• Title, Summary, Keyword: Damper

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Performance Test and Numerical Model Development of Restoring Viscous Damper for X-type Damper System (X형 감쇠시스템을 위한 복원성 점성 감쇠기 성능 실험 및 수치모형 개발)

  • Kim, David;Park, Jangho;Ok, Seung-Yong;Park, Wonsuk
    • Journal of the Korean Society of Safety
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    • v.31 no.6
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    • pp.52-57
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    • 2016
  • In this study, a restoring viscous damper is introduced for X-type damper system which is designed for the seismic response control of large spatial structures. A nonlinear numerical model for its behavior is developed using the result of dynamic loading tests. The X-type damper system is composed of restoring viscous dampers and connecting devices such as adjustable wire bracing, where the damping capacity of the system is controllable by changing the number of the dampers. The restoring viscous damper is devised to exert main damping force in tension direction, which is effective to prevent the buckling of bracing subjected to compressive axial force. To evaluate the performance of the proposed damper, dynamic cyclic loading tests are performed by using manufactured dampers at full scale. In order to construct the numerical model of the damper system, its model parameters are first identified using a nonlinear curve fitting method with the test data. The numerical simulations are then performed to validate the accuracy of the numerical model in comparison with the experimental test results. It is expected that the proposed system is effectively applicable to various building structures for seismic performance enhancement.

Control of a building complex with Magneto-Rheological Dampers and Tuned Mass Damper

  • Amini, F.;Doroudi, R.
    • Structural Engineering and Mechanics
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    • v.36 no.2
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    • pp.181-195
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    • 2010
  • Coupled building control is a viable method to protect tall buildings from seismic excitation. In this study, the semi-active control of a building complex is investigated for mitigating seismic responses. The building complex is formed of one main building and one podium structure connected through Magneto-Rheological (MR) Dampers and Tuned Mass Damper. The conventional semi-active control techniques require a primary controller as a reference to determine the desired control force, and modulate the input voltage of the MR damper by comparing the desired control force. The fuzzy logic directly determines the input voltage of an MR damper from the response of the MR damper. The control performance of the proposed fuzzy control technique for the MR damper is evaluated for the control problem of a seismically-excited building complex. In this paper, a building complex that include a 14-story main building and an 8-story podium structure is applied as a numerical example to demonstrate the effectiveness of semi-active control with Magneto-Rheological dampers and its comparison with the passive control with the Tuned Mass Damper and two uncoupled buildings and hybrid semi-active control including the Tuned Mass Damper and Magneto-Rheological dampers while they are subject to the earthquake excitation. The numerical results show that semi-active control and hybrid semi-active control can significantly mitigate the seismic responses of both buildings, such as displacement and shear force responses, and fuzzy control technique can effectively mitigate the seismic response of the building complex.

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.

An Experimental Study on Performance Evaluation of Hysteretic Steel Slit Damper (슬릿형 강재이력 감쇠장치의 성능평가를 위한 실험연구)

  • Choi, Ki-Sun;Lee, Hyun-Jee;Kim, Min-Sun;You, Young-Chan
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.1
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    • pp.33-39
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    • 2018
  • This study performed experimental validation of the hysteretic steel slit damper's basic and dependent characteristics, which should be considered for the design. The basic characteristic of the steel slit damper is used for determining design properties of non-linear analysis, such as yielding strength, yielding displacement, elastic stiffness and post-yielding stiffness. In order to evaluate dependent characteristics of the hysteretic steel slit damper, repeated deformation capacity with respect to the displacement, velocity and aspect ratio of the damper was evaluated. In this study, steel slit damper, which is widely used in Korea, was considered. The slit dampers with 55kN and 240kN of yielding strength were produced and tested. It was concluded that the slit damper's hysteresis behavior was affected by the dependent characteristics: displacement, velocity and aspect ratio. In other words, the steel slit damper's behavior was stable within limit displacement, and aspect ratio of the strut affected repeated deformation capacity of the damper subjected to large deformation. In addition, it was observed that the repeated deformation capacity abruptly decreased at the high speed range (${\geq}60mm/sec$). Furthermore, the experimental results were evaluated with the criterion of the damping device specified in ASCE7-10.

Performance Evaluation of Wind Response Control of High-Rise Buildings by Damping and Stiffness of Outrigger Damper System (아웃리거 댐퍼시스템의 감쇠와 강성에 따른 고층 건물 풍응답 제어 성능 평가)

  • Park, Kwang-Seob;Kim, Yun-Tae
    • Journal of Korean Association for Spatial Structures
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    • v.18 no.4
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    • pp.41-48
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    • 2018
  • Recently, the concept of an outrigger damper system with a damper added to the existing outrigger system has been developed and applied for dynamic response control of high-rise buildings. However, the study on the structural characteristics and design method of Outrigger damper system is in the early stages. In this study, a 50 story high - rise building was designed and an outrigger damper system with viscoelastic damper was applied for wind response control. The time history analysis was performed by using the kaimal spectrum to create an artificial wind load for a total of 1,000 seconds at 0.1 second intervals. Analysis of the top horizontal maximum displacement response and acceleration response shows that outrigger damper systems are up to 28.33% and 49.26% more effective than conventional outrigger systems, respectively. Also, it is confirmed that the increase of damping ratio of dampers is effective for dynamic response control. However, since increasing the damping capacity increases the economic burden, it is necessary to select the appropriate stiffness and damping value of the outrigger damper system.

Design and Performance Evaluation of MR Damper for Integrated Isolation Mount (통합제진마운트용 MR 댐퍼의 설계 및 성능 평가)

  • Seong, Min-Sang;Lim, Seung-Gu;Choi, Seung-Bok;Kim, Cheol-Ho;Woo, Je-Kwan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.11
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    • pp.1046-1051
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    • 2010
  • This paper presents design and performance evaluation of magnetorheological(MR) damper for integrated isolation mount. The MR damper needs two functions for the integrated isolation mount. The one is vibration absorption and the other is isolation of vibration transmission. For vibration absorption, the MR damper requires wide damping force range. And for isolation of vibration transmission, the friction of MR damper needs to be eliminated. In order to achieve this goal, a novel type of MR damper is originally designed in this work. Subsequently, the MR damper is mathematically modeled and its damping force characteristics are evaluated. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated. From the result, this paper evaluates the performance of MR damper for integrated isolation mount.

Modeling and Vibration Control of Small-sized Magneto-rheological Damper (소형 MR 댐퍼의 모델링 및 진동제어)

  • Lee, Jong-Woo;Seong, Min-Sang;Woo, Je-Kwan;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.11
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    • pp.1121-1127
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    • 2012
  • This paper presents a new small-sized damper featuring magneto-rheological(MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, the proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

A Study on the Application of the Cutout Piston for the Improvement of the MR Damper's Control Effect (MR 댐퍼의 제어 효과 향상을 위한 Cutout 피스톤 적용에 관한 연구)

  • Kim, Jong-Hyuk;Bae, Jae-Sung;Hwang, Jai-Hyuk;Hong, Yeh-Sun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.506-513
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    • 2011
  • This paper is concerned with a study on the control effect of the MR damper using the cutout piston. The MR damper has passive damping force by the oil pressure and controllable damping force by the magnetic effect. As the velocity of the MR damper's piston increases the passive damping force increases and the ratio of the controllable damping force to the total damping force is decreased. Consequently, the control performance of the MR damper is reduced according to the increase of the velocity. In this paper, the cutout piston concept is applied to the MR damper to improve MR damper's control performance by reducing the passive damping effect. The MR damper with the cutout piston has been designed and manufactured and its hydraulic and electromagnetic analysis has been performed to predict its performance. The control performances of the MR damper with the cutout piston are verified through the comparison of experiment results and simulation results.

Development of Cable Damper System and Its Verification Test (사장교 케이블 댐퍼시스템 개발과 검증실험)

  • Seo, Ju-Won;Kim, Nam-Sik;Suh, Jeong-Gin;Jeong, Woon
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.394-402
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    • 2001
  • In order to lessen cable vibration, new cable damper system with high damping rubber was developed using the basis of the LRB design scheme. The analysis model of cable damper system incorporate voigt-kelvin damper model into the nonlinear cable analysis model. To achieve maximum damping capacity both reducing damper stiffness and developing high damping rubber were performed. As a result of verification test, the high damping rubber damper show its effectiveness in improving cable damping capacity.

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