• Title, Summary, Keyword: MR damper

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Optimal Design of MR Damper : Analytical Method and Finite Element Method (MR 댐퍼의 최적설계 : 이론적 방법 및 유한요소 방법)

  • Ha, Sung-Hoon;Seong, Min-Sang;Heung, Quoc-Nguyen;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.11
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    • pp.1110-1118
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    • 2009
  • This paper presents an optimal design of magnetorheological(MR) damper based on analytical methodology and finite element analysis. The proposed MR damper consists of MR valve and gas chamber. The MR valve is constrained in a specific volume and the optimization problem identifies geometric dimensions of the valve structure that maximize the pressure drop of the MR valve or damping force of the MR damper. In this work, the single-coil annular MR valve structure is considered. After describing the schematic configuration and operating principle of MR valve and damper, a quasi-static model is derived based on Bingham model of MR fluid. The magnetic circuit of the valve and damper is then analyzed by applying the Kirchoff' s law and magnetic flux conservation rule. Based on the quasi-static modeling and the magnetic circuit analysis, the optimization problem of the MR valve and damper is built. The optimal solution of the optimization problem of the MR valve structure constrained in a specific volume is then obtained and compared with the solution obtained from finite element method.

Cable vibration control with a semiactive MR damper-numerical simulation and experimental verification

  • Wu, W.J.;Cai, C.S.
    • Structural Engineering and Mechanics
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    • v.34 no.5
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    • pp.611-623
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    • 2010
  • Excessive stay cable vibrations can cause severe problems for cable-stayed bridges. In this paper a semiactive Magnetorheological (MR) damper is investigated to reduce cable vibrations. The control-oriented cable-damper model is first established; a computer simulation for the cable-damper system is carried out; and finally a MR damper is experimentally used to reduce the cable vibration in a laboratory environment using a semiactive control algorithm. Both the simulation and experimental results show that the semiactive MR damper achieves better control results than the corresponding passive damper.

Full-scale experimental verification on the vibration control of stay cable using optimally tuned MR damper

  • Huang, Hongwei;Liu, Jiangyun;Sun, Limin
    • Smart Structures and Systems
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    • v.16 no.6
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    • pp.1003-1021
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    • 2015
  • MR dampers have been proposed for the control of cable vibration of cable-stayed bridge in recent years due to their high performance and low energy consumption. However, the highly nonlinear feature of MR dampers makes them difficult to be designed with efficient semi-active control algorithms. Simulation study has previously been carried out on the cable-MR damper system using a semi-active control algorithm derived based on the universal design curve of dampers and a bilinear mechanical model of the MR damper. This paper aims to verify the effectiveness of the MR damper for mitigating cable vibration through a full-scale experimental test, using the same semi-active control strategy as in the simulation study. A long stay cable fabricated for a real bridge was set-up with the MR damper installed. The cable was excited under both free and forced vibrations. Different test scenarios were considered where the MR damper was tuned as passive damper with minimum or maximum input current, or the input current of the damper was changed according to the proposed semi-active control algorithm. The effectiveness of the MR damper for controlling the cable vibration was assessed through computing the damping ratio of the cable for free vibration and the root mean square value of acceleration of the cable for forced vibration.

Vibration mitigation of stay cable using optimally tuned MR damper

  • Huang, Hongwei;Sun, Limin;Jiang, Xiaolu
    • Smart Structures and Systems
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    • v.9 no.1
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    • pp.35-53
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    • 2012
  • Mechanical dampers have been proved to be one of the most effective countermeasures for vibration mitigation of stay cables in various cable-stayed bridges over the world. However, for long stay cables, as the installation height of the damper is restricted due to the aesthetic concern, using passive dampers alone may not satisfy the control requirement of the stay cables. In this connection, semi-active MR dampers have been proposed for the vibration mitigation of long stay cables. Although various studies have been carried out on the implementation of MR dampers on stay cables, the optimal damping performance of the cable-MR damper system has yet to be evaluated. Therefore, this paper aims to investigate the effectiveness of MR damper as a semi-active control device for the vibration mitigation of stay cable. The mathematical model of the MR damper will first be established through a performance test. Then, an efficient semi-active control strategy will be derived, where the damping of MR damper will be tuned according to the dynamic characteristics of stay cable, in order to achieve optimal damping of cable-damper system. Simulation study will be carried out to verify the proposed semi-active control algorithm for suppressing the cable vibrations induced by different loading patterns using optimally tuned MR damper. Finally, the effectiveness of MR damper in mitigating multi modes of cable vibration will be examined theoretically.

Damping updating of a building structure installed with an MR damper

  • Woo, Sung-Sik;Lee, Sang-Hyun
    • Smart Structures and Systems
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    • v.12 no.6
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    • pp.695-705
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    • 2013
  • The purpose of this paper is to identify through experiments the finite element (FE) model of a building structure using a magnetorheological (MR) fluid damper. The FE model based system identification (FEBSI) technique evaluates the control performance of an MR damper that has nonlinear characteristics as equivalent linear properties such as mass, stiffness, and damping. The Bingham and Bouc-Wen models were used for modeling the MR damper and the equivalent damping increased by the MR damper was predicted by applying an equivalent linearization technique. Experimental results indicate that the predicted equivalent damping matches well with the experimentally obtained damping.

Semi-Active Control of a Suspension System with a MR Damper of a Large-sized Bus (MR 댐퍼를 이용한 대형 버스 현가장치의 반능동 제어)

  • Yoon, Ho-Sang;Moon, Il-Dong;Kim, Jae-Won;Oh, Chae-Youn;Lee, Hyung-Won
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.21 no.4
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    • pp.683-690
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    • 2012
  • In this work, the semi-active control of a large-sized bus suspension system with an MR damper was studied. An MR damper model that can aptly describe the hysteretic characteristics of an MR damper was adopted. Parameter values of the MR damper model were suitably modified by considering the maximum damping force of a passive damper used in the suspension system of a real large-sized bus. In addition, a fuzzy logic controller was developed for semi-active control of a suspension system with an MR damper. The vertical acceleration at the attachment point of the MR damper and the relative velocity between sprung and unsprung masses were used as input variables, while voltage was used as the output variable. Straight-ahead driving simulations were performed on a road with a random road profile and on a flat road with a bump. In straight-ahead driving simulations, the vertical acceleration and pitch angle were measured to compare the riding performance of a suspension system with a passive damper with that of a suspension with an MR damper. In addition, a single lane change simulation was performed. In the simulation, the lateral acceleration and roll angle were measured in order to compare the handling performance of a suspension system using a passive damper with that of a suspension system using an MR damper.

Fuzzy Sky-hook Control of Semi-active Suspension System Using Rotary MR Damper (회전형 MR 댐퍼를 이용한 반능동 현가장치의 퍼지 스카이-훅 제어)

  • Cho, Jeong-Mok;Joh, Joong-Seon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.5
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    • pp.701-706
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    • 2007
  • Recently, a number of researches about linear magnetorheological(MR) damper using valve-mode characteristics of MR fluid have sufficiently undertaken, but researches about rotary MR damper using shear-mode characteristics of MR fluid are not enough. In this paper, we performed vibration control of shear-mode MR damper for unlimited rotating actuator of mobile robot. Also fuzzy logic based vibration control for shear-mode MR damper is suggested. The parameters, like scaling factor of input/output and center of the triangular membership functions associated with the different linguistic variables, are tuned by genetic algorithm. Simulation results demonstrate the effectiveness of the fuzzy-skyhook controller for vibration control of shear-mode MR damper under impact force.

Design and Performance Evaluation of MR Damper for the Reducing Vibration of a Flexible Pipe Conveying Fluid (유체유동에 의한 유연한 파이프의 진동 저감을 위한 파이프 지지용 MR댐퍼의 설계 및 성능 평가)

  • Park, Woo-Cheul;Lee, Hyun-Chang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.5
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    • pp.2100-2105
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    • 2013
  • This paper presents design and performance evaluation of MR damper for the reducing vibration of a flexible pipe conveying fluid. A novel type of MR damper which is suitable for pipe vibration characteristics is proposed and the MR damper is mathematically modeled and its damping force characteristics are evaluated. The vibration control performance of the MR damper associated with The cantilever pipe system is evaluated.

Design of Direct-Shear Mode MR Damper (전단 모드형 자성유체댐퍼의 설계)

  • Kim, Hae-Lan;Lee, Young-Shin;Lee, Eun-Yup;Lee, Gyu-Seop;Oh, Boo-Jin
    • Proceedings of the KSME Conference
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    • pp.626-631
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    • 2007
  • MR(Magneto-rheological) fluid is smart material that can be changed viscosity by controlling the magnetic field. MR damper with MR fluid can control damping force. It can be used extensively many engineering structures for reducing the effect of dynamic external disturbances. There are three kinds of MR dampers, such as valve mode, direct-shear mode and squeeze mode. In this study, design process of direct-shear mode MR damper with the MR fluid gap was developed. The parameters that used in the direct-shear mode MR damper Informed from the experiment of valve mode MR damper of Lord company. Magnetic analysis with finite element method was performed to find the optimal annular gap.

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Reliability assessment of semi-active control of structures with MR damper

  • Hadidi, Ali;Azar, Bahman Farahmand;Shirgir, Sina
    • Earthquakes and Structures
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    • v.17 no.2
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    • pp.131-141
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    • 2019
  • Structural control systems have uncertainties in their structural parameters and control devices which by using reliability analysis, uncertainty can be modeled. In this paper, reliability of controlled structures equipped with semi-active Magneto-Rheological (MR) dampers is investigated. For this purpose, at first, the effect of the structural parameters and damper parameters on the reliability of the seismic responses are evaluated. Then, the reliability of MR damper force is considered for expected levels of performance. For sensitivity analysis of the parameters exist in Bouc- Wen model for predicting the damper force, the importance vector is utilized. The improved first-order reliability method (FORM), is used to reliability analysis. As a case study, an 11-story shear building equipped with 3 MR dampers is selected and numerically obtained experimental data of a 1000 kN MR damper is assumed to study the reliability of the MR damper performance for expected levels. The results show that the standard deviation of random variables affects structural reliability as an uncertainty factor. Thus, the effect of uncertainty existed in the structural model parameters on the reliability of the structure is more than the uncertainty in the damper parameters. Also, the reliability analysis of the MR damper performance show that to achieve the highest levels of nominal capacity of the damper, the probability of failure is greatly increased. Furthermore, by using sensitivity analysis, the Bouc-Wen model parameters which have great importance in predicting damper force can be identified.