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Dissertations / Theses on the topic 'Multiple tuned mass dampers'

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Published: 3 June 2025

Last updated: 19 July 2025

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Chinien, Lomadeven Viken. "Design of multiple tuned mass dampers for mitigation of wind induced vibrations." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/11536.

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Rossato, Luciara Vellar. "Otimização de amortecedores de massa sintonizados em estruturas submetidas a um processo estacionário." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/163246.

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Atualmente as estruturas estão sendo avaliadas para um maior número de ações em relação há algumas décadas. Esta melhoria ao longo da fase de concepção é dada devido ao fato de que está se tornando mais competitivo o fornecimento de estruturas leves e esbeltas, sendo solicitados, cada vez mais, projetos com menor custo de implantação. Devido a isto, é necessário avaliar as estruturas não apenas sujeitas a cargas estáticas, mas também a carregamentos dinâmicos. As ações dinâmicas que atuam sobre uma estrutura podem ser muito mais prejudiciais do que as estáticas quando não são bem consideradas e dimensionadas. Ações dinâmicas podem ser provenientes de tremores de terra, vento, equipamentos em funcionamento, deslocamento de pessoas, veículos em movimento, motores desbalanceados, entre outras fontes, o que pode causar vibrações na estrutura, podendo levar a mesma ao colapso. A fim de controlar e reduzir as amplitudes de vibração, entre outras alternativas é possível a instalação de amortecedores de massa sintonizado (AMS), que é um dispositivo de controle passivo. O AMS tem várias vantagens, tais como a grande capacidade de reduzir a amplitude de vibração, fácil instalação, baixa manutenção, baixo custo, entre outras. Para se obter a melhor relação custo-benefício, ou seja, a maior redução de amplitude aliada a um menor número de amortecedores ou a uma menor massa, a otimização dos parâmetros do AMS tornase fundamental. Neste contexto, este trabalho visa, através de simulação numérica, propor um método para otimizar parâmetros de AMSs quando estes devem ser instalados em edifícios submetidos à excitação sísmica. Inicialmente é considerado apenas um único AMS instalado no topo do edifício e em seguida também são feitas simulações com múltiplos AMSs (MAMS), e por fim são descartados os AMSs desnecessários, obtendo assim a melhor resposta da estrutura. Para tanto, uma rotina computacional é desenvolvida em MatLab usando o método de integração direta das equações de movimento de Newmark para determinar a resposta dinâmica da estrutura. Para fins de análise podem ser considerados tanto sismos reais quanto artificiais. Os acelerogramas artificias são gerados a partir do espectro proposto por Kanai e Tajimi. Primeiramente, a estrutura é analisada somente com o seu amortecimento próprio para fins comparativos e de referência. Em seguida, a otimização do ou dos AMSs é feita, na qual a função objetivo é minimizar o deslocamento máximo no topo do edifício, e as variáveis de projeto, são a relação de massas (AMS - Estrutura), rigidez e amortecimento do ou dos AMSs. Para a otimização são utilizados os algoritmos Firefly Algotithm e Backtracking Search Optimization Algorithm. De acordo com as configurações do AMS, após a otimização dos seus parâmetros são determinadas as novas respostas dinâmicas da estrutura. Finalmente, pode-se observar que o método proposto foi capaz de otimizar os parâmetros do ou dos AMSs, reduzindo consideravelmente as respostas da estrutura após a instalação do mesmo, minimizando o risco de dano e colapso do edifício. Desta forma, este trabalho mostra que é possível projetar AMS e MAMS de forma econômica e eficaz. Currently, structures are being evaluated for a greater number of actions when compared to a few decades ago. This improvement in designing stage is happening because projects providing lightweight and slender structures, with lower implantation costs, are being more requested. Thus, evaluating structures not only subjected to static loads, but also to dynamic loads has become necessary. Dynamic loads acting on a structure are more damaging than static loads, if they are not well considered and dimensioned. Dynamic loads could occur from earthquakes, wind, equipment, movement of people or vehicles, among other sources, which cause vibrations in structures and may lead to a collapse. Tuned mass damper (TMD), a passive control device, can be installed as an alternative to reduce vibration amplitudes. TMD has several advantages, such as large capacity to reduce amplitude of vibration, easy installation, low maintenance, low cost, among others. Optimizing TMD parameters is fundamental for obtaining best cost-benefit relation, i.e., greater amplitude reduction along with lower number of dampers or lower mass. In this context, this study aims at proposing, through numerical simulation, a method for optimizing TMD parameters when installing them on buildings under seismic excitation. Initially, a single-TMD case is considered, then simulations with multiple-TMDs (MTMDs) are run; lastly, unnecessary TMDs are discarded, obtaining the best structural response. For this purpose, a computational routine is developed on MatLab using Newmark direct integration method for equations of motion to determine the dynamic structural response. Both real and artificial earthquakes are considered for purposes of analysis. Artificial accelerograms are generated from proposed Kanai-Tajimi spectrum. First, structure is analyzed only with its own damping for comparison and reference. Second, a single or multiple-TMD optimization is carried out, in which the objective function is to minimize the maximum displacement at the top of the building, and the design variables are modal mass ratio (Structure-TMD), stiffness and damping of a single or multiple-TMD. Firefly and Backtracking Optimization algorithms are used for optimization. According to TMD settings, new dynamic structural responses are determined after optimizing parameters. Finally, the proposed method could optimize parameters of single or multiple-TMDs, considerably reducing structural responses after their installation, minimizing the risk of damage and building collapse. Thus, this study shows the possibility of designing TMDs or MTMDs both economically and effectively.

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Tang, Ning. "Design of adjustable tuned mass dampers employing nonlinear elements." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/19727/.

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The work focuses on the design of the Tuned Mass Damper (TMD), targeted multi-mode, multi-directional vibrations of mechanical structures occurring over a wide temperature ranges. Extension of the target frequency range is achieved by making the devices adjustable, using components with nonlinear load-deflection behaviour. Two nonlinear components that are new in TMD design are studied, namely elastomeric O-rings and Tangled Metal Wire (TMW) particles. Evaluation of the performance of these devices on a typical engineering structure is carried out, and the feasibility of the proposed devices demonstrated. For the O-ring TMD, analytical models are developed to describe the load- deflection behaviour of the O-ring. An existing model for axial compression is improved while new models are established for shear and rocking deformations. Validation of the models is carried out using a specifically designed vibration test. Numerical models, aiming to estimate the elasticity of the O-rings with irregular cross-sectional shape, are developed and validated by comparison with the experimental results. The TMW particles seeks to address high temperature applications. The strong compression-dependent stiffness of these particles provides the basis for an adjustable TMD. Although there is some variation in the stiffness and damping for different collections of particles with similar physical properties, uniformity in- creases after several test runs. According to the assumptions of the equivalence of the TMW materials and the hyperelastic solid, a semi-empirical analytical model is developed and validated using experimental results. A novel design optimisation algorithm, based on the complex power approach, developed to provide an alternative route for the TMD involving nonlinear elements. The proposed route, involving the use of the a numerical, evolutionary search method, is finally applied to the design of a nonlinear TMD.

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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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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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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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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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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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Lindh, Cory W. "Dynamic range implications for the effectiveness of semi-active tuned mass dampers." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57884.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (p. 159-164). The response of tall buildings subjected to dynamic wind loads has been widely studied. For excitations approaching the resonant frequencies of the structure, ensuring serviceability is a significant concern. One traditional solution is the implementation of a tuned mass damper (TMD), which acts as a passive damping device in the region of the tuned frequency. However, TMDs exhibit a limited bandwidth and often require a significant mass. Active systems, such as the active mass driver, have been utilized to improve the effectiveness of the TMD concept, but these systems require significant power and bring the inherent risk of instability. Hybrid semi-active schemes with variable damping devices have been proposed. They are stable, require low power, and are controllable, thus providing a broader range of applicability. The concept of a semi-active tuned mass damper (STMD) has been investigated, but the influence of the dynamic range of the semi-active damping device has not been documented. This analysis assesses the effectiveness of STMD systems using a variable-orifice damper and a magnetorheological damper with varying dynamic ranges. Results demonstrate a performance dependence on the dynamic range and also elucidate the superiority of non-linear damping devices. It is shown that the prescribed TMD mass may be reduced by a factor of two when semi-active control is implemented, thereby making the STMD an attractive and feasible option when space and weight concerns govern design. by Cory W. Lindh. S.M.

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Verdirame, Justin Matthew 1978. "Design of multi-degree-of-freedom tuned-mass dampers using perturbation techniques." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/89918.

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Pallucco, Eleonora. "Controllo della risposta dinamica di un telaio mediante “Pendulum Tuned Mass Dampers - PTMD”." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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In questa tesi, inizialmente, sono stati affrontati questioni relative alla formulazione matematica dei pendoli: in particolar modo allo sviluppo dell’analisi matriciale che concerne i vari casi considerati sia in via teorica, che in quella pratica. Studiando i vari casi in via teorica, si è visto che l’applicazione del PTMD migliora notevolmente la risposta dei telai; mentre in via pratica, essendoci molte più incertezze ed irregolarità nei vari materiali e nei collegamenti tra di essi, in alcuni casi si riesce a vedere il miglioramento delle risposte solo attraverso gli andamenti degli accelerometri, e quindi solo attraverso PC; altri anche visivamente, come per il caso del telaio ad 1GdL alto 0,60 m.

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Aydan, Goksu. "Ride Comfort Improvement By Application Of Tuned Mass Dampers And Lever Type Vibration Isolators." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12612131/index.pdf.

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In this study, the efficiency of linear and rotational tuned mass dampers (TMD) and lever type vibration isolators (LVI) in improving ride comfort is investigated based on a vehicle quarter-car model. TMDs reduce vibration levels by absorbing the energy of the system, especially at their natural frequencies. Both types of TMDs are investigated in the first part of this study. Although linear TMDs can be implemented more easily on suspension systems, rotational TMDs show better performance in reducing vibration levels since, the inertia effect of rotational TMDs is higher than the linear TMDs. In order to obtain better results with TMDs, configurations with chain of linear TMDs are obtained in the second part of the study without changing the original suspension stiffness and damping coefficient. In addition to these, the effect of increasing the number of TMDs used in the chain configuration is investigated. Results show that performance deterioration at lower frequencies than wheel hop is reduced by using chain of TMDs. In the third part of this study, various configurations of LVIs with different masses are considered and significant attenuation of vibration amplitudes at both body bounce and wheel hop frequencies is achieved. Results show that TMDs improve ride comfort around wheel hop frequency while LVIs are quite efficient around body bounce frequency. Finally, parameter uncertainty due to aging of components and manufacturing defects are investigated.

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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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Demetriou, Demetris. "Enhancing the practical applicability of smart tuned mass dampers in high-rise civil engineering structures." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19285/.

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The ability of bones to concentrate material where the body needs most of its strength and the ability of trees to spread roots in search of moisture rich locations are only a few amongst the many examples of nature’s way of building adaptive “structures”. Even though civil engineering structures often appear inefficient, static and cumbersome, a new era of structural design aims to alter the status quo by mimicking nature’s way. This suggested adaptation process in civil structures often takes the form of passive, active and semi- active control. Through direct comparison of these methods, semi-active control is shown to combine the benefits of both active and passive systems and can be arguably considered the next step in improving dynamic structural performance; however the applicability of this exciting and novel for the structural engineering field technology, is not all-embracing. In order to enhance the development of this promising technology and contribute on the creation of a new era of “smart & thinking” structures that encompass an unconventional form of performance based design, this study aimed to develop enabling technologies and tools that enhance the selling strengths of semi-active and smart control using tuned-mass dampers. The original contributions to knowledge in this work are divided in three aspects. Firstly, the investigation of the influence of control algorithms on smart tuned-mass damper equipped high-rise structures, for which practical limitations have been taken into account. Leading to conclusion on the conditions for which each algorithm exhibits superior performance over the other. Secondly, the development of a fail-safe novel semi-active hybrid device configuration that enables performance gains similar to the active mass damper at considerably lower actuation and power demands. Finally, the development of a simple and robust at all gains control algorithm based on the modification of one of the most widely used controller in the engineering industry, namely the proportional-integral-derivative controller.

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Kourakis, Ioannis. "Structural systems and tuned mass dampers of super-tall buildings : case study of Taipei 101." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38947.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2007. Includes bibliographical references (leaves 68-69). The design of the first generation of skyscrapers was based on strength. Heavy masonry cladding and wall curtains used at that period added a considerable amount of stiffness and damping to the structure. Inter-storey drifts and peak accelerations were relatively small. Advances in the material science technology enabled the use of high-performance concrete, steel and composite sections. The former combined with the use of sophisticated 3-D structural design software packages resulted in the evolution of a new generation of more economical and structurally efficient skyscrapers. However, the increased flexibility and lower damping makes these structures more vulnerable to wind induced vibrations, causing severe human discomfort due to excessive accelerations. Several solutions have been engineered to mitigate the motions of Super-Tall buildings including structural, aerodynamic and auxiliary changes with the goal of increasing the inherent damping of the building. (cont.) The current thesis is comprised of three parts: a review of past and current trends in structural systems of tall buildings, including a comparison of the twenty tallest buildings globally; an investigation of passive control-Tuned Mass Dampers-with also several examples of structures which have such a system; and a demonstration of the effectiveness of Tuned Mass Dampers through a case study of the current tallest building to the structural top in the world, a 508m tremendous architectural, engineering and construction achievement - Taipei 101. The change in the response of the tower due to a wind-induced vibration is illustrated by performing a time-history analysis with and without the TMD in a SAP2000 model. Finally, recommendations for future research in the field of distributed TMDs are offered. by Ioannis Kourakis. M.Eng.

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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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Wenzel, Moritz. "Development of a Metamaterial-Based Foundation System for the Seismic Protection of Fuel Storage Tanks." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/256685.

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Metamaterials are typically described as materials with ’unusual’ wave propagation properties. Originally developed for electromagnetic waves, these materials have also spread into the field of acoustic wave guiding and cloaking, with the most relevant of these ’unusual’ properties, being the so called band-gap phenomenon. A band-gap signifies a frequency region where elastic waves cannot propagate through the material, which in principle, could be used to protect buildings from earthquakes. Based on this, two relevant concepts have been proposed in the field of seismic engineering, namely: metabarriers, and metamaterial-based foundations. This thesis deals with the development of the Metafoundation, a metamaterial-based foundation system for the seismic protection of fuel storage tanks against excessive base shear and pipeline rupture. Note that storage tanks have proven to be highly sensitive to earthquakes, can trigger sever economic and environmental consequences in case of failure and were therefore chosen as a superstructure for this study. Furthermore, when tanks are protected with traditional base isolation systems, the resulting horizontal displacements, during seismic action, may become excessively large and subsequently damage connected pipelines. A novel system to protect both, tank and pipeline, could significantly augment the overall safety of industrial plants. With the tank as the primary structure of interest in mind, the Metafoundation was conceived as a locally resonant metamaterial with a band gap encompassing the tanks critical eigenfrequency. The initial design comprised a continuous concrete matrix with embedded resonators and rubber inclusions, which was later reinvented to be a column based structure with steel springs for resonator suspension. After investigating the band-gap phenomenon, a parametric study of the system specifications showed that the horizontal stiffness of the overall foundation is crucial to its functionality, while the superstructure turned out to be non-negligible when tuning the resonators. Furthermore, storage tanks are commonly connected to pipeline system, which can be damaged by the interaction between tank and pipeline during seismic events. Due to the complex and nonlinear response of pipeline systems, the coupled tank-pipeline behaviour becomes increasingly difficult to represent through numerical models, which lead to the experimental study of a foundation-tank-pipeline setup. Under the aid of a hybrid simulation, only the pipeline needed to be represented via a physical substructure, while both tank and Metafoundation were modelled as numerical substrucutres and coupled to the pipeline. The results showed that the foundation can effectively reduce the stresses in the tank and, at the same time, limit the displacements imposed on the pipeline. Leading up on this, an optimization algorithm was developed in the frequency domain, under the consideration of superstructure and ground motion spectrum. The advantages of optimizing in the frequency domain were on the one hand the reduction of computational effort, and on the other hand the consideration of the stochastic nature of the earthquake. Based on this, two different performance indices, investigating interstory drifts and energy dissipation, revealed that neither superstructure nor ground motion can be disregarded when designing a metamaterial-based foundation. Moreover, a 4 m tall optimized foundation, designed to remain elastic when verified with a response spectrum analysis at a return period of 2475 years (according to NTC 2018), reduced the tanks base shear on average by 30%. These results indicated that the foundation was feasible and functional in terms of construction practices and dynamic response, yet unpractical from an economic point of view. In order to tackle the issue of reducing the uneconomic system size, a negative stiffness mechanism was invented and implemented into the foundation as a periodic structure. This mechanism, based on a local instability, amplified the metamaterial like properties and thereby enhanced the overall system performance. Note that due to the considered instability, the device exerted a nonlinear force-displacement relationship, which had the interesting effect of reducing the band-gap instead of increasing it. Furthermore, time history analyses demonstrated that with 50% of the maximum admissible negative stiffness, the foundation could be reduced to 1/3 of its original size, while maintaining its performance. Last but not least, a study on wire ropes as resonator suspension was conducted. Their nonlinear behaviour was approximated with the Bouc Wen model, subsequently linearized by means of stochastic techniques and finally optimized with the algorithm developed earlier. The conclusion was that wire ropes could be used as a more realistic suspension mechanism, while maintaining the high damping values required by the optimized foundation layouts. In sum, a metamaterial-based foundation system is developed and studied herein, with the main findings being: (i) a structure of this type is feasible under common construction practices; (ii) the shear stiffness of the system has a fundamental impact on its functionality; (iii) the superstructure cannot be neglected when studying metamaterial-based foundations; (iv) the complete coupled system can be tuned with an optimization algorithm based on calculations in the frequency domain; (v) an experimental study suggests that the system could be advantageous to connected pipelines; (vi) wire ropes may serve as resonator suspension; and (vii) a novel negative stiffness mechanism can effectively improve the system performance.

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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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SAINI, JASPAL SINGH. "EFFECT OF NONLINEARITIES DUE TO GEOMETRY, CABLES AND TUNED MASS DAMPERS ON THE ANALYSIS OF CABLE-STAYED BRIDGES." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1172770822.

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Czarnobay, André da Silva. "Estudo em túnel de vento dos efeitos de atenuadores dinâmicos sintonizados em modelos de edifícios altos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/13475.

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Com a crescente necessidade de projetos cada vez mais econômicos, bem como a valorização dos terrenos nos grandes centros urbanos, que leva a conseqüente necessidade de aumentar o aproveitamento destes, e com o desenvolvimento das técnicas construtivas e dos processos de análise estrutural, as edificações tornaram-se mais altas, leves, flexíveis, menos amortecidas, e, portanto, mais susceptíveis a problemas de vibrações, inclusive as induzidas pela ação do vento. Nessa situação, o amortecimento natural da edificação pode tornar-se insuficiente para reduzir os movimentos causados pela ação do vento, o que pode gerar desconforto aos usuários, quebra de vidros e até mesmo danos à estrutura. Para se atingir a redução destes deslocamentos, em alguns casos, requer-se um suplemento adicional de amortecimento, para evitar tais movimentações excessivas. Tal suplemento de amortecimento é alcançado pela instalação de um sistema de dissipação de energia na edificação. Os atenuadores dinâmicos sintonizados constituem-se em um destes sistemas de dissipação de energia, sendo utilizados para aumentar o amortecimento geral do sistema estrutural. Foram realizados testes com um modelo do edifício alto padrão “CAARC Standard Tall Building”, primeiramente sem nenhum atenuador e após com dois tipos de atenuadores com características diferentes instalados no modelo. No trabalho são apresentados e discutidos os resultados dos ensaios, realizados no Túnel de Vento Professor Joaquim Blessmann, da Universidade Federal do Rio Grande do Sul. Os atenuadores dinâmicos sintonizados (amortecedores de massa) mostraram-se eficazes na redução das vibrações transversais por desprendimento de vórtices, validando o túnel de vento como ferramenta de projeto para a prevenção e controle de fenômenos associados às vibrações induzidas pelo vento. With the increasing need of more economic buildings, as well as the great valorization of the terrains in the center of big cities, which leads to a consequent need to improve the utilization of this terrains, and with the development of the construction techniques and of the structural analysis process, the buildings have become higher, lighter, more flexible and less damped, and, therefore, more susceptible to problems of vibrations, such as those induced by wind action. On this new situation, the natural damping of the building could become insufficient to reduce the motion caused by wind action, which can lead to discomfort to the users, break of glasses and even damage to the structure. In order to obtain a reduction on this displacements, in some cases, an additional supply of damping is needed, to avoid this excessive movements. This supply of damping is obtained by the installation of an energy dissipation system on the building. The tuned mass dampers constitute on one of this systems of energy dissipation, being used to improve the overall damping of the structural system. Tests with a model of the “CAARC Standard Tall Building” were conduced, first with no damper attached to it, and then with two different types of tuned mass dampers installed on the model in each time. The results obtained with these tests, conduced on the Túnel de Vento Professor Joaquim Blessmann, at the Universidade Federal do Rio Grande do Sul are presented and discussed. In the tests, the tuned mass dampers have shown good efficiency in the reduction of the transversal vibration caused by vortex shedding, which validates the wind tunnel as a design tool for the control and prevention of the phenomena of wind-induced vibrations.

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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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Su, Yu Hung, and 蘇宇宏. "Floor Vibration Control Using Multiple Tuned Mass Dampers." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/05912340783298004772.

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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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Dorcena, Johane, and 杜瑟娜. "Vibration Reduction of Footbridges Using Multiple Tuned Mass Dampers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/65060095201554755881.

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碩士 國立中興大學 土木工程學系所 105 As the pedestrian bridge conception, from now, expands more in the length span whereas the cross section becomes slender and simple, multi-mode coupled vibrations occur frequently. The footbridge, a slim structure, becomes more sensitive to vibration effect. It is clearly understood that the vibration could be a problem. The users of this public facility should be comfortable while using it. Some endeavors have been done to lessen the vibration that is additional stiffness to the given devices. The most optimistic method to reduce vibration and improve the footbridge dynamic characteristics is Multiple Tuned Mass Dampers (MTMD). This study covers vibration reduction of footbridge using Multiple Tuned Mass dampers. The Footbridge is modeled and simulated numerically using the commercial structural analysis and design software (SAP2000) to perform dynamic responses due to pulsating stationary, moving and uniform loadings. A comprehensive Optimization method is introduced to determine the optimal design parameters of MTMD system. The objective is to minimize footbridge responses and remove unacceptable requirements, such as peak and root mean square (RMS) acceleration. Numerical analysis shows that the proposed MTMD designed by the annealing optimization procedure is effective in reducing dynamic response during crowd–footbridge resonance.

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Shih, Liang-Kang, and 史樑康. "Practical Analysis and Design of Viscous Dampers Installed in Multiple Tuned Mass Dampers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/x8eu7e.

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碩士 國立中興大學 土木工程學系所 104 To provide damping, we have to installed viscous dampers on MTMD. But the MTMD installed on long period structure has characteristics of long stroke and period, and viscous dampers must have longer stroke to satisfy MTMD causing difficulties of manufacture. The main target in this research is reducing stroke of VD by installed angle, and provide design damping coefficient. First we will discuss the nonlinear problems about installed angle and compare different angle of installation with structural control. Then we will discuss about nonlinear VD with installed angle and effects of strcture response caused by velocity index. And compare results with linear VD. By the results of numerical analysis the stroke of VD can be efficiently decreased by the design and installation in this research and slightly changed structural response. The result can make the internal abilities about design, manufacture, and installation of TMD/MTMD completely.

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Kundu, Parmananda. "Vibration control of frame structure using multiple tuned mass dampers." Thesis, 2012. http://ethesis.nitrkl.ac.in/3919/1/VIBRATION_CONTROL_OF_FRAME_STRUCTURE_USING_MULTIPLE_TUNED_MASS_DAMPERS.pdf.

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Need for taller structure in construction and real estate industry is increasing all over the world. These structures are flexible and constructed as light as possible (as seismic load acts on a structure is a function of self-weight), which have low value of damping, makes them vulnerable to unwanted vibration. This vibration creates problem to serviceability requirement of the structure and also reduce structural integrity with possibilities of failure. Current trends use several techniques to reduce wind and earthquake induced structural vibration. Passive tuned mass damper (TMD) is widely used to control structural vibration under wind load but its effectiveness to reduce earthquake induced vibration is an emerging technique. Here a numerical study is proposed on the effectiveness of tuned mass damper to reduce translation structural vibration. Total three type of models, i.e., shear building with single TMD, 2D frame with single TMD and 2D frame with double TMD are considered. Total five numbers of loading conditions are considered named sinusoidal ground acceleration, EW component of 1940 El-Centro earthquake (PGA=0.2144g), compatible time history as per spectra of IS-1893 (Part -1):2002 for 5% damping at rocky soil (PGA=1.0g), Sakaria earthquake (PGA=1.238g), The Landers earthquake (1992) (PGA=1.029g) for time history analysis of considered model.The effectiveness of single TMD to reduce frame vibration is studied for variation of mass ratio of TMD to frame. Also the effect of double tuned mass damper on the frame response is studied for uniform, non uniform distribution of mass ratio and variation of damping ratio of damper.From the study it is found that effectiveness of TMD increases with increase in mass ratio. Use of double TMD is much more effective than single TMD of same mass ratio for vibration mitigation under earthquake as well as sinusoidal acceleration.

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Elias, Said. "Effective placement and tuning of multiple tuned mass dampers for mitigation of vibrations in structures." Thesis, 2017. http://localhost:8080/iit/handle/2074/7467.

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Lung, Hao-Yu, and 龍豪佑. "Component Design, Manufacture and Shaking Table Test of Multiple Tuned Mass Dampers." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/2u6n34.

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碩士 國立中興大學 土木工程學系所 101 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. The main reason is lacking of the experience in designing and manufacturing a full scale TMD. According to these reasons, an automatic optimal MTMD design program is firstly developed based on the MTMD theory. Then, the manufacture procedure of the MTMD components and practical considerations to implement in a real building are developed. Finally, a scale-down long period MTMD system is manufactured and tested via a shaking table. Test test result is agree with the theoretical model. This study shows the domestic technology does have the ability to design and manufacture the MTMD system for the vibration reduction of high-rise buildings.

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Yung-Sheng, Hsu, and 許永聖. "A study on vibration reduction of structures using multiple tuned mass dampers." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/85831523883832749661.

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碩士 國立高雄海洋科技大學 輪機工程研究所 94 The object of this thesis is to investigate the vibration reduction effectiveness of MTMD (Multiple Tuned Mass Dampers). First of all, the governing equations for the entire vibrating system (i.e., the single degree-of-freedom spring-mass-damper main system installed with a MTMD) and the expression for calculating the dynamic magnification factor of the spring-mass-damper main system are derived. Then, based on the last expression of dynamic magnification factor, the influence of MTMD parameters (e.g. mass ratio, frequency ratio, frequency spacing, etc.) on its vibration reduction effectiveness is studied. Next, by replacing the single degree-of-freedom spring-mass-damper main system with a multiple degree-of-freedom beam-typed (or plate-typed) structures, the influence of MTMD parameters on its vibration reduction effectiveness is further investigated. From the presented numerical results, it can be found that the MTMD parameters affect its vibration reduction effectiveness significantly.

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chen, Shih-feng, and 陳士峰. "Practical considerations of Multiple Tuned Mass Dampers for Vibration Reduction of Buildings." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/65161610683333220207.

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碩士 國立中興大學 土木工程學系所 103 Vibration control of civil engineering structures using tuned mass dampers (TMDs) is a widely accepted control strategy after numerous analytical and experimental verifications. Firstly, a finite element model of an in planning high-rise building was built by a commercial structural analysis software, i.e., ETABS. Optimal parameters of the multiple TMD (MTMD) was designed based on the dynamic parameters of the target building. The structural responses with and without MTMD system was then compared. The results show that the MTMD system is effective in vibration reduction. Furthermore, the full scale MTMD system and the related supporting components on the installation floor were also designed to guarantee the functions of the MTMD system. This study is helpful to the application of the MTMD system in high-rise buildings.

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Zheng, Yi-Kai, and 鄭亦凱. "Multiple Tuned Mass Dampers for Reduction of Floor Vibration Due to Human Activities." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/74398303905210722743.

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碩士 國立中興大學 土木工程學系所 105 Resonant responses of a large-span floor occur when the frequencies of human-induced excitation are close to the dominant frequencies of the floor. Excessive floor acceleration and deformation will result in human discomfort, structural member fatigue, and even structural system failure. In this study, multiple tuned mass dampers (MTMD) are applied to reduce floor vertical vibration due to human activities to assure structural safety and serviceability. The dynamic equations of motion of a floor equipped with MTMD under external forces are derived. An optimal design method is proposed to determine the optimum numbers, locations, and system parameters of the MTMD system for the controlled modes based on the control algorithm the authors developed. A real gymnasium with large-span floor is investigated to examine its capability in resisting man-induced floor vibrations. First, the Stochastic Subspace Identification (SSI) method, an output only system identification technique, is used to identify the dominant modal frequencies, damping ratios, and mode shapes of the floor based on real vibration measurements. Then, the MTMD system is decided based on above design procedure. Moreover, the finite element model of the floor is updated by the identified modal parameters. Finally, the control effectiveness of the MTMD system is verified through the comparison of floor accelerations with and without MTMD system under human activity loadings and to meet the comfort levels of NBC1990 (National Building Code of Canada, NBC).

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Jian, Jie-Yong, and 簡捷永. "Practical Application of Multiple Tuned Mass Dampers for Vibration Suppression of Irregular Buildings." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/30460555185248380938.

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碩士 國立中興大學 土木工程學系所 105 A multiple tuned mass damper (MTMD) system composed of multiple units of tuned mass damper (TMD) and arranged in parallel is proposed to reduce the vibration of torsionally-coupled buildings due to environmental loadings like wind and earthquake. By attaching MTMD to a structure, the structural vibration energy can be transferred to the MTMD and dissipated via the damping mechanism. Compared with the conventional single TMD, the proposed MTMD system is more effective and robust in mitigating frequency detuning effect. This study deals with some practical design considerations such as the optimum location, moving direction and number of the MTMD system for a high-rise building with torsion coupling (TC) behavior. The control effectiveness of the MTMD system for the controlled mode was evaluated. The commercial structural analysis software, i.e. ETABS, was first applied to generate the finite element model of the target building and to analyze its TC behavior. Then, the number and optimum location (in plane and in elevation) of the MTMD system was determined based on the mode shape of the controlled mode. The optimal parameters of the MTMD system were calculated by an automatic program, which was based on the optimal design procedures developed by the authors. In order to evaluate the MTMD’s control performance, the dynamic responses of a building with MTMD were compared with those of the uncontrolled case under different excitations. The results show that the proposed MTMD system is effective in reducing the vibration of buildings with TC behavior.

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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.

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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.

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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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Hong, Yu-Shan, and 洪郁珊. "Optimal Design for Distributed Multiple Tuned Mass Dampers and the Performance under Excitation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/15044071402561047362.

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碩士 國立臺灣大學 土木工程學研究所 104 In recent year, tuned mass dampers have been widely used to control the vibrations due to wind or earthquake. TMDs are often used in high-rise buildings, long-span bridges and machines of high-tech factory to reduce the vibration and the discomfort. But the performance of single tuned mass damper (STMD) is sensitive to the frequency of TMD, it suffered a deterioration if the TMD parameters shift away from their optimum solution. Furthermore, the performance of system with TMD sometimes becomes worse when the system is affected by earthquakes. Some researchers point out that high modal responses may be excited when the system is suffered by earthquake. So the object of the distributed multiple tuned mass damper (DMTMD) is that not only control the first mode but also the other important modes. It makes the vibration of system can always be controlled no matter what the excitation frequency is. In the thesis, we propose the design method of DMTMD, and respectively, give the STMD and the DMTMD appropriate algorithm. It makes the procedure of optimal analysis faster, more stable and more accurate, and the solutions are global minimum. Using the framework of this thesis, we do the parameter optimization on shear type structures of different story, and use the white-noise and earthquake time histories around the world to examine the performance of DMTMD. In reality, the axial deformation will occur when the structure suffered from earthquake. So we also use moment frame to analysis in order to get a reasonable solution.

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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.

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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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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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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.

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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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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.

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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.

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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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Chen, Yu-Jing, and 陳鈺靜. "Shaking Table Test of Electromagnetic Multiple Tuned Mass Dampers for Structural Control and Energy Harvesting." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/j59gpg.

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碩士 國立中興大學 土木工程學系所 106 With the development of construction technologies, high-rise buildings have sprouted almost everywhere in the world. The high slenderness feature of the buildings leads to problems of human comfort and structural safety. Tuned Mass Damper (TMD), such as the pendulum-typed TMD installed in Taipei 101, is one of the famous examples of structural control devices. However, it is bad that conventional TMDs used viscous damper to dissipate the vibration energy of TMD into waste heat. In addition, it is generally recognized that the detuning effect will significantly reduce the control performance of a single TMD. In this paper, an electromagnetic multiple-tuned mass damper (EM-MTMD) is proposed. By replacing the viscous damper with a DC motor and a transmission system, the vibration energy of the TMDcan be converted into electricity which can be saved for practical uses. The EM-MTMD has the dual functions of vibration control and energy harvesting and is a new type of green energy. In this study, a prototype of EM-MTMD system was designed and manufactured. A series of performance tests for the EM-MTMD system were first conducted on a shaking table. Then, the EM-MTMD was installed into a scaled-down structure with long period to simulate a high-rise building equipped with the EM-MTMD system. The test results show that the EM-MTMD can effectively reduce structural vibrations and generate electricity. The predicted results agree very well with the the experimental results showing the accuracy the analytical model.

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LI, JIE-CHUN, and 李杰春. "Optimal Design and Vibration Reduction Analysis of Series Multiple Tuned Mass Dampers for Asymmetric Buildings." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/29pr2z.

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碩士 國立聯合大學 土木與防災工程學系碩士班 107 A tuned mass damper (TMD) is a single-degree-of-freedom (SDOF) system, capable of suppressing the dynamic response of a certain structural mode. One of the essential features of TMD is that its frequency needs to be fine-tuned to maintain its vibration control effectiveness. MTMD (Multiple Tuned Mass Dampers) is an extension of TMD. It is composed of multiple TMD units in parallel to form a band-width of the tuning frequency or to provide multiple tuning frequencies to various structural modes. Thus, an MTMD can be less sensitive to the frequency change than a TMD. Even so, both TMD and MTMD have high stroke demands for mass blocks, increasing difficulties in design and manufacture of its components of damping and resilience. The purpose of this master's thesis is to initiate a study on a new-type mass dampers, namely the Series Multiple Tuned Mass Damper (SMTMD), comprising of serially interconnected multi-degree-of-freedom TMDs. In this master's thesis, SMTMDs for response control of multi-story buildings with torsionally coupled (TC) effect due to two-way eccentricity of centre of rigidity from the centre of mass of floor were studied. A design theory was developed for the optimization of the SMTMD parameters. Considering the features of floor response of TC buildings, the performance of SMTMD was measured by indices that were established with more than one significant vibration modes of the primary structures. The total mass of SMTMD was assumed to be linearly distributed to each TMD unit with a mass-distribution factor. Both uniform and variant TMD damping and stiffness coefficients were considered. The characteristic and corresponding performance of optimal SMTMD under various parametric conditions were investigated and compared with those of the single TMD. The optimal location of SMTMD on the floor was also investigated. It concludes that an SMTMD is capable of reducing the TC response of multiple modes, while more than one TMD are needed to achieve the similar control effectiveness.

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Liu, Chi-Feng, and 劉吉豐. "Optimal Design and Comparison of Multiple Tuned Mass Damper." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/86006769197010464320.

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碩士 國立中興大學 土木工程學系所 96 Multiple tuned mass dampers (MTMD) are structure control systems that composed by many masses, dampers and springs. The purpose of MTMD is to make the natural frequency of MTMD tuned with that of the main structure for changing the dynamic characteristics of the main structure. MTMD can reduce the dynamic response and increase the safety and availability of the main structure. Many schemes for designing optimal parameters of MTMD have been proposed and developed very well. However, there are few researches compare and analyze the difference among these schemes. Therefore, this thesis shall propose a new optimal parameter design scheme and compare the proposed scheme with two well developed schemes, Igusa and Xu’s scheme and Lin and Yang’s scheme. We will discuss the results of structural vibration control, time complexity and practical among the three schemes. The thesis can help us to understand the shortcomings and advantages of these three schemes.

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Chiu, Kuo-Cheng, and 邱國誠. "Sensitivity Analysis and Solution to Frequency Detuning Effect on Control Performance of Multiple Tuned Mass Dampers." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/9m6nkw.

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碩士 國立中興大學 土木工程學系所 101 It is found that the control efficacy of a multiple tuned mass damper (MTMD) may significantly degrade when TMD’s frequency does not tune to its desired value. Frequency detuning usually results from the uncertainties of structural systems such as modeling and parameter identification errors. In this study, the frequency detuning effect due to the variation of controlled system parameters on the control performance of MTMD is investigated. A sensitivity analysis is carried out to determine the optimal system parameters of a MTMD and to evaluate its control effectiveness. Optimal design procedure for MTMD with the consideration of frequency bandwidth is proposed to alleviate the detuning effect. Three kinds of frequency distribution methods are compared in this study, including optimal arbitrary distribution, uniform distribution and linear distribution. Three distribution methods are designed to have the same damping and stiffness coefficients with different mass. A SDOF system and a three-story building are applied to verify the applicability and efficacy of the proposed optimal MTMD design method. It is proved that the proposed new optimum design procedure is useful and applicable to enhance the robustness of MTMD.

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Gkaras, Vasileios. "Vibration isolation systems using hysteretic multiple tuned mass damper oscillators." Thesis, 2008. http://hdl.handle.net/1911/22152.

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The subject of this study is the vibration isolation effect of linear and nonlinear hysteretic single degree of freedom oscillators attached to a structure. The system of oscillators, attached to the main structure, reduce the amplitude of its structural response, over a wide frequency band excitation. This is achieved by distributing the natural frequencies of the attachments over an a priori specified frequency interval, which is related to the excitation power spectrum density. In order to introduce hysteretic restoring force to the oscillators and study its effect to the vibration reduction on the main structure the Bouc-Wen differential model of hysteresis is used. The introduction of hysteresis to the oscillators is observed to increase the vibration isolation efficiency of the attachments in certain cases. The study of the vibration isolation system behavior is conducted using the Monte Carlo technique. An explicit matrix formulated Newmark integration scheme is used for the linear attachment case. In the case of hysteretic attached oscillators, the system of equations of motion is integrated by an iterative decoupled Newmark integration technique both for the computation of the restoring force as well as the total response of the system. This scheme improves significantly the efficiency of the numerical integration of the equations of motion and accelerates the computational intensive Monte Carlo method. Further, statistical linearization of the hysteretic system is conducted. The agreement of the statistics of the nonlinear system response computed by the Monte Carlo method with those computed by the statistical linearization method enables the use of the latter as an efficient method for the computation of the nonlinear system response statistics in the frequency domain.

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Yang, Cheng-Wen, and 楊正文. "Comparative Study of Designed Parameter of Multiple Tuned Mass damper." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/72863649254947077078.

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碩士 國立中興大學 土木工程學系所 94 The thesis deals with the comparison of three types of multiple tuned mass damper (MTMD) design for a shaking-table test building to choose the most practical design method with the consideration of economical and vibration control effectiveness. With the same total MTMD mass, the first type is to assign each MTMD substructure to has the same mass and damping ratio, and to let the MTMD frequencies being uniform distributed. For the second type, each MTMD substructure has the same mass and damping ratio but independent frequency ratio. As to the third type, each MTMD substructure has the same damping and stiffness coefficients with independent frequency ratio, which results in different MTMD substructure mass. Because the spring and damper can be identical, the third type design becomes more practical than the others. Using the three-story steel structure model in the National Center for Research on Earthquake Engineering, the optimal MTMD parameters of the three types were calculated and the analysis of MTMD vibration control effectiveness was performed numerically. It is shown that the three type MTMDs have almost the similar control efficiency, which can be validated through the shake table test in the future.

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Lin, Chun-Chang, and 林春長. "Multiple Tuned Mass Damper-Aided Base Isolation for Military Equipments Against Blast Loadings." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99001547823723060605.

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碩士 國立中興大學 土木工程學系 93 The main purpose of this thesis is to investigate the vibration control effectiveness of a base isolation system combined with multiple tuned mass dampers (MTMD) for military equipments under blast loading. A finite element analysis program, named LS-DYNA, is used to simulate the ground acceleration due to the explosion of a specific amount of TNT. Moreover, the Fourier spectrum of the explosive wave is also discussed. Because the dominant frequency of an general explosion wave is high, a base isolation is employed to enlarge the fundamental period of military equipment so that the input energy from the explosion wave can be reduced. To prevent the base-isolated system from the low-frequency resonance with an earthquake, a MTMD system is installed at the based-isolated level. In this study, the MTMD optimal design parameters are determined by minimizing the first modal mean-square response of the base-isolated system. From the numerical verifications, it is evident that the MTMD is useful on reducing the dynamic response of base-isolated military equipments under earthquakes and will not generate the side effect of acceleration amplification like a high-damped system under a high-frequency blast loading.

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Huang, Qi-Hong, and 黃啟宏. "Dynamic Parameter Extraction of Multiple Tuned Mass Dampers and Primary Structure based on Vibration Measurements of the Combined Building-MTMD System." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/27087995932728436436.

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碩士 國立中興大學 土木工程學系所 102 In this thesis, a methodology is develped to extract the dynamic parameters of multiple tuned mass dampers (MTMD) and the primary structure itself from the dynamic response measurements of the combined primary building-MTMD system. MTMD is composed of a number of TMDs and its control effectiveness is achieved by arranging these TMDs to have an appropriate frequency distribution around the controlled mode of the primary building. Therefore, it is important to know the parameters of the primary structure as well as the MTMD to ensure the tunning condition. In practical, an MTMD set may be assembled in-situ along with the construction of a building. In such a case, the dynamic properties of the MTMD device and the building cannot be tested individually. For this purpose, a methodology is developed based on the eigen-parameters of any two complex modes of the combined building-MTMD system. By means of the theoretical derivation in state-space, the non-classical damping feature of the system is characterized. It can be combined with a system identification technique as a procedure to achieve the goal on the basis of acceleration measurements of the building-MTMD system. The proposed procedure was verified numerically and experimentally. Both results show that the procedure is able to extract parameters of the MTMD and the primary building, and it is useful for MTMD implementation practices.

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