• Title, Summary, Keyword: bi-directional damper

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Experiment of a Liquid Damper Controlling Bi-directional Wind Responses of a Tall Building (초고층 건물의 양방향 풍응답 제어를 위한 액체댐퍼 실험)

  • Lee, Hye-Ri;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.3
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    • pp.287-295
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    • 2010
  • This study deals with the design of a bi-directional damper using a tuned liquid damper(TLD) and a tuned liquid column damper(TLCD) for a SDOF building. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with a single damper. The damper used in this study behaves as both a TLCD in a specific translational direction and a TLD in the other orthogonal direction. This paper presents experimental verification to confirm its control performance. First, shaking table test is carried out to investigate reducing responses by the damper. Control performance of the damper is expressed by the transfer function from shaking table accelerations to SDOF building ones. Testing results show that the damper reduced bi-directional responses of a SDOF building. Also, it reduced torsion responses.

Design Parameter of a New Type Bi-directional Damper Using a Tuned Liquid Column Damper and a Tuned Sloshing Damper (TLCD와 TSD를 이용한 새로운 형태의 양방향 감쇠기 설계변수)

  • Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.8
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    • pp.850-856
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    • 2009
  • A new type bi-directional damper using a tuned liquid column damper(TLCD) and a tuned sloshing damper(TSD) is introduced in this study. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with one damper. One of objectives of this study is to derive analytical dynamics to investigate coupled effects due to TLCD and TSD. Another objective is to address the effect of coupled control force due to TLCD and TSD on the dynamic characteristic of the damper based on analytical dynamics. Shaking table test is undertaken to experimentally grasp dynamic characteristics of the damper under white noise excitation. Its dynamic characteristic is expressed by the transfer function from the shaking table acceleration to the control force generated from the damper. Finally, its design parameters are identified based on the coupled dynamics, which include the mass ratio of horizontal liquid column to total liquid for a TLCD, the participation factor of the fundamental liquid sloshing for a TSD and damping ratio for both cases.

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.

A Tuned Liquid Mass Damper(TLMD) for Controlling Bi-directional Responses of a Building Structure (건축구조물의 2방향 진동제어를 위한 동조액체질량감쇠기)

  • Heo, Jae-Sung;Park, Eun-Churn;Lee, Sang-Hyun;Lee, Sung-Kyung;Kim, Hong-Jin;Cho, Bong-Ho;Jo, Ji-Seong;Kim, Dong-Young;Min, Kyung-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.3
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    • pp.345-355
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    • 2008
  • This paper presents a design of a tuned liquid mass damper(TLMD) for controlling bi-directional response of high-rise building structure subjected to windload. The proposed damper behaves as a tuned mass damper(TMD) of which mass is regarded as the mass of a tuned liquid column damper(TLCD) and the case wall of the TLCD itself in one direction and the TLCD in the other direction. Because the proposed device has coupled design parameter along two orthogonal directions, it is very important to select designing components by optimal fine tuning. In the designing TLMD, for easy maintenance, the rubber-bearing with small springs was applied in TMD direction. In this study, the Songdo New City Tower 1A in Korea, which has been designed and constructed two TLCDs in order to control bi-directional response, was chosen as the model building structure. The results of rotation test proved the effectiveness of bi-directional behavior of TLMD.

Performance Evaluation of Tuned Liquid Mass Damper for Reducing Bi-directional Responses of a Building Structure (건축구조물의 2방향 진동제어를 위한 TLMD 제어성능평가)

  • Heo, Jae-Sung;Lee, Sung-Kyung;Park, Eun-Churn;Lee, Sang-Hyun;Kim, Hong-Jin;Jo, Ji-Seong;Cho, Bong-Ho;Min, Kyung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.432-441
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    • 2008
  • In this study, the control performance of a Tuned Liquid Mass Damper(TLMD) manufactured to reduce the orthogonal bi-directional responses of building structures was experimentally evaluated. the TLMD using only one control device reduce bi-directional responses of building structures by making the TLMD behave as TMD and TLCD to the strong and weak axial direction of building structures. first, the control performance was evaluated by forcing sinusoidal waves to a test model that the TLMD is installed on the scale-downed building structure. Second, the real-time hybrid shaking table test was performed to evaluate the performance of the vibration control system made up of numerical part as a scale-downed building structural model and a physical experimental part as a TLMD. the superiority of bi-directional vibration control performance of the manufactured TLMD was verified by comparing the uncontrolled and controlled results of these tests.

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Performance of a 3D pendulum tuned mass damper in offshore wind turbines under multiple hazards and system variations

  • Sun, Chao;Jahangiri, Vahid;Sun, Hui
    • Smart Structures and Systems
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    • v.24 no.1
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    • pp.53-65
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    • 2019
  • Misaligned wind-wave and seismic loading render offshore wind turbines suffering from excessive bi-directional vibration. However, most of existing research in this field focused on unidirectional vibration mitigation, which is insufficient for research and real application. Based on the authors' previous work (Sun and Jahangiri 2018), the present study uses a three dimensional pendulum tuned mass damper (3d-PTMD) to mitigate the nacelle structural response in the fore-aft and side-side directions under wind, wave and near-fault ground motions. An analytical model of the offshore wind turbine coupled with the 3d-PTMD is established wherein the interaction between the blades and the tower is modelled. Aerodynamic loading is computed using the Blade Element Momentum (BEM) method where the Prandtl's tip loss factor and the Glauert correction are considered. Wave loading is computed using Morison equation in collaboration with the strip theory. Performance of the 3d-PTMD is examined on a National Renewable Energy Lab (NREL) monopile 5 MW baseline wind turbine under misaligned wind-wave and near-fault ground motions. The robustness of the mitigation performance of the 3d-PTMD under system variations is studied. Dual linear TMDs are used for comparison. Research results show that the 3d-PTMD responds more rapidly and provides better mitigation of the bi-directional response caused by misaligned wind, wave and near-fault ground motions. Under system variations, the 3d-PTMD is found to be more robust than the dual linear TMDs to overcome the detuning effect. Moreover, the 3d-PTMD with a mass ratio of 2% can mitigate the short-term fatigue damage of the offshore wind turbine tower by up to 90%.

Bi-directional response control of a building using one TLD (1 개의 TLD 를 이용한 건물의 양방향 진동제어)

  • Min, Kyung-Won;Lee, Sung-Kyung;Park, Eun-Churn
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.119-124
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    • 2009
  • This paper proposes a tuned liquid column sloshing damper(TLCSD) and presents experimental results to evaluate its control performance. The proposed damper acts as a tuned liquid column damper(TLCD) and a tuned liquid damper(TLD), respectively, in both principal axes of building structures. Shaking table test was performed to grasp its dynamic characteristics. Testing results showed that under inclined incident excitations, a TLCSD used in this study have dynamic characteristics coupled by both TLCD and TLD.

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Optimal assessment and location of tuned mass dampers for seismic response control of a plan-asymmetrical building

  • Desu, Nagendra Babu;Dutta, Anjan;Deb, S.K.
    • Structural Engineering and Mechanics
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    • v.26 no.4
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    • pp.459-477
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    • 2007
  • A bi-directional tuned mass damper (BTMD) in which a mass connected by two translational springs and two viscous dampers in two orthogonal directions has been introduced to control coupled lateral and torsional vibrations of asymmetric building. An efficient control strategy has been presented in this context to control displacements as well as acceleration responses of asymmetric buildings having asymmetry in both plan and elevation. The building is idealized as a simplified 3D model with two translational and a rotational degrees of freedom for each floor. The principles of rigid body transformation have been incorporated to account for eccentricity between center of mass and center of rigidity. The effective and robust design of BTMD for controlling the vibrations in structures has been presented. The redundancy of optimum design has been checked. Non dominated sorting genetic algorithm (NSGA) has been used for tuning optimum stages and locations of BTMDs and its parameters for control of vibration of seismically excited buildings. The optimal locations have been observed to be reasonably compact and practically implementable.

Reducing bi-directional response of SDOF building by new type Tuned Liquid Damper (새로운 형태의 동조액체댐퍼에 의한 단자유도 건물의 양방향 응답제어)

  • Lee, Hye-Ri;Min, Kyung-Won
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.778-782
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    • 2010
  • 본 논문에서는 TLD와 TLCD를 사용한 하나의 액체 감쇠기를 이용하여 건물의 양방향 응답 제어를 연구하였다. 초고층 건물이 풍하중을 받을때는 풍방향과 풍직각방향으로 진동하여 두 개의 댐퍼를 필요로 한다. 이 논문에서 제안된 댐퍼는 건물의 양방향 응답을 하나의 감쇠기로 제어할 수 있다는 장점이 있다. 이 댐퍼의 TLCD는 건물의 주축방향으로 TLD는 주축으로 직각되는 다른 방향으로 거동을 하게 된다. 실험을 통해 양방향 감쇠기를 사용하여 건물의 양방향 응답제어를 증명하였다. 첫 번째로 양방향 감쇠기에 의한 건물의 응답제어를 알기 위한 진동대 실험을 실시하였다. 진동대 가속도를 입력으로 하고 단자유도 건물의 가속도를 출력으로 하는 전달함수를 통해 결과를 나타내었다. 실험 결과 이 연구에서 제안된 감쇠기는 단자유도 건물의 양방향 응답을 제어하였고, 비틀림 응답도 제어 하였다.

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Inelastic Seismic Response Control of the RC Framed Apartment Building Structures Using Exterior-Installed Kagome Damping System (외부접합형 카고메 감쇠시스템을 사용한 철근콘크리트 라멘조 공동주택 비탄성 지진 응답 제어)

  • Hur, Moo-Won;Chun, Young-Soo;Lee, Sang-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.3
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    • pp.58-65
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    • 2016
  • Various passive energy dissipation systems have been proposed and widely applied to real building structures under seismic load due to their high energy-dissipation potential and low cost for installation and maintenance. This paper presents nonlinear dynamic analysis results of the effectiveness of exterior-installed Kagome damping system(EKDS) in passively reducing seismic response. Kagome damping system proposed by previous studies has isotropic and bi-linear hysteretic characteristics and the installation configuration is newly presented in this study. The 15 and 20 story RC framed apartment buildings are used for verifying the effectiveness of the EKDS. The stiffness ratio of the damper supporting column to the original building, the number of the dampers, and the installed stories were considered as design parameters. Numerical results demonstrated that the EKDS were very effective in reducing both the two horizontal directional seismic responses by just using smaller number of exterior-installed damping system when compared to the traditional one-directional inter-story installed damping systems.