TMD is investigated. The RVSD control force is determined by the active control law. When applying the RVSD force, the problem of time-delay is inevitable. To improve the control performance, the control gain with consideration of time-delay is applied to the RVS-TMD system. The numerical results show that with the increasing of delay time, the improvement of the control performance becomes obvious. The control performance of RVS-TMD system can be very close to those of active TMD (ATMD), and is able to reduce the structural response and control force. When the frequency of the primary is changed, by introducing a new designed control gain, the detuning effect is able to be alleviated.
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He, Yu-Bo, and 何玉泊. "Shaking table test and vibration control analysis of semi-actively friction-typed tuned mass dampers." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/85181474766679202330.
Full textAbstract:
碩士國立中興大學
土木工程學系所
98
A TMD system consists of an added mass with properly functioning spring and damping elements that provide frequency-dependent damping in a primary structure. The design and application of linear typed tuned mass damper systems are well developed, nonlinear TMD systems are still developing. A friction-type TMD, i.e. a nonlinear TMD, has the advantages of energy dissipation via a friction mechanism. However, a passive-friction TMD (PF-TMD) has such disadvantages as a fixed and pre-determined slip load and the PF-TMD may lose its tuning and energy dissipation abilities when the PF-TMD is in its stick state. A semi-active-friction TMD (SAF-TMD) is used to overcome these disadvantages. The SAF-TMD is composed of a mass and a semi-active friction device. The friction force of the semi-active friction device is controllable. A non-sticking friction (NSF) control law, which is able to keep SAF-TMD activated throughout an earthquake with arbitrary intensity, was conducted. In this thesis, both theoretical and experimental investigations were conduced for the SAF-TMD system. The test results also demonstrate that the dynamic responses are very consistent with the theoretical ones obtained from numerical simulation. This verifies the feasibility and efficiency of the SAF-TMD system.
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Chiang, Hung-Wei, and 江宏偉. "Shake Table Test of Control Effectiveness of Multiple Tuned Mass Dampers with Constraint of Stroke." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/60628612232865136205.
Full textAbstract:
碩士國立中興大學
土木工程學系所
96
This thesis primarily deals with the stroke issue of Multiple Tuned Mass Damper (MTMD) which might meet constraint in practice for the vibration control of building. A stroke weighting factor is introduced in the parameter design stage to consider the importance of MTMD stroke. The idea is to obtain an MTMD parameter set that induces acceptable structural control effectiveness but large MTMD stroke reduction. Besides analytical study, this idea was also conducted experimentally by shaking table tests of a full-scale three story building with an actual MTMD prototype. The moving mass of the MTMD prototype is 360 kilograms (2% of total mass of test building) which consists of 5 units of TMDs. Each TMD has the identical damper and spring configurations for economical reason. The mass and the damper coefficient of TMD are adjustable. The shaking table tests were conducted at National Center on Research of Earthquake Engineering (NCREE). Various earthquake inputs were used to verify the structural control efficiency and MTMD stroke reduction. Experimental results demonstrate that reduction in MTMD’s stroke is observed with little sacrifice in roof acceleration control. The test results also show that building responses could be dominated by the higher modes because of low damping ratios. To solve this problem, the smallest unit of TMD is designed to tune the higher mode. Numerical simulation results show the newly designed MTMD is capable of controlling the multiple modal responses of the building. Shaking table tests for the newly designed MTMD is scheduled.
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Yang, Tsung-Han, and 楊宗翰. "Shaking Table Test of Multiple Tuned Mass Dampers for Vibration Control of Long Period Structures." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/31314776180183581132.
Full textAbstract:
碩士國立中興大學
土木工程學系所
102
A multiple TMD (MTMD) consists of multiple units of tuned mass dampers (TMDs) arranged in parallel to deal with one single structural mode. By attaching MTMD to a structure, vibration energy of the structure can be transferred to the MTMD and dissipated via the damping mechanism. Compared with the single TMD, the MTMD performs better and is able to avoid detuning effect. However, it is generally understood that the existing TMDs in the high-rise buildings in Taiwan, their design and manufacture all relied on foreign consultants and techniques. Hence, there is cooperation between China Steel Structure Co., Ltd and this research from 2012. We develop MTMD system that has the characteristic of long period and stroke to supply more demands of vibration damping of high building. We used the formula of curved surface first in this research to design and produce a long period main structure system. Then we proceed with the MTMD design of optimization by parameter identified the movement of main structure and we adjust the frequency on site. At last, we install the MTMD system on main structure to proceed with the experiment. The result of experiment shows that the design of MTMD system in this research could efficiently reduce the vibration of long-period structure. The result of experiment and the theory perfectly match and prove the accuracy of the way we analyze in this article.
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Liao, Wei-Ru, and 廖偉汝. "The Vibration Serviceability of Footbridge and Tuned Mass Dampers for Vibration Control of Experiment Validation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/61561201412628534199.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
104
With the development of materials and architectural aesthetics, more and more lightweight and long span bridges began to emerge. These footbridges have low frequency and low-damping characteristics. These may susceptible for human-induced vibrations and the pedestrian may feel uncomfortable to cross. Therefore, the footbridge designer need to recognize the issues of vibration comfort. The main objective of this thesis is assessment of vibration comfort of footbridges under pedestrian loading and analyze the reduction vibrations of the footbridge with TMD. There are summed up the evaluation process based on the foreign related research and analyze a case of domestic footbridge. Assessing whether or not the vibration comfort acceptable through compared the difference with measurement and simulation. After preliminary assessment of comfort, the vibration problem exist in this case can be found. This footbridge case adopted TMD to reduce vertical vibration. In this paper, there are analysis of effect of vibration reduction of SDOF system installed passive TMD and compared the measurement. The results show that the footbridge with TMD meets the requirements of comfort.