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1
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
2
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.
3
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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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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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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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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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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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 levelssince, 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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Andreotti, Roberto. "Dissipative replaceable components and impact mass dampers towards more resilient earthquake-resistant steel structures." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/347239.
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This thesis work deals with the passive control of the dynamic response of steel buildings against earthquakes. To provide easy repairability after an earthquake and mitigate internal actions different activities are pursued: i) hybrid simulations (HSs) of full-scale steel and steel-concrete composite frames endowed with dissipative replaceable components, and ii) development of an innovative system for seismic vibration mitigation based on impact mechanism. The aforementioned research issue is approached at two levels. The former level is based on the contribution to the European funded RFCS Dissipable project, that aims at promoting the employment of dissipative replaceable components into common design practice. In the context of performance-based earthquake engineering (PBEE), this is achieved by
means of full-scale HSs on steel and steel-concrete composite frames equipped with specific seismic components that allow for the assessment of their dissipative behaviour and their replaceability easiness. In particular, innovative frames equipped with two different components are examined: namely, the dissipative replaceable beam splices (DRBeS) and the dissipative replaceable braced connections (DRBrC). The whole experimental activity is approached at the system level, which allowed for the HS of six-storey full-scale frames by physically realizing only their first floors, while numerically simulating the remainder of the structures. Physical and numerical substructures were coupled by means of electro-hydraulic actuators, that controlled the displacements of the physical substructure, while a real-time numerical algorithm generated the displacement command accounting for a time scaling factor. Within the PBEE approach and to assess the performance of the aforementioned dissipative components, HSs at damage limitation (DL), significant damage (SD) and near collapse (NC) limit states were carried out. Given the design limit states, the dissipative replaceable components successfully protected the parts of the frames that had to remain elastic according to the capacity design; to dissipate a large amount of energy, instead, the ductile components activated wide and stable hysteretic behaviours. The frames behaved as foreseen and the comparison with the predictions of the reference numerical models shows favourable comparisons. Moreover, the passive damaged components were replaced without any particular difficulty. The latter activity is also conceived in the context of passive structural control. Along this main vein and with the purpose of mitigating seismicinduced structural vibrations, an impact mass damper (IMD) was conceived and developed. The device is constituted by a mass installed on the top of a building, which is free to move along a linear path and impacts against two stoppers. The impact mechanism forces the controlled structure to be subjected to impulsive forces that, given their high frequency content, are able to transfer energy to the higher modes of vibration; these modes are mainly associated with lower participant masses and higher damping coefficients: in such instances, the design is challenging. More precisely, the foreseen damping system is controlled by three different parameters: the gap between the mass and the stoppers, the coefficient of restitution and the mass of the impacting body, respectively. To optimize such parameters due the stochastic seismic input, a relevant procedure is set by means of the design of experiments and the Kriging surrogate model. Relevant results show how the optimized parameters permit an effective vibration mitigation of the controlled system. Finally, a systematic comparison of the dynamic response of different steel frames, shows how short-period structures are more suitable to be seismically protected by specially-designed IMDs.
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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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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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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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Mazza, Samuele. "Soluzioni progettuali con dissipatori viscosi per il miglioramento sismico di un edificio ospedaliero." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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Nel presente elaborato si sono analizzate alcune metodologie per il miglioramento sismico dell'Istituto Ortopedico Rizzoli. In particolare sono state elaborate tre differenti soluzioni progettuali contemplanti i dispositivi di smorzamento viscoso. Le soluzioni si diversificano oltre che dal punto di vista applicativo, anche da quello teorico, in quanto gli smorzatori in una soluzione sono stati inseriti all'interno della costruzione stessa venendo quindi modellati in modo proporzionale alle masse di piano, nelle altre due soluzioni sono inseriti al di fuori della struttura, costituendo alcune torri esterne a complemento del progetto di miglioramento; in quest'ultimo caso i dispositivi vengono modellati proporzionalmente alle rigidezze laterali degli elementi verticali interpiano. Il dimensionamento degli smorzatori è stato effettuato seguendo i criteri proposti nella Five-Step Procedure proposta da Silvestri et al. nel 2010. Per ogni soluzione, si è redatto il corrispondente computo metrico estimativo al fine di confrontare i costi delle tre soluzioni.
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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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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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Grenat, Clément. "Nonlinear Normal Modes and multi-parametric continuation of bifurcations : Application to vibration absorbers and architectured MEMS sensors for mass detection." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI078/document.
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Un des buts de cette thèse est d’approfondir la compréhension de la dynamique non-linéaire, notamment celle des MEMS, en proposant de nouvelles méthodes d’analyse paramétrique et de calcul de modes normaux non-linéaires. Dans une première partie, les méthodes de détection, de localisation et de suivi de points de bifurcation selon un unique paramètre sont rappelées. Ensuite, une nouvelle méthode d’analyse multiparamétrique basée sur la continuation récursive d’extremums est présentée. Cette méthode est ensuite appliquée à un absorbeur de vibration non-linéaire afin de repousser l’apparition de solutions isolées. Deuxièmement, une méthode de calcul de modes normaux non-linéaires est présentée. Une condition de phase optimale et une régularisation de l’équation de mouvement sont proposées afin d’obtenir une méthode de continuation plus robuste au niveau des interactions modales. Ensuite, un problème quadratique aux valeurs propres modifié pour le calcul de stabilité et de points de bifurcation est présenté. Finalement, le calcul de modes normaux non-linéaires a été étendu aux systèmes non-conservatifs permettant la continuation des résonances d’énergie en déplacement et des résonances de phase. Troisièmement, la dynamique non-linéaire de réseaux de MEMS basé sur plusieurs micro-poutres résonantes est analysée à l’aide des méthodes proposées. Tout d'abord, un phénomène de synchronisation de points de bifurcations dû au couplage électrostatique dans les réseaux de MEMS est expliqué. Puis, la dynamique non-linéaire d'un réseau dissymétrisé par l'ajout d'une petite masse sur une micro-poutre est analysée. Enfin, des mécanismes de détection de masse exploitant ces phénomènes non-linéaires sont présentésOne of the goals of this thesis is to enhance the comprehension of nonlinear dynamics, especially MEMS nonlinear dynamics, by proposing new methods for parametric analysis and for nonlinear normal modes computation. In a first part, methods for the detection, the localization and the tracking of bifurcation points with respect to a single parameter are recalled. Then, a new method for parametric analysis, based on recursive continuation of extremum, is presented. This method is then applied to a Nonlinear Tuned Vibration Absorber in order to push isolated solutions at higher amplitude of forcing. Secondly, a method is presented for the computation of nonlinear normal modes. An optimal phase condition and a relaxation of the equation of motion are proposed to obtain a continuation method able to handle modal interactions. Then, a quadratic eigenvalue problem is shifted to compute the stability and bifurcation points. Finally, nonlinear normal modes are extended to non-conservatives systems permitting the continuation of phase and energy resonances. Thirdly, the nonlinear dynamics of MEMS array, based on multiple resonant micro-beams, is analyzed with the help of the proposed methods. A frequency synchronization of bifurcation points due to the electrostatic coupling is discovered. Then, the nonlinear dynamics of a MEMS array after symmetry breaking event induced by the addition of a small mass onto one of the beam of the array is analyzed. Finally, mass detection mechanisms exploiting the discovered phenomena are presented
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Rao, Nimisha 1979. "Real time tuned mass damper simulation system." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/85733.
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Wu, Lyu-Syuan, and 吳律旋. "Parameter Analysis of Tuned-mass-dampers with Intrinsic Damper Installed on Stacks." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/pguk2j.
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碩士國立虎尾科技大學
航空與電子科技研究所
103
The research explores spring constant, damping coefficient and mass of damper parameter analysis of a structure of stack carrying a TDMD with arbitrary magnitudes were made by means of the analytical and numerical combined method (ANCM) and finite element method(FEM). The analysis of results in ANCM, the TDMD installs the location by the fixed port more approach free port, the natural frequency changes more big, gradually increase to the spring constant value, it the first natural frequency also gradually enlarge, but the second and the third natural frequency all have no change, camping coefficient value gradually increases, it the value decrement of first natural frequency is small, but the second and the third natural frequency all have no change, the analysis of results in FEM, spring constant, camping coefficient and mass magnitudes to its first, the second with the trend of third natural frequencies change trend with corresponding one obtained from analytical and numerical combined method.
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HU, ZHI-MING, and 胡志銘. "Seismic effectiveness of passive tuned-mass dampers." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/56155367697621241744.
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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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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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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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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.
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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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Roffel, Aaron J. "Condition Assessment of In-Service Pendulum Tuned Mass Dampers." Thesis, 2012. http://hdl.handle.net/10012/7083.
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Tuned mass dampers (TMDs) are auxiliary damping devices installed within tall structures to reduce undesirable wind-induced vibrations and to enhance the overall system damping and hence, the dissipative capacity. The design of TMDs involves the selection of optimal auxiliary mass, frequency, and damping, based on the main structure's mass, natural frequency and damping properties. TMDs are inherently susceptible to detuning, where the auxiliary parameters are no longer optimal due to deterioration or changes within the system, resulting in a degradation in their performance. In order to correct for this detuning, it is necessary to perform a condition assessment while the TMDs are in service. The main goal of this thesis is to present a methodology to conduct condition assessment while the TMDs are in service. The proposed methodology does not involve either restraining the TMD or providing controlled external excitation to the structure, and relies on ambient measurements only. The first phase in the condition assessment is to estimate the bare structure's modal properties using acceleration measurements obtained from the structure while the TMDs are unrestrained. The present work accomplishes this goal within the framework of parametric identification using Kalman filtering, where the unknown parameters (bare modal properties) are appended to the state vector and estimated. Unlike most of the literature on this subject, the noise statistics for the filter are not assumed to be known a priori. They are estimated from the measurements and incorporated into the filter equations. This filter involves direct feedthrough of the process noise in the measurement equation and the appropriate filter is derived and used following the noise covariance estimation step. In the next phase, criteria to assess the condition of the TMD are developed. They include optimal tuning parameters established using simulated experiments and measured equivalent viscous damping. The research considered pendulum tuned mass dampers (PTMDs), which presently account for a large fraction of full-scale applications. Results were demonstrated using numerical investigations, a bench-scale model equipped with an adaptive mechanism for adjusting auxiliary damper parameters, and a full-scale PTMD-equipped structure. The main contributions of this thesis are: (a) a broader understanding of the coupled biaxial behaviour of PTMDs has been developed; (b) a systematic procedure for estimating the underlying modal characteristics of the structure from ambient vibration measurements within the framework of Kalman filtering has been achieved; (c) a comprehensive framework to undertake condition assessment of TMDs has been presented, integrating parametric identification from measured response data and performance prediction for design period wind events using boundary layer wind tunnel studies. The work provided new insight into the design and behaviour of PTMDs and presented a comprehensive approach to quantify their performance. The Kalman filtering framework also provides an efficient platform to build adaptive passive tuned mass dampers that can be tuned in place and adjusted to correct for detuning and accommodate various operating conditions.
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ZENG, YONG-CANG, and 曾勇蒼. "Bridge With Tuned Mass Dampers To Vertical Seismic Excitation." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/16141072070781531006.
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Hsiao, Hsiang-Yu, and 蕭祥佑. "Optimal Design for Tuned Mass Dampers and Performance Comparison." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/65449442101645620604.
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碩士國立臺灣大學
土木工程學研究所
103
In recent years, tuned mass dampers have been adopted in high-rise building to reduce the vibration under wind forces. However, there are many researches discussing the reducing effect of different methods and forms of TMDs without considering the robustness. This study used a “composite index” to take both the effectiveness and robustness into consideration, and pointed out the improvements after using the penalty function and compared the TMDs in different forms, methods, and objective functions.Furthermore, the actual earthquake records were used to examine the result statistically in this study. Because the optimization method used in previous study is a gradient-based algorithm, optimal parameters could be the local minimum depending on the given initial conditions. This study used two algorithms to solve this problem thus making it more efficient to get the global minimum. Nevertheless, when the damping ratio of the main system is greater than zero, it is necessary to use the iteration method to obtain the optimal parameters. The equations we proposed to design the optimal TMD was calculated by using the regression method. In the researches, it is quite common to design the TMDs by using the shear type buildings or simplifying MDOF to SDOF rather than the real structure. Although it’s much easier and faster to solve the problem, they are still different from real structures, and this study also precedes to discuss the differences between them.
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Gau, Yung-Chao, and 高雍超. "Design Guidelines and System Identification with Tuned Mass Dampers." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/34607286356450006893.
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碩士國立中興大學
土木工程研究所
82
In this study, an optimum design guideline and system identification technique are developed to evaluate the modal parameters for a structure with TMD based only on partial response measurements (without the measurement of input excitation). First, a random decrement method is employed to reduce the measured response data to extract free vibration responses at each measured location due to initial displacement. Then, Ibrahim time domain technique is applied to calculate the modal frequencies, damping ratios and mode shapes. To obtain the complete mode shapes, an interpolation and iteration scheme are developed to calculate the mode shape value for the locations without measurement. All mode shapes obtained are mutually orthogonal and the structural seismic responses are also estimated.Based on the identified modal parameters, an optimum TMD is determined. Numerical examples of one-story, three-story, and five-story buildings with and without TMD are used to verify that the proposed system identification technique is able to identify structural dominant modal parameters and responses accurately even with small number of measurements and the noise-to-signal ratio up to 20%. Furthermore, the optimal design TMD is proved to be a useful control device.
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Chen, Yi Fan, and 陳毅帆. "Development of Fragility Curves of Buildings with Tuned Mass Dampers." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/71093103725896232769.
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碩士中華技術學院
土木防災工程研究所
96
The feasibility of the steel moment resisting frame building with a nonlinear tuned mass damper on the roof to increase its capacity is conducted in this research. The nonlinear behavior of the building simulated with two concentrated plastic hinges at the ends of beams and columns with Wen’s model. The bilinear model is adopted to simulate the nonlinear characteristics of the lead rubber bearings. The input ground motions are incorporated with a wide variety of ground accelerations: hanging walls, footwall, stiff site, medium site, and soft site. The records in Taipei basin from two different source mechanisms, the 1999 Chi-Chi earthquake and the 2002 Huolian earthquake, are included in the nonlinear time history analysis. The nonlinear tuned mass damper can effectively reduce the drift ratio of buildings as well as the floor accelerations of the top story. This promising installation increases the significant capacity in the building at the expanse of significant displacements appearing in the tuned mass damper. The overturning of the tuned mass damper due to horizontal displacements accompanying with vertical excitation is identified for their stability. Alternative solutions to reduce the tuned mass damper displacements is to install an additional viscous damper. However, this may increase the drift ratio of the buildings. Therefore, this scheme is not proposed in this research. The fragility curves of the building are also developed to implement in the hazard planning.
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Yeh, Shih-Hao, and 葉士豪. "Analysis and Optimal Design of Beam with Tuned Mass Dampers." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/90963060573673000638.
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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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Pereira, João Tiago Ribeiro. "Analysis of Non-Linearities in the Performance of Tuned Mass Dampers." Master's thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/78402.
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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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Li, Jhih-Lun, and 李至侖. "Vibration Suppression of Building Installed with Simple Pendulum Tuned-Mass Dampers." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/77181747097850903103.
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碩士國立高雄應用科技大學
土木工程與防災科技研究所
98
Taiwan is located at the Pacific Seismic Ring so that earthquakes usually occur which induce a lot of disasters and collapse of buildings and thus how to increase the aseismic capacity of a building is important for structure engineers. In recent years various passive and active anti-earthquake technologies have been promoted but the cost of them are too high to be employed widely. This thesis is proposed to develop a newly vibration suppression system for buildings using simple pendulum type tuned mass dampers (SPTMD) and theoretically analyze the dynamic responses and oscillation suppression of buildings during various external dynamic loadings. Lumped mass models are employed to build up the dynamic models of building uninstalled and installed by different types (top level of single-storey, top level of two -storey, bottom level of two-storey, both level of two-storey etc.) and the dynamic equations are derived by both Newton’s and Lagrange’s equations and then expressed in state space form and finally the dynamic responses are computed by fourth-order Runge-Kutta algorithm. The effects of various parameters on vibration suppression for different dynamic excitations (such as free vibration, unit-step, harmonic loading, El Centro ground acceleration, etc.) are all studied in detail. Numerical results show that the SPTMD system can be employed to reduce the frequencies, increase the periods and suppress some dynamic responses of buildings. Among various installation types the ones installed at top level are the best and in such cases the suppression of accelerations is the most effective. Parameter study depict that all design factors including masses of the ball and bar of pendulum, damping coefficients, spring constants and length of pendulum are all important. The larger of the damping constants and the length of pendulum, the smaller of dynamic responses of building are obtained. WhileηBi=0.5, ηRi=0.005, ζRi=0.25, ζθi=0.25, li=2 and si/li=0.5 seems to be the better values for SPTMD installed on top level of single and two storey buildings. However, it is better when κRi&κθi are 0.5 and 0.25 for single and two story cases, respectively.
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Chang, Yi-Bin, and 張益賓. "Investigation on Optimal Parameters of Tuned Mass Dampers in Building Structures." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/86375218354728597317.
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碩士中原大學
土木工程研究所
102
Purpose of this paper is to explore the complex modal analysis tuned mass damper (TMD) of the optimal parameters, and with the vibration between the empirical formula of Den Hartog and genetic algorithms compare the three utility assessment. The structural system is developed by deriving the equations of motion for a building structure with a damper. Based on these governing equations, the optimal parameters of the damper are determined using the complex modal analysis in the frequency domain analysis. Under considerations of these optimal parameters, the time domain analysis is conducted to calculate the time histories of structural response for one types and three types of systems: without control, passive control and active control, i.e., fuzzy sliding mode control. The results indicate that the effectiveness of the complex modal analysis is relatively higher than that of the genetic algorithms in low damping building structure, whereas the effectiveness of the empirical formula of Den Hartog is comparatively insignificant; the effectiveness of the genetic algorithms is relatively higher than that of the empirical formula of Den Hartog in high damping building structure, whereas the effectiveness of the complex modal analysis is comparatively insignificant.
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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.
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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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Pereira, João Tiago Ribeiro. "Analysis of Non-Linearities in the Performance of Tuned Mass Dampers." Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/78402.
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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.
Full textAbstract:
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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Fang, Ge-Yang, and 方舸洋. "Optimal Design for Pounding Tuned Mass Dampers and the Performance under Excitation." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9e4kda.
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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.
Full textAbstract:
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.
Full textAbstract:
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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YILMAZ, ONUR CAN. "The Optimization of Offshore Wind Turbine Towers Using Passive Tuned Mass Dampers." 2014. https://scholarworks.umass.edu/masters_theses_2/54.
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Increasing energy demand and carbon emissions have driven the development of alternative energy solutions. One promising technology is wind energy. Wind energy technology developments has advanced substantially since the 1980s. Offshore wind turbines have become a major research focus, due to the promising offshore wind resource. However, challenges in offshore wind energy have arisen due to the additional wave loading and strong wind loads. Structural control systems have been implemented and researched in order to decrease dynamic response of these systems. The previous studies were successful at decreasing fatigue loads in the tower and support structure of offshore wind turbines. Giving these results, it is still unknown if the reduced loading enabled by structural control systems can allow for reduced material costs in the major structural components.
This research examines on an offshore wind turbine's tower-monopile structure by adding several configurations of passive tuned mass dampers, while simultaneously reducing the thickness of the structure in order to reduce costs. A range of candidate tower-monopile systems are created, and simulated in FAST-SC with and without passive tuned mass dampers. Fatigue and ultimate loads are calculated and analyzed. A variety of design criteria are considered including fatigue and ultimate loads, as well as local and global buckling. The results demonstrate that the tower-monopile thickness may be reduced up to 6.2% and still satisfy all design criteria.
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Yang, Chu-Hsien, and 楊楚賢. "Development of a System Framework for Optimal Design of Tuned Mass Dampers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/80465910944318123980.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
100
In recent years, tuned mass dampers have been widely used in structures to reduce the discomfort induced by vibration. However, the optimization of design variables for tuned mass dampers is very significant. There are some design formulas or closed form solutions for the structure without inherent damping, and simplified the structure as an one-degree-of freedom mass system. But in real structures, it is no possible for a structure without any damping and only one-degree-of freedom existed. Therefore, this thesis uses finite element package as the analysis engine to model and analyze the structure and then use the optimization tool to find the optimization variables in order to find a better solution to design tuned mass damper for any objective function. In this thesis, we derive the motion equation of the system with TMDs first, including different type of TMDs or system with different degree of freedom. While analyzing the response of system with TMD, transfer functions are always used. From transfer functions, we can understand the response of system in the frequency domain. Then we will introduce the design variables of TMD, for example, mass ratio, damping ratio, tuning frequency ratio and any variable needed like location of TMD. And introduce the objective function of TMD design problem. The root mean square of displacement or the peak value of response in frequency domain is often chosen. Then the system framework is developed in chapter 4. First of all, the optimal framework is verified by using a SDOF system without damping and validated the result of system with damping by iterative method and the proposed result in the reference paper. Secondly, make some discussion about series type tuned mass damper. Even if series type tuned mass damper is more effective than classic TMD, it will lose efficiency while the mistake in frequency ratio. So we adjust the form of objective function in order to improve the robustness of series type tuned mass damper. And then ,if we take force into account , we can get better result under the force we considered. Except SDOF system, MDOF systems like plate and beam are designed, too. At last, a ten-DOF system with a TMD or two TMDs is to make sure the feasibility of framework. According to the aforementioned, the framework constructed is performance well in TMD design problem.
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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.