• Title/Summary/Keyword: passive damper

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Effects of multiple MR dampers controlled by fuzzy-based strategies on structural vibration reduction

  • Wilson, Claudia Mara Dias
    • Structural Engineering and Mechanics
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    • v.41 no.3
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    • pp.349-363
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    • 2012
  • Fuzzy logic based control has recently been proposed for regulating the properties of magnetorheological (MR) dampers in an effort to reduce vibrations of structures subjected to seismic excitations. So far, most studies showing the effectiveness of these algorithms have focused on the use of a single MR damper. Because multiple dampers would be needed in practical applications, this study aims to evaluate the effects of multiple individually tuned fuzzy-controlled MR dampers in reducing responses of a multi-degree-of-freedom structure subjected to seismic motions. Two different fuzzy-control algorithms are considered, a traditional controller where all parameters are kept constant, and a gain-scheduling control strategy. Different damper placement configurations are also considered, as are different numbers of MR dampers. To determine the robustness of the fuzzy controllers developed to changes in ground excitation, the structure selected is subjected to different earthquake records. Responses analyzed include peak and root mean square displacements, accelerations, and interstory drifts. Results obtained with the fuzzy-based control schemes are compared to passive control strategies.

Performance Evaluation of a Large-scale MR Damper for Controlling Seismic Response using a Real-time Hybrid Test Method (실시간 하이브리드 실험법을 이용한 대형 MR감쇠기의 제진 성능평가)

  • Chung, Hee-San;Lee, Sung-Kyung;Park, Eun-Churn;Youn, Kyung-Jo;Min, Kyung-Won;Lee, Heon-Jae;Choi, Kang-Min;Moon, Suk-Jun;Jung, Hyung-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.655-660
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    • 2007
  • This paper presents real-time hybrid test method of large-scale MR damper applied to a building structure under seismic excitation. The real-time hybrid test using an actuator for the control performance evaluation of a MR damper controlling the response of earthquake-excited building structure is experimentally implemented. In the test, the building structure is used as a numerical part, on which a large-scale MR damper adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a MR damper and building structure is measured from the load cell attached on the actuator system and is fed-back to the computer to control the motion of the actuator. Then, the actuator is so driven that the error between the interface displacement computed from the numerical building structure with the excitations of earthquake and the fed-back interface force and that measured from the actuator. The control efficiency of the MR damper used in this paper is experimentally confirmed by implementing this process of experiment on real-time.

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Semi-Active Control of Helicopter Landing Gear using Magneto-Rheological Damper (MR 댐퍼를 이용한 헬기 착륙장치 반능동제어)

  • Hwang, Jae-Up;Hwang, Jae-Hyuk;Bae, Jae-Sung;Hyun, Young-O;Lim, Kyoung-Ho;Kim, Doo-Man;Kim, Tae-Wook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.4
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    • pp.346-351
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    • 2008
  • In this paper, the semi-active control of a helicopter landing gear using magneto -rheological(MR) damper is studied. A dynamic model of the MR damper is formulated by incorporating magnetic field-dependent Bingham properties of the MR fluid. The electromagnet of the MR damper is designed and its magnetic field is analyzed using a commercial finite element code. The damping characteristics of MR damper by changing the intensity of the magnetic field are investigated and the dynamic responses of the helicopter landing gear with MR damper are simulated. The semi-active control of the helicopter landing gear is simulated by implementing a sky-kook control algorithm and its performance is evaluated comparing to the passive control.

Performance Evaluation of a Large-scale MR Damper for Controlling Seismic Responses Using a Real-time Hybrid Test Method (실시간 하이브리드 실험법을 이용한 대형 MR감쇠기의 제진 성능평가)

  • Park, Eun-Churn;Lee, Sung-Kyung;Youn, Kyung-Jo;Chung, Hee-San;Lee, Heon-Jae;Choi, Kang-Min;Moon, Suk-Jun;Jung, Hyung-Jo;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.1
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    • pp.131-138
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    • 2008
  • This paper presents real-time hybrid test method of large-scale MR damper applied to a building structure under seismic excitation. The real-time hybrid test using an actuator for the control performance evaluation of a MR damper controlling the response of earthquake-excited building structure is experimentally implemented. In the test, the building structure is used as a numerical part, on which a large-scale MR damper adopted as an experimental part was installed to reduce its response. At first, the force that is acting between a MR damper and building structure is measured from the load cell attached on the actuator system and is fed-back to the computer to control the motion of the actuator. Then, the actuator is so driven that the error between the interface displacement computed from the numerical building structure with the excitations of earthquake and the fed-back interface force and that measured from the actuator. The control efficiency of the MR damper used in this paper is experimentally confirmed by implementing this process of experiment on real-time.

Passive, semi-active, and active tuned-liquid-column dampers

  • Chen, Yung-Hsiang;Ding, Ying-Jan
    • Structural Engineering and Mechanics
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    • v.30 no.1
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    • pp.1-20
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    • 2008
  • The dynamic characteristics of the passive, semi-active, and active tuned-liquidcolumn dampers (or TLCDs) are studied in this paper. The design of the latter two are based on the first one. A water-head difference (or simply named as water head in this paper) of a passive TLCD is pre-set to form the so-called semi-active one in this paper. The pre-set of water head is released at a proper time instant during an earthquake excitation in order to enhance the vibration reduction of a structure. Two propellers are installed along a shaft inside and at the center of a passive TLCD to form an active one. These two propellers are driven by a servo-motor controlled by a computer to provide the control force. The seismic responses of a five-story shear building with a passive, semiactive, and active TLCDs are computed for demonstration and discussion. The responses of this building with a tuned mass damper (or TMD) are also included for comparison. The small-scale shaking-table experiments of a pendulum-like system with a passive or active TLCD to harmonic and seismic excitations are conducted for verification.

Investigation of the semi-active electromagnetic damper

  • Montazeri-Gh, Morteza;Kavianipour, Omid
    • Smart Structures and Systems
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    • v.13 no.3
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    • pp.419-434
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    • 2014
  • In this paper, the electromagnetic damper (EMD), which is composed of a permanent-magnet rotary DC motor, a ball screw and a nut, is considered to be analyzed as a semi-active damper. The main objective pursued in the paper is to study the two degrees of freedom (DOF) model of the semi-active electromagnetic suspension system (SAEMSS) performance and energy regeneration controlled by on-off and continuous damping control strategies. The nonlinear equations of the SAEMSS must therefore be extracted. The effects of the EMD characteristics on ride comfort, handling performance and road holding for the passive electromagnetic suspension system (PEMSS) are first analyzed and damping control strategies effects on the SAEMSS performance and energy regeneration are investigated next. The results obtained from the simulation show that the SAEMSS provides better performance and more energy regeneration than the PEMSS. Moreover, the results reveal that the on-off hybrid control strategy leads to better performance in comparison with the continuous skyhook control strategy, however, the energy regeneration of the continuous skyhook control strategy is more than that of the on-off hybrid control strategy (except for on-off skyhook control strategy).

Modified Sensitivity Control of a Semi-Active Suspension System with MR-Damper for Ride Comfort Improvement (MR 댐퍼 반능동 현가시스템의 승차감향상을 위한 수정된 민감도제어)

  • Kim, Tae-Shik;Kim, Rae-Kwan;Park, Jae-Woo;Huh, Chang-Do;Hong, Keum-Shik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.1 s.256
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    • pp.129-138
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    • 2007
  • In this paper, a modified sensitivity control for the semi-active suspension system with a magneto-rheological (MR) damper is investigated. A 2-d.o.f quarter-car model together with a 6th order polynomial model for the MR damper is considered. For the purpose of suppressing the vertical acceleration of the sprung mass, the square of the vertical acceleration is defined as a cost function and a modified sensitivity control that updates the current input in the negative gradient of the cost function is proposed. The implementation of the proposed algorithm requires only the measurement of the relative displacement of the suspension deflection. The local stability of equilibria of the closed loop nonlinear system is proved by investigating the eigenvalues of the linearized ones. Through simulations, the passive suspension, the skyhook control, and the proposed modified sensitivity control are compared.

The Application of Resettable Device to Semi-Active Tuned Mass Damper Building Systems for Multi-level Seismic Hazard Mitigation

  • Chey, Min-Ho
    • Architectural research
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    • v.14 no.3
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    • pp.99-108
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    • 2012
  • An innovative multi-story Semi-Active Tuned Mass Damper (SATMD) building system is proposed to control seismic response of existing structures. The application of adding new stories as large tuned mass and semi-active (SA) resettable actuators as central features of the control scheme is derived. For the effective control of the structures, the optimal tuning parameters are considered for the large mass ratio, for which a previously proposed equation is used and the practical optimal stiffness is allocated to the actuator stiffness and rubber bearing stiffness. A two-degree-of freedom (2-DOF) model is adopted to verify the principal efficiency of the suggested structural control concept. The simulations for this study utilizes the three ground motions, from SAC project, having probability of exceedance of 50% in 50 years, 10% in 50 years, and 2% in 50 years for the Los Angeles region. 12-story moment resisting frames, which are modified as '12+2' and '12+4' story structures, are investigated to assess the viability and effectiveness of the system that aims to reduce the response of the buildings to earthquakes. The control ability of the SATMD scheme is compared to that of an uncontrolled and an ideal Passive Tuned Mass Damper (PTMD) building system. From the performance results of suggested '12+2' and '12+4' story retrofitting case studies, SATMD systems shows significant promise for application of structural control where extra stories might be added.

Monte Carlo Simulation of MR Damper Landing Gear Taxiing Mode under Nonstationary Random Excitation

  • Lee, Hyo-Sang;Jang, Dae-Sung;Hwang, Jai-Hyuk
    • Journal of Aerospace System Engineering
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    • v.14 no.4
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    • pp.10-17
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    • 2020
  • When an aircraft is taxiing, excitation force is applied according to the shape of the road surface. The sprung mass acceleration caused by the excitation of the road surface negatively affects the feeling of boarding. This paper addresses the verification process of the semi-active control method applied to improve the feeling of boarding. The Magneto-Rheological damper landing gear model is employed alongside the control method. It is a Oleo-Pneumatic damper filled with a fluid having the characteristics of increasing yield stress when subjected to a magnetic field. The control method involves verifying Skyhook Control Type2 developed by Skyhook control. The Sinozuka white noise model that considers runway characteristics was employed for the road surface in the simulation. The runway road surface obtained through this model has stochastic characteristics, so the dynamic characteristics were analyzed by applying Monte-Carlo simulation. A dynamic analysis was conducted by co-simulating the landing gear model made by RecurDyn and the control method designed by Simulink. Simulation results show that the Skyhook Control Type2 method has the best control effect in the low speed range compared to the passive type (without control) and skyhook control.

A new control approach for seismic control of buildings equipped with active mass damper: Optimal fractional-order brain emotional learning-based intelligent controller

  • Abbas-Ali Zamani;Sadegh Etedali
    • Structural Engineering and Mechanics
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    • v.87 no.4
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    • pp.305-315
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    • 2023
  • The idea of the combination of the fractional-order operators with the brain emotional learning-based intelligent controller (BELBIC) is developed for implementation in seismic-excited structures equipped with active mass damper (AMD). For this purpose, a new design framework of the mentioned combination namely fractional-order BEBIC (FOBELBIC) is proposed based on a modified-teaching-learning-based optimization (MTLBO) algorithm. The seismic performance of the proposed controller is then evaluated for a 15-story building equipped with AMD subjected to two far-field and two near-field earthquakes. An optimal BELBIC based on the MTLBO algorithm is also introduced for comparison purposes. In comparison with the structure equipped with a passive tuned mass damper (TMD), an average reduction of 44.7% and 42.8% are obtained in terms of the maximum absolute and RMS top floor displacement for FOBELBIC, while these reductions are obtained as 30.4% and 30.1% for the optimal BELBIC, respectively. Similarly, the optimal FOBELBIC results in an average reduction of 42.6% and 39.4% in terms of the maximum absolute and RMS top floor acceleration, while these reductions are given as 37.9% and 30.5%, for the optimal BELBIC, respectively. Consequently, the superiority of the FOBELBIC over the BELBIC is concluded in the reduction of maximum and RMS seismic responses.