• Title, Summary, Keyword: 동조질량감쇠기

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Application of MR Damper for Vibration Control of Floor Slab (바닥판 구조물의 진동제어를 위한 MR 감쇠기의 적용)

  • Kim, Gee-Cheol;Kwak, Chul-Seung
    • Journal of the Korean Association for Spatial Structures
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    • v.6 no.3
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    • pp.59-67
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    • 2006
  • A conventional passive TMD is only effective when it is tuned properly. In many practical applications, inevitable off-tuning of a TMD occurs because the mass in a building floor could change by moving furnishings, people gathering, etc. when TMDs are offtuned, TMDs their effectiveness is sharply reduced. Moreover, the off-tuned nTMDs can excessively amplify the vibration levels of the primary structures. This paper discusses the application of a new class of MR damper, for the reduction of floor vibrations due to machine and human movements. The STMD introduced uses a MR damper called to semi-active damper to achieve reduction in the floor vibration. Here, the STMD and the groundhook algorithm are applied to a single degree of freedom system representative of building floors. The performance or the STMD is compared to that or the equivalent passive TMD. In addition, the effects of off-tuning due to variations in the mass of the floor system. Comparison of the results demonstrates the efficiency and robustness or STMD with respect to equivalent TMD.

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The Control of Vertical Vibration of Building Slabs using Tuned Mass Dampers (동조질량 감쇠기에 의한 건물 바닥판의 연직진동제어)

  • 이동근;김진구;안상경
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.4
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    • pp.103-114
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    • 1998
  • The floors of building structures equipped with vibrating machines can be susceptible to large vibration as a result of resonance or beating. Such a vibration can be reduced efficiently by using tuned mass dampers. However, the effectiveness of the damper depends greatly on the location and the natural frequency of the damper. To determine the optimum damper location is especially important since the dynamic behavior of a building structure varies with the location of the input loading. To this end, it is intended to decide the location and natural frequency of tuned mass dampers for reducing vibration of both loaded floors and floors located nearby the loaded floors considering the location and frequency components of the loading. The Vector composition method and the super elements are used th obtain the responses in steady states, and the optimum damper location and natural frequencies were found with the given damper mass.

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Control of the Eccentric Building Using a TMD with Torsional Rigidity (비틀림 강성을 가지는 동조질량감쇠기를 이용한 편심건물의 제어)

  • Park, Yong-Koo;Kim, Hyun-Su;Lee, Dong-Guen
    • Journal of the Korean Association for Spatial Structures
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    • v.12 no.2
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    • pp.65-72
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    • 2012
  • In this stury, control performance of tuned mass damper (TMD) with torsional rigidity for an eccentric structure showing torsional responses is investigated. To this end, an eccentric structure subjected to earthquake excitation is used to evaluate the control performance of torsional TMD by varying installed location and torsional rigidity of TMD, To reduce computational time required for repetitive time history analysis of an example structure having non-proportional damping system due to TMD, an equivalent analytical model is used in this study. Torsional properties of TMD usually neglected in typical TMD are verified to be effective in reduction of torsional responses of the eccentric structure. In the case of eccentric structures, it has been seen that the center of a plane of a structure may not be optimal location of TMD.

Investigation on Seismic-Response Characteristics and Optimal Design Parameters of Tuned Mass Damper Considering Site Effects (지반특성에 따른 동조질량감쇠기의 지진응답특성 및 최적설계변수)

  • Kang, Kyung-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.11
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    • pp.5306-5313
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    • 2011
  • Most previous studies for finding optimal design parameters of a tuned mass damper(TMD) have been focused on the harmonic excited single-degree-of freedom system. In this study, optimal values of damping ratio and tuning frequency ratio of a TMD applied to control a seismically excited structure are investigated through numerical analyses. Considering that the structural responses due to earthquake loads are strongly dependent on the soil condition, the site effects on the optimal parameters of the TMD are studied and compared to those presented by previous studies. Numerical analyses results indicate that better control performance can be obtained by using the parameters proposed by this study in the seismic application of the TMD.

Enhancing Robustness of Floor Vibration Control by Using Asymmetric Tuned Mass Damper (비대칭 동조질량감쇠기를 활용한 바닥진동제어의 강건성 향상 방안)

  • Ko, A Ra;Lee, Cheol Ho;Kim, Sung Yong
    • Journal of Korean Society of Steel Construction
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    • v.26 no.3
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    • pp.177-189
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    • 2014
  • When floor vibration problems occur in existing buildings, TMD (tuned mass damper) can be a viable alternative to resolving the problem. Only when TMD has been exactly tuned to the natural frequency of the floor, it can control the vibration as intended in design. However, TMD gets inefficient in the situation where the natural frequency changes as a result of the uncontrollable variation of the floor mass weight. This physical phenomenon is often called as TMD-off-tuning. This study proposes asymmetric TMD for enhancing the robustness of floor vibration control against uncertain natural frequencies. The proposed TMD features two asymmetric linear springs such that the floor vibrational energy can be dissipated through both the translational and rotational motion. An easy-to-use graphical optimization method was developed in this study. The asymmetric TMD proposed outperformed in vibration control by 28% compared to that of conventional TMD. The robustness of asymmetric TMD of this study was two times higher than that of conventional TMD.

Performance Test of a Tuned Liquid Mass Damper installed in a Real-Scaled Structure (실물크기 구조물에 설치된 동조액체질량감쇠기의 성능실험)

  • Heo, Jae-Sung;Park, Eun-Churn;Lee, Sung-Kyung;Lee, Sang-Hyun;Kim, Hong-Jin;Jo, Ji-Seong;Cho, Bong-Ho;Joo, Seok-Jun;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.2
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    • pp.161-168
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    • 2008
  • In this paper, a tuned liquid mass damper(TLMD) was proposed and experimentally investigated on its control performance, which can control bi-axial responses of building structures by using only one device. The proposed TLMD controls the structural response in a specific one direction by using a liquid sloshing of TLCD. Also, the TLMD reduces the response of structures in the other orthogonal direction by behaving as a TMD that uses mass of the container itself and liquid within container of TLCD installed on linear motion guides. Force-vibration tests on a real-sized structure installed with the TLMD were performed to verify its independent behavior in two orthogonal directions. Test results showed that the responses of a structure were considerably reduced by using the proposed TLMD and its usefulness for structural control in two orthogonal directions.

A Study on the Applicability of Hybrid Mass Damper for the Vibration Control of the Structure under Base Excitation (지반 기진력을 받는 구조물의 진도제어를 위한 Hybrid Mass Damper의 유용성에 관한 연구)

  • 문석준;임채욱;정태영;한성용
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.4
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    • pp.1-8
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    • 2001
  • In this paper, a hybrid mass damper using AC-servomotor was designed and developed in order to reduce vibration levels of a 5-story test structure under base excitation. Control performances of the HMD under random and earthquakes excitations are compared with those of TMD through experimental test. It is confirmed that the HMD is more effective to reduce the vibration levels of the test structure especially for the earthquake excitation which excites more than 2 vibration modes of the structure simultaneously.

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Dynamic Characteristic of A Bi-dirctional Damper Using A Tuned Mass Damper and A Tuned Liquid Column Damper (TMD와 TLCD를 이용한 2방향 감쇠기의 동적특성)

  • Lee, Sung-Kyung;Min, Kyung-Won;Park, Eun-Churn
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.6
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    • pp.589-596
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    • 2008
  • This study introduces the design of a bi-directional damper using a tuned mass damper(TMD) and a tuned liquid column damper(TLCD) and presents experimental verifications to confirm its control performance. The damper used in this study behaves as a TMD in a specific translational direction and acts as a TLCD in the other orthogonal direction. First, shaking table test is performed to investigate the coupled effect of control forces produced by TMD and TLCD. Then, the parameters that affect to dynamic characteristics of the proposed damper are quantitatively evaluated based on the experimental results. Testing results shows that the damper used in this study produces control forces coupled by TLCD and TMD, as it is excited by waves with an incident angle. Also, it is observed that the damper can be used to reduce bi-directional responses of building structures.

Fatigue Reliability Evaluation of Steel-Composite High-Speed Railway Bridge with Tuned Mass Damper (동조질량감쇠기를 장착한 강합성형 고속철도교의 피로신뢰성 평가)

  • Kang, Soo-Chang;Seo, Jeong-Kwan;Koh, Hyun-Moo;Park, Kwan-Soon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.5
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    • pp.1-10
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    • 2005
  • This study proposes a fatigue reliability evaluation procedure for steel-composite high-speed railway bridge based on dynamic analysis and investigates the effectiveness of Tuned Mass Damper(TMD) in terms of the extension of fatigue life of the bridge. For the fatigue reliability evaluation, the limit state is determined using S-N curve and linear fatigue-damage accumulation. Dynamic analyses are peformed repeatedly to consider the uncertainties of train-velocity and damping ratio of the bridge. The distribution of random variables related to fatigue damage for the intended service life is then statistically estimated from analytical results. Finally, the fatigue reliability indices are obtained by means of the Advanced First-Order Second-Moment (AFOSM) method. Through numerical simulation of a steel-composite bridge of 40m span, the effectiveness of TMD on fatigue life of the bridge is examined and the results are presented.

Experimental Evaluation of Design Parameters for TLCD and LCVA (TLCD와 LCVA의 설계파라미터에 대한 실험적 평가)

  • Lee, Sung-Kyung;Min, Kyung-Won;Park, Ji-Hun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.5
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    • pp.403-410
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    • 2009
  • In this paper, damping coefficients and effective masses of tuned liquid-type column dampers were quantitatively evaluated based on experimental results by using system identification technique. First, shaking table tests were performed for two types of tuned liquid-type column dampers. Then, the dynamic characteristics of dampers used in this study were experimentally grasped from harmonic wave excitation testing results of the dampers with various water level. Finally, damping ratios and effective masses of the dampers with varying water level were quantitatively evaluated from minimizing the errors between numerical and experimental results. It was confirmed from system identification results that damping ratio and effective mass are decreased as the water level of dampers is increased.