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Parveen P, Sadha, i Anila S. "Seismic Analysis of RCC Buildings Using Water Tanks as Tuned Liquid Mass Dampers". Journal of Recent Activities in Architectural Sciences 8, nr 1 (10.05.2023): 20–28. http://dx.doi.org/10.46610/joraas.2023.v08i01.003.
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A Tuned Mass Damper (TMD) is a device that is mounted to a structure to reduce the dynamic response of the structure. It is made up of a mass, a spring, and a damper. The damper's frequency is tuned to a specific structural frequency, and when that frequency is excited, it will resonate in an opposite direction to the structural motion. Tuned Liquid Mass Dampers are more recommended when compared to Tuned Mass Damper due to their respective advantages. The overhead water tanks can act as Tuned Liquid Mass Dampers. In this study, the overhead water tanks in RCC buildings are used to represent liquid-tuned mass dampers. The impact of Multiple Liquid Tuned Mass Dampers on the RCC buildings with and without tuned liquid mass dampers is to be studied. Utilizing response spectrum analysis, the study was conducted on buildings that have hexagonal and rectangular shapes. The trials are repeated by changing the water levels in tanks to empty, one-third level, two-thirds level and full water tank conditions. Comparisons of seismic parameters are done for demonstrating the functionality of a tuned liquid mass damper.
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Papalou, A., i S. F. Masri. "Performance of Particle Dampers Under Random Excitation". Journal of Vibration and Acoustics 118, nr 4 (1.10.1996): 614–21. http://dx.doi.org/10.1115/1.2888343.
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An experimental and analytical study is made of the performance of particle dampers under wide-band random excitation. A small model, provided with a nonlinear auxiliary mass damper, was used to investigate the major system parameters that influence the performance of particle dampers: total auxiliary mass ratio, particle size, container dimension, and the intensity and direction of the excitation. It is shown that properly designed particle dampers, even with a relatively small mass ratio, can considerably reduce the response of lightly damped structures. An approximate analytical solution, which is based on the concept of an equivalent single unit-impact damper, is presented. It is shown that the approximate solution can provide an adequate estimate of the root-mean-square response of the randomly excited primary system when provided with a particle damper that is operating in the vicinity of its optimum range of parameters.
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Yadav, Ajay, Devangkumar Talaviya, Ankit Bansal i Mohit Law. "Design of Chatter-Resistant Damped Boring Bars Using a Receptance Coupling Approach". Journal of Manufacturing and Materials Processing 4, nr 2 (3.06.2020): 53. http://dx.doi.org/10.3390/jmmp4020053.
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Deep hole boring using slender bars that have tuned mass dampers integrated within them make the boring process chatter vibration resistant. Dampers are usually designed using classical analytical solutions that presume the (un)damped boring bar which can be approximated by a single degree of freedom system, and the damper is placed at the free end. Since the free end is also the cutting end, analytical models may result in infeasible design solutions. To place optimally tuned dampers within boring bars, but away from the free end, this paper presents a receptance coupling approach in which the substructural receptances of the boring bar modelled as a cantilevered Euler–Bernoulli beam are combined with the substructural receptances of a damper modelled as a rigid mass integrated anywhere within the bar. The assembled and damped system response thus obtained is used to predict the chatter-free machining stability limit. Maximization of this limit is treated as the objective function to find the optimal mass, stiffness and damping of the absorber. Proposed solutions are first verified against other classical solutions for assumed placement of the absorber at the free end. Verified models then guide prototyping of a boring bar integrated with a damper placed away from its free end. Experiments demonstrate a ~100-fold improvement in chatter vibration free machining capability. The generalized methods presented herein can be easily extended to design and develop other damped and chatter-resistant tooling systems.
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Štěpánek, Jan, i Jiří Máca. "OPTIMIZATION OF TUNED MASS DAMPERS ATTACHED TO DAMPED STRUCTURES - MINIMIZATION OF MAXIMUM DISPLACEMENT AND ACCELERATION". Acta Polytechnica CTU Proceedings 30 (22.04.2021): 98–103. http://dx.doi.org/10.14311/app.2021.30.0098.
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A tuned mass damper is a device, which can be highly helpful while dealing with dynamic behaviour of structures. Its proper design is conditioned by knowledge of both loading and the structure properties. In many cases, the structure can be represented by single degree of freedom model, which simplifies the design and optimization of tuned mass dampers. Most of studies focus only on minimization of displacement of the main structure under harmonic force load, however, in many cases, different frequency response function would be more appropriate. This paper presents an extension of design formulas for the H∞ optimization of tuned mass dampers for damped structures and various frequency response functions.
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Wang, Min, Yan Lin Zhang i Tao Zan. "Performance Optimization and Comparison of TMD, MTMD and DTMD for Machining Chatter Control". Advanced Materials Research 199-200 (luty 2011): 1165–70. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.1165.
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This paper investigates and analyzes the performances of several types of tuned mass damper (TMD) including common single TMD(STMD), multiple tuned mass dampers (MTMD) and dual tuned mass dampers (DTMD) on the machining chatter control. Considering the special nature of the machining stability problem, the optimal design parameters of the dampers are defined as those that minimize the magnitude of the real part of the FRF of the damped machining system. This paper demonstrates the performance of the optimally designed different TMDs for machining stability improvement by calculating the stability diagrams for the turning processes. The calculation results show that a more than 60% improvement in the critical limiting cutting depth can be obtained for the optimally designed MTMD (2 TMDs) compared to the optimally designed STMD, and a more than20% improvement for the optimally designed DTMD compared to the optimally designed MTMD(2 TMDs).
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Rahman, Mohammad Sabbir, Md Kamrul Hassan, Seongkyu Chang i Dookie Kim. "Adaptive multiple tuned mass dampers based on modal parameters for earthquake response reduction in multi-story buildings". Advances in Structural Engineering 20, nr 9 (24.11.2016): 1375–89. http://dx.doi.org/10.1177/1369433216678863.
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The primary objective of this research is to find the effectiveness of an adaptive multiple tuned mass damper distributed along with the story height to control the seismic response of the structure. The seismic performance of a 10-story building was investigated, which proved the efficiency of the adaptive multiple tuned mass damper. Structures with single tuned mass damper and multiple tuned mass dampers were also modeled considering the location of the dampers at the top of the structure, whereas adaptive multiple tuned mass damper of the structure was modeled based on the story height. Selection of the location of the adaptive multiple tuned mass damper along with the story height was dominated by the modal parameters. Participation of modal mass directly controlled the number of the modes to be considered. To set the stage, a comparative study on the displacements and modal energies of the structures under the El-Centro, California, and North-Ridge earthquakes was conducted with and without various types of tuned mass dampers. The result shows a significant capability of the proposed adaptive multiple tuned mass damper as an alternative tool to reduce the earthquake responses of multi-story buildings.
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Inoue, Masanobu, Isao Yokomichi i Koju Hiraki. "Particle Damping with Granular Materials for Multi Degree of Freedom System". Shock and Vibration 18, nr 1-2 (2011): 245–56. http://dx.doi.org/10.1155/2011/309682.
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A particle damper consists of a bed of granular materials moving in cavities within a multi degree-of-freedom (MDOF) structure. This paper deals with the damping effects on forced vibrations of a MDOF structure provided with the vertical particle dampers. In the analysis, the particle bed is assumed to be a single mass, and the collisions between the granules and the cavities are completely inelastic, i.e., all energy dissipation mechanisms are wrapped into zero coefficient of restitution. To predict the particle damping effect, equations of motion are developed in terms of equivalent single degree-of-freedom (SDOF) system and damper mass with use made of modal approach. In this report, the periodic vibration model comprising sustained contact on or separation of the damper mass from vibrating structure is developed. A digital model is also formulated to simulate the damped motion of the physical system, taking account of all vibration modes. Numerical and experimental studies are made of the damping performance of plural dampers located at selected positions throughout a 3MDOF system. The experimental results confirm numerical prediction that collision between granules and structures is completely inelastic as the contributing mechanism of damping in the vertical vibration. It is found that particle dampers with properly selected mass ratios and clearances effectively suppress the resonance peaks over a wide frequency range.
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Ferreyra, María Victoria, Julián M. Gómez-Paccapelo, Ramiro Suarez i Luis A. Pugnaloni. "Avoiding chaos in granular dampers". EPJ Web of Conferences 249 (2021): 15003. http://dx.doi.org/10.1051/epjconf/202124915003.
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Granular dampers are passive devices used to attenuate mechanical vibrations. The most common configuration consists in an enclosure, partiallyfilled with particles, attached to the vibrating structure that needs to be damped. The energy is dissipated due to inelastic collisions and friction between the grains and between the grains and the inner walls of the container as the structure vibrates. As a result of the collisions, the mechanical response of the system often results in chaotic motion even if the driving is harmonic. Despite the vibration attenuation achieved, this chaotic response may render the granular damper unsuitable for a range of applications. In this work, we showcase two simple modifications of the enclosure design that are able to mitigate the chaotic response of the granular damper. To this end we use Discrete Element Method simulations of: (a) a granular damper with a conical base, and (b) a granular damper with obstaclesfixed inside the enclosure. We compare results against a standardflat-base enclosure damper. The basic mechanical response of the dampers is characterized by measuring the apparent mass and the loss factor. The suppression of the chaotic response is assessed qualitatively via the phase space diagram.
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Setareh, Mehdi. "Floor vibration control using semi-active tuned mass dampers". Canadian Journal of Civil Engineering 29, nr 1 (1.02.2002): 76–84. http://dx.doi.org/10.1139/l01-063.
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This paper discusses the application of a new class of semi-active tuned mass dampers, called ground-hook tuned mass dampers (GHTMD), for the reduction of floor vibrations due to human movements. The TMD introduced uses a continuously variable semi-active damper (ground-hook damper) to achieve reduction in the floor acceleration. Here, the GHTMD is applied to a single degree of freedom system representative of building floors. The GHTMD design parameters are defined in terms of non-dimensional values. The optimum values of these parameters are found based on the minimization of the acceleration response of the floor for different GHTMD mass ratios and floor damping ratios. The performance of the GHTMD is compared to that of the equivalent passive TMD. In addition, the effects of off-tuning due to variations in the mass ratios and frequency ratios of the TMD and GHTMD are studied. Comparison of the results demonstrates the efficiency and robustness of GHTMD with respect to equivalent TMD. Finally, a guide for the design of GHTMDs is presented.Key words: floor vibrations, semi-active tuned mass dampers, tuned vibration absorbers, vibration control, ground-hook dampers, human-induced vibrations, annoying vibrations, optimum design parameters.
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Khazaei, Mohsen, Reza Vahdani i Ali Kheyroddin. "Optimal Location of Multiple Tuned Mass Dampers in Regular and Irregular Tall Steel Buildings Plan". Shock and Vibration 2020 (16.09.2020): 1–20. http://dx.doi.org/10.1155/2020/9072637.
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Tuned mass dampers are one of the most common devices for the passive control of structures subjected to earthquakes. The structure of these dampers consists of three main parameters: mass, damping, and stiffness. Tuned mass dampers reduce the amplitude of the responses affecting on a mode. In most cases, only a single TMD (tuned mass damper) or a few dampers at several points above the building height are installed on the roof of the building, requiring considerable mass and space in some parts of the structure as overhead. It is also more important to predict the elements that will meet the required mass. In this research, the performance of multiple tuned mass dampers (MTMDs) is investigated in L- and U-shaped regular and irregular tall steel buildings with 10 and 20 floors, under the near- and far-field records. Nonlinear time history analysis is also applied to evaluate the multiple tuned mass dampers effects on the seismic responses of the structures. The SAP2000 API and MATLAB genetic algorithm are used to determine the optimal location of the MTMDs in the roof plans of the buildings. The results show the effects of multiple tuned mass dampers in reducing the seismic response of acceleration, displacement, and base shear up to 50, 40, and 40% in average, respectively. The results of determining the optimum location of MTMDs in the models indicate the importance of the symmetry of the dampers relative to the centre of mass of the building.
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Makino, Akifumi. "High-Rise Building Seismic Vibration Control Using Large Tuned Top-Floor Mass Damper". Journal of Disaster Research 4, nr 3 (1.06.2009): 246–52. http://dx.doi.org/10.20965/jdr.2009.p0246.
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This paper details the design of a high-rise reinforced concrete building whose top floor is isolated and used as the mass for a large-scale mass damper, describing the effect of the vibration control realized. Conventional mass dampers with additional weight at the building tops have been installed to improve environmental vibration against strong wind. Mass dampers have rarely been used, however, as measure against earthquakes. We developed large-scale vibration control using the top floor building weight to serve as a mass damper. The building is a high-rise reinforced concrete structure, 162 meters high, with 43 above-ground stories. Based on seismic response analysis using artificial earthquake waves, the natural vibration period of the mass damper was tuned to decrease story drift in the entire building. The mass damper reduced maximum story drift angle by 20%.
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Chesné, Simon. "Hybrid skyhook mass damper". Mechanics & Industry 22 (2021): 49. http://dx.doi.org/10.1051/meca/2021050.
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The objective of this study is to increase the efficiency of an initial passive Tuned Mass Damper (TMD) by adding an active control unit. A critical issue in many engineering domains is the design of fail-safe active systems. The proposed hybrid system aims to address this issue and realizes the said objective. It emulates the behavior of a skyhook damper parallel to a passive TMD. Skyhook dampers acts like viscous dampers connected to the ground, reducing the vibration amplitudes without any overshoot. It can be difficult to design a specific control law to obtain a desired dynamical behavior. The paper presents two ways to understand and design the hyperstable control law for Hybrid Mass Damper (HMD) (also called Active TMD), using the power flow formulation or the mechanical impedance analysis. These approaches are illustrated through the synthesis of this hybrid device and the emulation of the Skyhook damper. It is shown that a well-designed control law for this kind of system may result in high damping performance, ensuring stability and a fail-safe behavior. In addition, the amplitude of the primary system’s response is reduced over the entire frequency range which is not the case for the usual active or hybrid systems. Robustness is analyzed and compared to that of the classical active mass damper, and an experimental set up validates the proposed hybrid system.
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LI, CHUNXIANG. "PERFORMANCE OF DUAL-LAYER MULTIPLE TUNED MASS DAMPERS FOR STRUCTURES UNDER GROUND EXCITATIONS". International Journal of Structural Stability and Dynamics 06, nr 04 (grudzień 2006): 541–57. http://dx.doi.org/10.1142/s0219455406002106.
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The dual-layer multiple tuned mass dampers (DL-MTMD) with a uniform distribution of natural frequencies are proposed, which consist of one large tuned mass damper (L-TMD) and an arbitrary number of small tuned mass dampers (S-TMD). The structure is represented by a generalized system corresponding to the specific vibration mode to be controlled. The criterion for assessing the optimum parameters and effectiveness of the DL-MTMD is based on the minimization of the minimum values of the maximum dynamic magnification factors (DMF) of the structure installed with the DL-MTMD. Also considered is the stroke of the DL-MTMD. The proposed DL-MTMD system is demonstrated to show higher effectiveness and robustness to the change in frequency tuning, in comparison to the multiple tuned mass dampers (MTMD) with equal total mass ratios. It is also demonstrated to be more effective than the dual tuned mass dampers (DTMD) with one large and one small tuned mass damper, but they maintain the same level of robustness to the change in frequency tuning. The DL-MTMD system can be easily manufactured as the optimum value for the linking dashpots between the structure and L-TMD is shown to be zero.
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Ying Zhang, Sara, Yi-Yuan Li, Jason Zheng Jiang, Simon A. Neild i John H. G. Macdonald. "A methodology for identifying optimum vibration absorbers with a reaction mass". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, nr 2228 (sierpień 2019): 20190232. http://dx.doi.org/10.1098/rspa.2019.0232.
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Tuned mass dampers (TMDs), in which a reaction mass is attached to a structural system via a spring–parallel–damper connection, are commonly used in a wide range of applications to suppress deleterious vibrations. Recently, a mass-included absorber layout with an inerter element, termed the tuned mass damper inerter (TMDI), was introduced, showing significant performance benefits on vibration suppression. However, there are countless mass-included absorber layouts with springs, dampers and inerters, which could potentially provide more preferred dynamic properties. Currently, because there is no systematic methodology for accessing them, only an extremely limited number of mass-included absorber layouts have been investigated. This paper proposes an approach to identify optimum vibration absorbers with a reaction mass. Using this approach, a full class of absorber layouts with a reaction mass and a pre-determined number of inerters, dampers and springs connected in series and parallel, can be systematically investigated using generic Immittance-Function-Networks. The advan- tages of the proposed approach are demonstrated via a 3 d.f. structure example.
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Kwon, Oh Hoon, i Shin Hyoung Park. "Comparing the Effectiveness of Friction Damper and Tuned Mass Damper Using Numerical Simulation". Applied Mechanics and Materials 835 (maj 2016): 455–60. http://dx.doi.org/10.4028/www.scientific.net/amm.835.455.
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The purpose of this study is to evaluate and compare the effectiveness of friction dampers and tuned mass dampers (TMD) using numerical simulations. Wind and earthquake loads are simulated on a 15-story model building structure in which a friction damper and/or a TMD are installed. The idealized one-dimensional structure with a friction damper at each story and/or a TMD at the top of the building is subjected to a simulated load, and the displacement and acceleration responses of the structure are measured. The outcomes show that a TMD is more useful to control the vibration of the building from a wind load and a friction damper is more suitable for loads created by large accelerations such as those found during seismic events. This study provides verification on the performance of friction dampers and TMDs according to each of the two load types, wind and earthquake, through numerical simulations.
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Paul, P. Sam, Prashanth Raja, Philip Aruldhas, Sam Pringle i Elvin Shaji. "Effectiveness of particle and mass impact damping on tool vibration during hard turning process". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, nr 5 (27.07.2016): 776–86. http://dx.doi.org/10.1177/0954405416660995.
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In the machine tools, tool vibration is an undesirable phenomenon which affects tool life, quality of machined surface and produces irritating noise. This tool vibration is due to the interaction between metal cutting process and forces acting on the machine tool. In this investigation, an attempt was made to reduce tool vibration during turning of hardened steel using particle and mass impact dampers. A mass impact damper used in this investigation consists of a concentrated mass made of copper mounted on the bottom of the tool holder and particle damper consists of copper particles of 3.5 mm diameter positioned along the axis of the tool holder. Particle size and its location were designed using computational analysis and impact hammer–based modal testing was performed for both dampers. When these dampers were mounted on the tool holder, particles will collide with each other and subdue the vibration produced in the tool holder. Cutting experiments were conducted to study the influence of mass and particle damping on tool vibration and cutting performance during turning of hardened AISI4340 steel using hard metal insert with sculptured rake face. From the results, it was observed that the use of mass impact and particle dampers enhances the rigidity of the tool holder which, in turn, reduces tool vibration and improves the cutting performance. Among the two dampers, it was found that the presence of mass impact damping provides superior cutting performance when compared to particle damping.
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Tan, Aditya Suryadi, Thomas Sattel i Richard Subianto. "A Novel Design Concept of a Magnetorheological Fluid-Based Damper Utilizing the Porous Medium for Implementation in Small-Scale Applications". Fluids 8, nr 7 (7.07.2023): 203. http://dx.doi.org/10.3390/fluids8070203.
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Magnetorheological (MR) dampers have a virtue over conventional dampers, where their damping properties can be adjusted using a magnetic field. However, MR dampers have been barely implemented in small vibratory systems, in which the modal mass and stiffness are relatively small. This is due to two major reasons, namely its high parasitic damping force and big moving mass. When such an MR damper is installed in a small vibratory system, the system‘s default damping ratio is increased and therefore its dynamic is reduced. Here, a new concept of an MR damper utilizing the porous medium and shear operating mode together with an external non-moving electromagnet is proposed. This combination results in an MR damper with a low parasitic damping force and a small moving mass. For comparison purposes, a benchmark MR damper with comparable geometry is constructed. The proposed MR damper possesses a passive friction force that is 8× smaller and OFF-state passive viscous damping that is 10–20× smaller than the benchmark MR damper. An investigation of the proposed MR damper performance in a test vibratory system shows almost no reduction of the system dynamic. Therefore, this proposed MR damper configuration can be suitable for applications in small vibratory systems.
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Li, Peng, i Lei Zuo. "Influences of the electromagnetic regenerative dampers on the vehicle suspension performance". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, nr 3 (5.08.2016): 383–94. http://dx.doi.org/10.1177/0954407016639503.
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Conventional vehicle suspensions suppress vehicle vibrations by dissipating the vibration energy into unrecyclable heat with hydraulic dampers. This can be a considerable amount of energy which is worthy of attention for energy recovery. Electromagnetic regenerative dampers, or shock absorbers, are proposed to harvest this dissipated energy and to improve the fuel efficiency. The suspension dynamics with these regenerative dampers can be significantly different from the suspension dynamics with conventional dampers. First, different from conventional hydraulic dampers, the electromagnetic regenerative dampers have a significantly higher inertia, which is introduced by the electromagnetic generator. This has an important impact on the suspension dynamics. Second, the damping coefficient of electromagnetic dampers is related to the electric load connected to the output of the generator and can be controllable. Although various concepts have been proposed, the influences of these types of regenerative damper on the vehicle dynamics have not yet been thoroughly investigated. This paper models two types of rotational electromagnetic regenerative damper, with and without a mechanical motion rectifier, and analyzes their influences on the vehicle suspension performance in comparison with those of the conventional damper. The modeling in this paper also considers the case when the tires lose contact with the ground. Simulations were carried out with step road profile excitations and road profile excitations defined by the International Standardization Organization in order to evaluate the influences of the equivalent inertia mass and the equivalent damping coefficient. The results showed that, with an optimized equivalent inertia mass, both types of electromagnetic damper can achieve better ride comfort performances than a constant damper does. In addition, the mechanical motion rectifier mechanism can significantly improve the ride comfort and the road-handling performance of electromagnetic regenerative dampers by reducing the negative effect of the amplified generator inertia. In addition, the energy-harvesting potential of the presented dampers under road profile excitations defined by the International Standardization Organization was evaluated.
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Cetin, Huseyin, Ersin Aydin i Baki Ozturk. "Optimal damper allocation in shear buildings with tuned mass dampers and viscous dampers". International Journal of Earthquake and Impact Engineering 2, nr 2 (2017): 89. http://dx.doi.org/10.1504/ijeie.2017.089038.
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Ozturk, Baki, Huseyin Cetin i Ersin Aydin. "Optimal damper allocation in shear buildings with tuned mass dampers and viscous dampers". International Journal of Earthquake and Impact Engineering 2, nr 2 (2017): 89. http://dx.doi.org/10.1504/ijeie.2017.10010008.
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Satria, E., L. Son, M. Bur i M. Dzul Akbar. "Finite Element Analysis to Determine Stiffness, Strength, and Energy Dissipation of U-Shaped Steel Damper under Quasi-Static Loading". International Journal of Automotive and Mechanical Engineering 18, nr 3 (21.09.2021): 9042–50. http://dx.doi.org/10.15282/ijame.18.3.2021.16.0693.
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In seismic areas, the application of structural dampers becomes compulsory in the design of buildings. There are various types of dampers, such as viscous elastic dampers, viscous fluid dampers, friction dampers, tune mass dampers, yielding/ metallic dampers, and magnetic dampers. All damper systems are designed to protect structural integrities, control damages, prevent injuries by absorbing earthquake energy, and reduce deformation. This paper is a part of research investigating the behaviour of the U-shaped steel damper (as one type of metallic damper) that can be applied to the buildings in seismic areas. The dampers are used as connections between the roof and supporting structure, with the two general purposes. The first is to control the displacement of roof under an earthquake, and the second is to absorb seismic energy through the plasticity of some parts in dampers. If a strong earthquake occurs, the plasticity will absorb the seismic energy; therefore, heavy damage could be avoided from the roof’s mainframes. In this paper, several models of U-shaped steel dampers are introduced. Several parameters, such as elastic stiffness, maximum strength, and energy dissipation, are determined under two conditions. Firstly, static analysis of the proposed damper under variation of U-steel plate configurations, searching the model with more significant energy dissipation. Secondly, static analysis of the unsymmetrical and symmetrical damper under different loading directions. An in-house finite element program that involves both geometrical and material nonlinearities is developed as a problem solver. A quasi-static lateral loading is given to each model until one cycle of the hysteresis curve is reached (in the displacement range between -20 mm to +20 mm). The above parameters are calculated from the hysteresis curve. From the results, the behaviour of the U-steel damper can be described as follows. Firstly, increasing the energy dissipation in the lateral direction can be done by increasing the lateral stiffness of the damper. However, it can reduce the maximum elastic deformation of the damper. Secondly, under the random direction of loading, a symmetrical shape can increase the energy dissipation of the damper.
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Gutierrez Soto, Mariantonieta, i Hojjat Adeli. "Tuned Mass Dampers". Archives of Computational Methods in Engineering 20, nr 4 (19.10.2013): 419–31. http://dx.doi.org/10.1007/s11831-013-9091-7.
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Berger, E. J., i C. M. Krousgrill. "On Friction Damping Modeling Using Bilinear Hysteresis Elements". Journal of Vibration and Acoustics 124, nr 3 (12.06.2002): 367–75. http://dx.doi.org/10.1115/1.1473831.
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Massless bilinear hysteresis elements are often used to model frictional energy dissipation in dynamic systems. These quasi-static elements possess only two describing parameters, the damper stiffness and the force at which it slips. Bilinear hysteresis elements capture the qualitative nature of friction-damped forced response, but sometimes have difficulty with quantitative comparisons. This paper examines the performance of massless bilinear hysteresis elements as well as the role of damper mass in energy dissipation, and specifically evaluates its influence on the kinematic state of the damper (pure slip, stick-slip, pure stick). Differences between the massless and non-zero mass case are explored, as are the implications on both damper and system response. The results indicate that even small damper mass can have a qualitative effect on the system response, and provide advantages over the massless case. Further, we develop transition maps, describing damper response kinematics in the damper parameter space, which segment the space into two linear analysis regions (pure slip, pure stick) and one nonlinear analysis region (stick-slip). The results suggest non-zero mass dampers which are tuned as optimal vibration absorbers provide substantial resonance response attenuation and substantially reduce the size of the nonlinear analysis region in the damper parameter space.
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Chen, Jian Guo, Jun Sheng Cheng i Yong Hong Nie. "Research on the Decoupling Control Algorithm of Full Vehicle Semi-Active Suspension". Advanced Materials Research 479-481 (luty 2012): 1355–60. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1355.
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Vehicle suspension is a MIMO coupling nonlinear system; its vibration couples that of the tires. When magneto-rheological dampers are adopted to attenuate vibration of the sprung mass, the damping forces of the dampers need to be distributed. For the suspension without decoupling, the vibration attenuation is difficult to be controlled precisely. In order to attenuate the vibration of the vehicle effectively, a nonlinear full vehicle semi-active suspension model is proposed. Considering the realization of the control of magneto-rheological dampers, a hysteretic polynomial damper model is adopted. A differential geometry approach is used to decouple the nonlinear suspension system, so that the wheels and sprung mass become independent linear subsystems and independent to each other. A control rule of vibration attenuation is designed, by which the control current applied to the magneto-rheological damper is calculated, and used for the decoupled suspension system. The simulations show that the acceleration of the sprung mass is attenuated greatly, which indicates that the control algorithm is effective and the hysteretic polynomial damper model is practicable.
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Fu, Bo, Huanjun Jiang i Jin Chen. "Substructure Shake Table Testing of Frame Structure–Damper System Using Model-Based Integration Algorithms and Finite Element Method: Numerical Study". Symmetry 13, nr 9 (18.09.2021): 1739. http://dx.doi.org/10.3390/sym13091739.
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Substructure shake table testing (SSTT) is an advanced experimental technique that is suitable for investigating the vibration control of secondary structure-type dampers such as tuned mass dampers (TMDs). The primary structure and damper are considered as analytical and experimental substructures, respectively. The analytical substructures of existing SSTTs have mostly been simplified as SDOF structures or shear-type structures, which is not realistic. A common trend is to simulate the analytical substructure via the finite element (FE) method. In this study, the control effects of four dampers, i.e., TMD, tuned liquid damper (TLD), particle damper (PD) and particle-tuned mass damper (PTMD), on a frame were examined by conducting virtual SSTTs. The frame was modeled through stiffness-based beam-column elements with fiber sections and was solved by a family of model-based integration algorithms. The influences of the auxiliary mass ratio, integration parameters, time step, and time delay on SSTT were investigated. The results indicate that the TLD had the best performance. In addition, SSTT using model-based integration algorithms can provide satisfactory results, even when the time step is relatively large. The effects of integration parameters and time delay are not significant.
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Kim, Young Moon, Ki Pyo You, Jang Youl You, Sun Young Paek i Byung Hee Nam. "LQG Control of Along-Wind Responses of Tall Building Using Composite Tuned Mass Dampers". Key Engineering Materials 723 (grudzień 2016): 753–59. http://dx.doi.org/10.4028/www.scientific.net/kem.723.753.
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A composite tuned mass damper(CTMD) is a vibration control device consisting of an active-passive tuned mass dampers supported on the primary vibrating structure. The performance of CTMD in mitigating wind-induced vibration of tall building is investigated. Optimum parameters of a passive tuned mass damper(PTMD)for minimizing the variance response of the damped primary structure under random loads, with different mass ratio of an active tuned mass damper(ATMD) to a PTMD have been used for the optimum parameters of CTMD. The active control force generated by ATMD actuator was estimated by using linear quadratic Gaussian(LQG) controller, and the fluctuating along-wind load, treated as a stationary random process ,was simulated numerically using the along-wind load spectrum proposed by Solari .Comparing the along-wind rms response of tall building without a CTMD, the CTMD is effective in reducing the response to 40%~45% of the response without the CTMD. Therefore, the CTMD system was effective in reducing wind-induced vibration of tall building.
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Xu, Yichao, Changzhao Li, Yu Cheng i Yufeng Zhang. "Effectiveness of High-Damping Rubber (HDR) Damper and Tuned Mass—HDR Damper in Suppressing Stay-Cable Vibration". Applied Sciences 13, nr 5 (6.03.2023): 3356. http://dx.doi.org/10.3390/app13053356.
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High-damping rubber (HDR) dampers have the advantages of convenience for various shapes of pressure blocks, aesthetic installation, easy maintenance, temperature stability, etc.; thus, they present good application prospects in the vibration reduction of stay cables. Hence, a model of a taut cable equipped with two types of HDR damper—i.e., HDR damper and tuned mass–high-damping rubber damper (TM-HDR-D)—is established herein. Then, based on this theoretical model, the effect of each damper acting alone and in combination on the cable’s additional modal damping is studied. Finally, an actual cable of a cable-stayed bridge is used to study the effectiveness of two dampers for practical engineering. The results show that, when the TM-HDR-D has a small mass, the total additional modal damping of the cable approximates the superposition of the respective effects of the two dampers. The damping effect of HDR mainly depends on its stiffness and installation position; meanwhile, the damping contribution of TM-HDR-D is mainly related to its tuning frequency and installation position. In practical engineering, the smaller installation mass of TM-HDR-D can make up for the lack of damping enhancement of the cable-end HDR damper.
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Ahmad, Aabas. "Analysis of Load Reduction of Floating Wind Turbines Using Passive Tuned Mass Dampers". International Journal for Research in Applied Science and Engineering Technology 9, nr 9 (30.09.2021): 1340–45. http://dx.doi.org/10.22214/ijraset.2021.38179.
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Abstract: An efficient method for restraining the large vibration displacements and loads of offshore floating wind turbines under harsh marine environment is proposed by putting tuned mass dampers in the cabin. A dynamics model for a barge-type offshore floating wind turbine with a fore–aft tuned mass damper is established based on Lagrange’s equations; the nonlinear least squares Leven berg–Marquardt algorithm is employed to identify the parameters of the wind turbine; different parameter optimization methods are adopted to optimize tuned mass damper parameters by considering the standard deviation of the tower top longitudinal displacement as the objective function. Aiming at five typical combined wind and wave load cases under normal running state of the wind turbine, the dynamic responses of the wind turbine with/without tuned mass damper are simulated and the suppression effect of the tuned mass damper is investigated over the wide range of load cases. The results show that when the wind turbine vibrates in the state of damped free vibration, the standard deviation of the tower top longitudinal displacement is decreased approximately 60% in 100 s by the optimized tuned mass damper with the optimum tuned mass damper mass ratio 1.8%. The standard deviation suppression rates of the longitudinal displacements and loads in the tower and blades increase with the tuned mass damper mass ratio when the wind turbine vibrates under the combined wind and wave load cases. When the mass ratio changes from 0.5% to 2%, the maximum suppression rates vary from 20% to 50% correspondingly, which effectively reduce vibration responses of the offshore floating wind turbine. The results of this article preliminarily verify the feasibilities of using a tuned mass damper for restraining vibration of the barge-type offshore floating wind turbine
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Yakovkin, Vadim, Mikhail Nikhamkin i Nikolay Sazhenkov. "MATHEMATICAL SIMULATION OF THE DRY FRICTION DAMPER FOR THE GAS TURBINE ENGINE GEAR WHEEL. PART 1". Perm National Research Polytechnic University Aerospace Engineering Bulletin, nr 70 (2022): 140–49. http://dx.doi.org/10.15593/2224-9982/2022.70.13.
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One of the ways to increase the vibration strength gas turbine engine parts is the use of dry friction dampers. The efficiency of such dampers essentially depends on the selection of their mass-rigidity characteristics, pressing force, and other parameters. For the correct choice of these parameters at the design stage, it is necessary both to understand the laws of operation of dampers and to have an adequate mathematical model of the process of interaction between the engine part and the damper. The proposed mathematical model for calculating the efficiency of dry friction dampers is based on the linearization of the described Coulomb friction processes, which is completely true for cases where only the macroslip process is presented. However, real processes of dry friction are also accompanied by microslip processes too. To evaluate the influence of the presence of microslip processes on the damping efficiency, and, as a result, on the accu-racy of the created mathematical model, an experimental assessment of the indirect hysteresis loss loops of the “damper-detail” system was carried out on a model installation. It is concluded that the damper displacement level and the surface roughness are proportional. A possibility to apply linear-ised model to full-scale components was justified by calculations. This includes the possibility to consider the microslip effects simulations and identify ways of the damper adjustment so as to minimise the influence of this effect. The results of the study are taken into account for the damped gearwheel model adjustment.
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Waghmare, Manisha V., Suhasini N. Madhekar i Vasant A. Matsagar. "Influence of Nonlinear Fluid Viscous Dampers on Seismic Response of RC Elevated Storage Tanks". Civil Engineering Journal 6 (9.12.2020): 98–118. http://dx.doi.org/10.28991/cej-2020-sp(emce)-09.
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The numerical investigation on the seismic response of RC elevated liquid storage tanks installed with viscous dampers is presented. A discrete two-mass model for the liquid and multi-degree of freedom system for staging, installed with the dampers are developed for Reinforced Concrete (RC) elevated liquid storage tanks. The elevated tank is assessed for seismic response reduction when provided with Linear Viscous Damper (LVD) and Nonlinear Viscous Damper (NLVD), installed in the staging. The RC elevated liquid storage tanks are analyzed for two levels of liquid containment in the tank, 100% and 25% of the tank capacity. Three Configurations of placements of dampers viz. dampers at alternate levels (Configuration I and Configuration II) and dampers at all the panels of the staging of the tank (Configuration III) are considered. To study the effect of peak ground acceleration, eight real earthquake time histories with accelerations varying from 0.1 g to 0.93 g are considered. The nonlinearity in the viscous damper is modified by taking force proportional to various velocity exponents. It is found that the nonlinear viscous dampers with lower damping constant result in a comparable reduction in the response of RC elevated liquid storage tank, to that of linear viscous dampers with higher damping constant. A lower damping constant signifies compact the size of the damper. Doi: 10.28991/cej-2020-SP(EMCE)-09 Full Text: PDF
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Chawhan, Rechal L., Nikhil H. Pitale, S. S. Solanke i Mangesh Saiwala. "Use of Tuned Liquid Damper to Control Structural Vibration Structural." IOP Conference Series: Materials Science and Engineering 1197, nr 1 (1.11.2021): 012053. http://dx.doi.org/10.1088/1757-899x/1197/1/012053.
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Abstract The aim of this paper is to study the tuned liquid damper and it’s effectivness. The tunned liquid dampers are simply tuned mass damper where the liquid (usually water) replaces the mass.Tuned liquid dampers is a water tank placed over the structure which is able to reduce the dynamic structural response subjected to stimulation through sloshing effect. The effectiveness of tuned liquid damper depends upon various parameters. Tuned liquid damper are suitable for high rise building rather than short building. The tuned liquid damper decreases effect of harmonic excitation by Dissipating the energy of excitation through sloshing phenomenon.
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Papaloun, Angeliki, i Elias Strepelias. "Structural Control of Monuments’ Response under Sinusoidal Excitation Using Particle Dampers". Open Construction and Building Technology Journal 8, nr 1 (31.12.2014): 351–56. http://dx.doi.org/10.2174/1874836801408010351.
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The effects of particle dampers attached on a classical column under dynamical loadings are investigated. A number of tests were performed to evaluate the ability of particle dampers to control the vibration of a small scale multidrum column under a swept-frequency sinusoidal signal. The particle damper can reduce considerably the response of the column to sinusoidal excitation when the size of the container, the mass ratio, the particle size and the placement of the damper are properly selected.
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Wang, Zhihao, Hui Gao, Hao Wang i Zhengqing Chen. "Development of stiffness-adjustable tuned mass dampers for frequency retuning". Advances in Structural Engineering 22, nr 2 (28.08.2018): 473–85. http://dx.doi.org/10.1177/1369433218791356.
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Tuned mass damper is an attractive strategy to mitigate the vibration of civil engineering structures. However, the performance of a tuned mass damper may show a significant loss due to the frequency detuning effect. Hence, an inerter-induced negative stiffness (apparent mass effect) and magnetic-force-induced positive/negative stiffness are proposed to integrate a stiffness-adjustable vertical tuned mass damper and pendulum tuned mass damper for frequency retuning, respectively. Based on the established differential equations of motion for a vertical tuned mass damper coupled with an inerter and a pendulum tuned mass damper integrated with a magnetic-force-induced positive-/negative-stiffness device, the frequency retuning principles of a vertical tuned mass damper and a pendulum tuned mass damper are, respectively, demonstrated. The frequency retuning strategies for both the vertical tuned mass damper and the pendulum tuned mass damper are confirmed and clarified by model tests. Furthermore, the performance of a retuned vertical tuned mass damper for mitigating vibration of a linear undamped single-degree-of-freedom primary structure is discussed, and the effects of the amplitudes of the pendulum tuned mass damper on magnetic-force-induced stiffness as well as the frequency of the pendulum tuned mass damper are also investigated. Both theoretical analysis and experimental investigations show that the proposed frequency tuning methodologies of tuned mass dampers are efficient and cost-effective with relatively simple configurations.
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Zhang, Zhi Qiang, i Fei Ma. "Research on Seismic Response Vibration Hybrid Control of Hefei TV Tower". Advanced Materials Research 243-249 (maj 2011): 5197–203. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5197.
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In this paper, Hefei TV Tower is used as an analytical case to examine the Hybrid control method on seismic response. Firstly, on the basis of the other’s work, a bi-model dynamic model is proposed to study the seismic response vibration hybrid control, using tuned mass damper and viscous fluid dampers. Then the optimal coefficient is obtained by considered the seismic response of upper turret as optimization objectives. According to analysis, it’s showed that the seismic responses of the tower are decreased greatly with tuned mass damper and viscous fluid dampers, and the vibration reduction effectiveness of the tower is sensitive to the spectral characteristics of earthquake wave.
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Mrad, Charbel, Magdalini D. Titirla i Walid Larbi. "Comparison of Strengthening Solutions with Optimized Passive Energy Dissipation Systems in Symmetric Buildings". Applied Sciences 11, nr 21 (28.10.2021): 10103. http://dx.doi.org/10.3390/app112110103.
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The aim of this study is to compare the seismic response of reinforced concrete (RC) symmetric buildings, with a varied number of stories, strengthening with three types of passive energy dissipation systems, as tuned mass dampers, viscous dampers, and friction dampers. The paper presents an overview of design optimization with the object of minimizing certain functions: (i) the maximum displacement at the top of the structures, (ii) the base shear loads, and (iii) the maximum interstory drift. The objective functions were evaluated in three residents’ buildings (a four-story building, a nine-story building, and a sixteen-story building) subjected to seven (real and artificial) seismic recorded accelerograms. For this purpose, 94 nonlinear dynamic analyses were carried out. The effects of each strengthening solution are presented, and from this innovative comparison (optimal design, three different passive energy systems, three different story numbers), further useful results were observed. The outcomes of the study show the effectiveness of a tuned mass damper (TMD) system, and how it might be better for tall and flexible structures than for stiffer structures. However, the response of the pendulum tuned mass damper (TMD) configuration is better than the conventional one because it acts in all directions. The viscous dampers (VDs) provide a significant reduction for mid-rise buildings, while friction dampers (FDs) boost the performance of all structures under seismic action, especially in terms of displacement, and they are more suitable for low-rise buildings.
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Kopylov, Semen, Zhaobo Chen i Mohamed AA Abdelkareem. "Back-iron design-based electromagnetic regenerative tuned mass damper". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 234, nr 3 (14.06.2020): 607–22. http://dx.doi.org/10.1177/1464419320932350.
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Implementation of tuned mass dampers is the commonly used approach to avoid excessive vibrations in civil engineering. However, due to the absence of the compact dimension, there are still no practical applications of the tuned mass dampers in automotive industry. Meanwhile, recent investigations showed the benefit of utilizing a tuned mass damper in a vehicle suspension in terms of driving comfort and road holding. Thus, the current investigation aimed to explore a novel compact dimension tuned mass damper, which can provide both sufficient vibration mitigation and energy harvesting. This paper presents a prototype of a back-iron-based design of an electromagnetic regenerative tuned mass damper. The mathematical model of the tuned mass damper system was developed and has been validated by the experimental results of the tuned mass damper prototype implemented in a protected mass test-bench. The indicated results concluded that the attenuation performance dramatically deteriorated under random excitations and a reduction in the root-mean-square acceleration of 18% is concluded compared to the case with undamped tuned mass damper. Under harmonic excitations, the designed tuned mass damper prototype is able to reduce the peak acceleration value of the protected structure by 79%. According to the experimental results, the designed tuned mass damper prototype revealed a peak regenerative power of 0.76 W under a harmonic excitation of 8.1 Hz frequency [Formula: see text]m amplitude. Given the simulated random road profiles from C to E, the back-iron electromagnetic tuned mass damper indicated that root-mean-square harvested power from 0.6 to 6.4 W, respectively.
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Murakami, Katsuhide, Masato Ishii, Kentaroh Miyazaki i Yasuhiro Tsuneki. "Proposal for an Efficient Damping System for High-Rise Buildings in Major Earthquakes". Journal of Disaster Research 11, nr 1 (1.02.2016): 106–17. http://dx.doi.org/10.20965/jdr.2016.p0106.
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Recent vibration resistant designs for buildings in Japan often adopt a vibration control structure with dampers arranged in the framework. Generally, the dampers are arranged in the building’s core in a geometry that works most effectively to protect against story shearing deformation. It is already known, however, that the above-mentioned arrangement of dampers does not provide good damping effects for the upper stories of high-rise buildings with large aspect ratios, because the protection mechanism is designed to decrease the shearing deformation components of the building’s horizontal deformation caused by its horizontal loads. A new type of dampers, called force-restricted tuned viscous mass dampers (FRTVMD), has been recently developed for such circumstances, amplifying the deformation of viscous dampers with their tuned mass effects. This paper, therefore, first presents a tuned mass damper (TMD) system, effective for high-rise buildings with large aspect ratios against great earthquakes, and then proposes a new vibration control structural system capable of generating better damping effects with FRTVMD. In addition, we review its characteristics and effects by analyzing its vibration response, as well as verify that a combined use of such vibration control structural systems will generate far greater damping effects than an individual system.
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Ahmad, Afham Zulhusmi, Aminudin Abu, Lee Kee Quen, Nor’azizi Othman i Faridah Che In. "EXPERIMENTAL ANALYSIS OF THE VISCOUS TUNED MASS DAMPER FOR THE ATTENUATION OF STRUCTURAL RESPONSES". Jurnal Teknologi 83, nr 6 (27.09.2021): 125–39. http://dx.doi.org/10.11113/jurnalteknologi.v83.17151.
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This paper presents a systematic experimental investigation on the performance of a Multiple Tuned Mass Dampers (MTMDs) attached to a structural system under dynamic load excitation. A Modal Experimental Analysis (EMA) of a three-story structural frame equipped with a viscous damper system was carried out through a series of shaking table tests to evaluate the performance and verify the analysis approach. Each of the TMDs consists of a mass attached to a structural floor via Thermoplastic Polyurethane (TPU) viscous bearing. Initially, the TMD was designed solely to control single mode vibration and then the mechanism is extended for the application of controlling multimode responses. The experiment demonstrated that the proposed viscous dampers exhibit good performance in reducing the response of structures under dynamic loads, and able to control both fundamental and higher vibration modes of a Multiple Degree of Freedom (MDOF) primary system effectively. It was also evident that the attachment of the air dashpot dampers to each of TMDs lead to better efficiency on controlling the amplification of the damper mass and significantly contribute to better structural modal tuning.
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Sikora, Marian. "Modeling and Operational Analysis of an Automotive Shock Absorber with a Tuned Mass Damper". Acta Mechanica et Automatica 12, nr 3 (1.09.2018): 243–51. http://dx.doi.org/10.2478/ama-2018-0038.
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Abstract Recently, the topic of energy dissipation efficiency of vehicle suspension dampers has become a research and engineering problem due to structural requirements of vehicle manufacturers and the introduction of electric/hybrid cars. By principle, any disturbances in the damping force generation process translate into pressure fluctuations to be then transferred to the body of the vehicle. The effect known as rattling within the damper engineering community is perceived as detrimental to ride comfort. To improve the performance of a vehicle damper several methods can be devised and used. One approach is to optimize the settings of the valves in the damper. The approach, however, often influences the force output of the damper. Another technique involves the application of add-on systems. One such system is the tuned mass damper concept originally developed by Frahm for structural engineering applications. In the paper the author proposes a damper concept equipped with an external/internal tuned mass damper component for improving the dynamic characteristics of vehicle dampers. The author presents modeling details followed by simulations of the damper with the tuned mass damper concept subjected to oscillatory inputs, and a critical analysis of the presented results.
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Zamora-Garcia, Diego A., Alejandro C. Ramirez-Reivich i Ma Pilar Corona-Lira. "Impact of Tuned Mass Dampers and Electromagnetic Tuned Mass Dampers on Geometrically Nonlinear Vibrations Reduction of Planar Cable Robots". Shock and Vibration 2023 (23.03.2023): 1–17. http://dx.doi.org/10.1155/2023/6951186.
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Vibration is one of the problems that limits the applications of cable driven parallel robots (CDPR). The problem is bigger in CDPR with planar configuration due to the presence of out-of-plane vibrations, which have a larger amplitude and settling time. Some authors have proposed solutions such as the increase in tension of the wires, increase in the end effector mass, or the use of active dampers. In this research, we investigated the performance of tuned mass dampers (TMD) and electromagnetic tuned mass dampers (ETMD) which are integrated in the end effector of a CDPR in a planar configuration with eight wires. The essential idea is to reduce the settling time of the end effector through free vibrations without the use of external energy. This research followed an analytical and experimental methodology with the following steps. Three mathematical models were formulated and analysed using numerical simulations. Then, a test bench to validate the analytical results was designed and built. The effectiveness of the dampers was evaluated by comparing the settling times of the following three cases: without damper, with TMD, and with ETMD. During the investigation, it was observed that the use of AMS can reduce the settling time using the appropriate parameters. The effectiveness of AEMS is highly dependent on frictions and can be effective in some scenarios. Reductions in settling time from marginal values to 95% can be obtained. This research implies a viable solution for the out-of-plane vibrations of planar CDPR.
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Cong, Cong. "Using active tuned mass dampers with constrained stroke to simultaneously control vibrations in wind turbine blades and tower". Advances in Structural Engineering 22, nr 7 (21.12.2018): 1544–53. http://dx.doi.org/10.1177/1369433218817892.
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Simultaneous control of wind turbine blades and tower vibrations is studied in this article. Four active tuned mass dampers have been incorporated into each blade and tower to reduce vibrations. A decentralized constrained H∞ velocity output feedback which restricts the tuned mass damper stroke as a hard constraint is proposed by solving linear matrix inequality. Each active tuned mass damper is driven individually by the output of the corresponding velocity signal. Considering the structural dynamics subjected to gravity, variable rotor speed, and aerodynamic loadings, a model describing dynamics of rotating blades coupled with tower, including the dynamics of active tuned mass dampers, was developed by Euler–Lagrangian formulation. A numerical simulation is carried out to verify the effectiveness of the proposed decentralized control scheme. Investigations show promising results for the active tuned mass damper in simultaneous control blade vibrations and tower vibrations by decentralized control approach. Numerical results demonstrate that the decentralized control has the similar performance compared to centralized control and effectively reduce the displacement of vibrations.
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Tophøj, Laust, Nikolaj Grathwol i Svend Hansen. "Effective Mass of Tuned Mass Dampers". Vibration 1, nr 1 (15.09.2018): 192–206. http://dx.doi.org/10.3390/vibration1010014.
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Tuned Mass Dampers (TMDs) are widely used for the control and mitigation of vibrations in engineering structures, including buildings, towers, bridges and wind turbines. The traditional representation of a TMD is a point mass connected to the structure by a spring and a dashpot. However, many TMDs differ from this model by having multiple mass components with motions of different magnitudes and directions. We say that such TMDs have added mass. Added mass is rarely introduced intentionally, but often arises as a by-product of the TMD suspension system or the damping mechanism. Examples include tuned pendulum dampers, tuned liquid dampers and other composite mechanical systems. In this paper, we show how a TMD with added mass can be analyzed using traditional methods for simple TMDs by introducing equivalent simple TMD parameters, including the effective TMD mass, the mass of the equivalent simple TMD. The presence of added mass always reduces the effective TMD mass. This effect is explained as a consequence of smaller internal motions of the TMD due to the increased inertia associated with the added mass. The effective TMD mass must be correctly calculated in order to predict the TMD efficiency and in order to properly tune the TMD. The developed framework is easy to apply to any given general linear TMD system with a known motion. Here, we demonstrate the approach for a number of well-known examples, including tuned liquid dampers, which are shown to use only a small fraction of the total liquid mass effectively.
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Horr, A. M., i L. C. Schmidt. "Frequency Domain Dynamic Analysis of Large Space Structures with Added Elastomeric Dampers". International Journal of Space Structures 11, nr 3 (wrzesień 1996): 279–89. http://dx.doi.org/10.1177/026635119601100301.
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Modern computer-based computational techniques such as the finite element method enable the structural dynamicist to make precise calculations of the mass and stiffness properties of complex large space structures (LSS). To obtain dissipation analysis up to the same level of sophisitcation as mass and stiffness analysis in damped structures, an equally accurate methodology is required. This paper presents one such methodology for LSS with added elastomeric dampers. Elastomeric dampers have been used in the different parts of LSS to absorb part of the vibrational energy, and to help reduce the damage caused by the dynamic forces. The purpose of this paper is to present the specturally formulated finite element analyses for damped LSS. Using the fractional derivative model, the non-linear damping characteristics of elastomeric dampers have been modelled.
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BAKRE, S. V., i R. S. JANGID. "OPTIMUM MULTIPLE TUNED MASS DAMPERS FOR BASE-EXCITED DAMPED MAIN SYSTEM". International Journal of Structural Stability and Dynamics 04, nr 04 (grudzień 2004): 527–42. http://dx.doi.org/10.1142/s0219455404001367.
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The optimum parameters of multiple tuned mass dampers (MTMD) for suppressing the dynamic response of a base-excited damped main system are investigated by a numerical searching technique. The criterion selected for the optimality is the minimization of the steady state displacement of the main system under harmonic base acceleration. The parameters of the MTMD that are optimized include: the damping ratio, the tuning frequency ratio and the frequency bandwidth. The optimum parameters of the MTMD system and corresponding displacement are obtained for different damping ratios of the main system and different mass ratios of the MTMD system. The explicit formulas for the optimum parameters of the MTMD (i.e. damping ratio, bandwidth and tuning frequency) are then derived using a curve-fitting scheme that can readily be used in engineering applications. The error in the proposed explicit expressions is investigated and found to be negligible. The effectiveness of the optimally designed MTMD system is also compared with that of the optimum single tuned mass damper. It is observed that the optimally designed MTMD system is more effective for vibration control than the single tuned mass damper. Further, the damping in the main system significantly influences the optimum parameters and the effectiveness of the MTMD system.
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Nguyen, QH, SB Choi i JK Woo. "Optimal design of magnetorheological fluid-based dampers for front-loaded washing machines". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, nr 2 (9.04.2013): 294–306. http://dx.doi.org/10.1177/0954406213485908.
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In this research, a magnetorheological fluid-based damper to attenuate vibration due to unbalanced laundry mass from a front-loaded washing machine is proposed and optimally designed with experimental validation. First, rigid vibration mode of the washing machine due to an unbalanced mass is analyzed, and an optimal positioning of the suppression system for the washing machine is figured out. In order to attenuate vibration from the washing machine, several configurations of magnetorheological damper are proposed considering available space and the required damping force of the system. Based on the Bingham rheological model of magnetorheological fluid, damping force of the proposed magnetorheological dampers is then derived. An optimal design problem for the proposed magnetorheological damper is constructed considering its zero-field friction force and the maximum damping force. The optimization objective is to minimize the zero-field friction force of the magnetorheological damper while the maximum value of damping force is kept being greater than a required value. An optimization procedure based on finite element analysis integrated with an optimization tool is employed to obtain optimal geometric dimensions of the magnetorheological dampers featuring different types of magnetorheological fluid. Optimal solutions of the magnetorheological dampers are then presented and the optimized damper is figured out. In addition, performance characteristics of the optimized magnetorheological damper are presented and discussed.
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Yang, Jian Wei, Ping Chen, Yu Zhang, Zhu Ma Yu i Xin Long Liu. "Study of Breeze Vibration of Overhead Transmission Lines with Dampers Using FEM Analysis". Advanced Materials Research 940 (czerwiec 2014): 65–68. http://dx.doi.org/10.4028/www.scientific.net/amr.940.65.
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The vertical, steady-state breeze vibration of transmission line with dampers attached are studied using FEM analysis. The lines are simulated by cable element, the dampers by mass element and beam element. The parameters of FEM emulation mode such as breeze vibration force, the conductor self-damping and dampers damping are emphasized by the energy equivalent theory. The breeze vibration force induced by vortex is educed by wind power curve, the hysteresis damping and friction damping of conductor and damper are translated into viscous damping. Results of the FEM emulation show the calculation accuracy of natural frequency of dampers, and prove that it can effectively restrain breeze vibration of transmission lines by installing dampers. The method lays foundation for further research on protecting breeze vibration of transmission lines.
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Lu, Zheng. "Parametric Studies of the Vibration Control Effects of a Nonlinear Damper System under Multi-Axis Excitations". Advanced Materials Research 712-715 (czerwiec 2013): 1682–85. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.1682.
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This paper studies the influence of system parameters to the vibration control effects of a nonlinear damper system under multi-axis excitations. The nonlinear damper system is composed of a particle damper and a primary structure. Based on numerical simulations, it is shown that: increasing the mass ratio can improve the dampers effectiveness, but only up to a certain level; applying particles with a high value of the coefficient of restitution can result in a broader range of acceptable response levels; a lightly-damped primary system can achieve a considerable reduction in its response with a small weight penalty; and that a cylindrically-shaped container provides a higher level of effectiveness than a rectangularly-shaped one.
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Di, Fangdian, Lin Chen i Limin Sun. "Optimal Design of Dampers for Multi-Mode Cable Vibration Control Based on Genetic Algorithm". International Journal of Structural Stability and Dynamics 21, nr 04 (19.02.2021): 2150058. http://dx.doi.org/10.1142/s0219455421500589.
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Cables in cable-stayed bridges are subjected to the problem of multi-mode vibrations. Particularly, the first ten modes of long cables can have a frequency less than 3[Formula: see text]Hz and hence are vulnerable to wind-rain induced vibrations. In practice, mechanical dampers are widely used to mitigate such cable vibrations and thus they have to be designed to provide sufficient damping for all the concerned vibration modes. Meanwhile, the behaviors of practical dampers are complicated and better to be described by mechanical models with many parameters. Furthermore, additional mechanical components such as inerters and negative stiffness devices have been proposed to enhance the damper performance on cables. Therefore, it is increasingly difficult to optimize the damper parameters for suppressing multi-mode cable vibrations. To address this issue, this study proposes a novel damper design method based on the genetic algorithm (GA). The procedure of the method is first introduced where the damper performance optimization is formulated as a single-objective multi-parameter optimization problem. The effectiveness of the method is then verified by considering a viscous damper on a stay cable. Subsequently, the method is applied to optimize three typical dampers for cable vibration control, i.e. the positive stiffness damper, the negative stiffness damper, and the viscous inertial mass damper. The results show that the GA-based method is effective and efficient for cable damper design to achieve best multi-mode control effect and it is particularly useful for dampers with more parameters.
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Yakovkin, Vadim, Aleksandr Pishchalnikov, Ilya Sokolov, Mikhail Nikhamkin i Nikolay Sazhenkov. "MATHEMATICAL SIMULATION OF THE DRY FRICTION DAMPER FOR THE GAS TURBINE ENGINE GEAR WHEEL. PART 2". Perm National Research Polytechnic University Aerospace Engineering Bulletin, nr 70 (2022): 150–59. http://dx.doi.org/10.15593/2224-9982/2022.70.14.
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There are some methods to improve vibration strength of the gas turbine engine bevel gearwheels by using the dry friction dampers capable of damping resonance vibrations and operate under extreme conditions. The effectiveness of these dampers depends significantly on an adjustment of their mass-stiffness properties, pressure and other parameters. It is required to under-stand the damper operation laws to make a right choice of the parameters during designing, and that could be addressed by test simulations. This paper provides an acceptability assessment of a mathematical model based on the Coulomb friction linearisation in a damper-to-gearwheel contact within the gas turbine engine. Bevel gearwheels have a complex dimensional mode configuration in the damper contact area, therefore a calculation analysis of dynamic behavior of the linearised gearwheel-damper system was carried out from the nominal contact parameters, such as contact fit, stiffness of the normal elastic members in the contact. It is concluded that the damper slipping and the surface roughness are proportional. The stable solution limits have been defined to minimise the unknown parameters effect on the calculation result when adjusting the damper. The research results are used when adjusting the damper for the aircraft engine gearwheel. The strain-gauging test data were compared to the calculation results for the engine damped gearwheel, an acceptable convergence on damping has been obtained.
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Ahmad, Aabas. "Load Reduction of Floating Wind Turbines Using Tuned Mass Dampers". International Journal for Research in Applied Science and Engineering Technology 9, nr 9 (30.09.2021): 1298–303. http://dx.doi.org/10.22214/ijraset.2021.38178.
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Abstract: 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 highquality winds over deep water, floating platforms for offshore wind turbines have been developed, but they suffer from greatly increased loading. One method to reduce loadsin offshore wind turbines is the application of structural control techniques usuallyused 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 byquantifying 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