• Title, Summary, Keyword: 동조액체감쇠기

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Development of Variable Voltage Sensing for Identification of Dynamic Characteristics of TLCDs (동조액체기둥감쇠기의 동적특성을 파악하기 위한 가변전압측정 시스템 개발)

  • Jang, Seok-Jung;Kim, Jun-Hee;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.3
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    • pp.275-281
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    • 2015
  • In this study, vertical motion of a Tuned Liquid Column Damper(TLCD) is measured by a variable voltage measurement system in the electric field and design parameters of the TLCD are determined. First, nonlinear damping term of the TLCD is replaced as the equivalent viscous damping term. The natural frequency and damping ratio of dynamic characteristics of the TLCD are verified. In addition, a novel liquid level measurement system is developed for measuring vertical motion of the TLCD. For the experimental achievement, experimental characterizations of natural frequency and damping ratio of the TLCD are undertaken utilizing the developed variable voltage sensing. Also, shake table testing is performed to determine the dynamic characteristics of the TLCD. As a result, the feasibility of the proposed liquid level measurement system is verified by comparison with the capacitive type wavemeter.

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.

Numerical Study on Bituning of Acoustic Resonator in a Combustion Chamber of Liquid Rocket Engine (로켓엔진 연소실에 장착된 음향 공명기의 bituning에 관한 수치적 연구)

  • Sohn Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.355-358
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    • 2006
  • A linear acoustic analysis is conducted to examine bituning of acoustic resonators for acoustic damping in a combustion chamber of liquid rocket engine. Bituned resonators are tuned to the two principal modes, the first tangential(1T) and the first radial(1R) modes. First, the acoustic-damping effect of monotuned resonators is investigated. The damping capacity is quantified by damping factor as a function of the number of the resonators monotuned to 1T or 1R mode. Next, the damping characteristics of the bituned resonators are investigated. From the numerical data, the number of resonators, to be tuned to 1T and 1R modes, respectively, can be selected properly.

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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.

A Numerical Study on Bituning of Acoustic Resonator in a Combustion Chamber of Liquid Rocket Engine (로켓엔진 연소기에서 음향 공명기의 bituning에 관한 수치적 연구)

  • Lee Su-Ryong;Sohn Chae-Hoon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.1
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    • pp.1-8
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    • 2006
  • A linear acoustic analysis is conducted to examine bituning of acoustic resonators for acoustic damping in a combustion chamber of liquid rocket engine. Bituned resonators are tuned to the two principal modes, the first tangential(1T) and the first radial(1R) modes. First, the acoustic-damping effect of monotuned resonators is investigated. The damping capacity is quantified by damping factor as a function of the number of the resonators monotuned to 1T or 1R mode. Next, the damping characteristics of the bituned resonators are investigated. From the numerical data, the number of resonators, to be tuned to 1T and 1R modes, respectively, can be selected properly. Furthermore, the concept of resonator bituning is applied to reduce the degradation of damping effect caused by the mode split and thereby, optimal bituning frequencies are found.

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, Sang-Hyun;Lee, Sung-Kyung;Min, Kyung-Won;Kim, Hong-Jin;Jo, Ji-Seong;Cho, Bong-Ho;Joo, Seok-Jun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.449-457
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    • 2008
  • In this paper, a tuned liquid1) 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.

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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.

Acoustic-Damping Characteristics of Half-Wave Resonator in a Combustion Chamber of Liquid Rocket Engine (로켓엔진 연소기에서 반파장 공명기의 음향감쇠에 관한 수치적 연구)

  • Sohn Chae-Hoon;Park I-Sun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.4
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    • pp.9-15
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    • 2005
  • A linear acoustic analysis is performed to explore the characteristics of acoustic damping by a gas-liquid scheme coaxial injector in a liquid rocket engine. The injector can play a role of acoustic resonator. Acoustic-damping characteristics of half-wave resonator are compared with those of quarter-wave resonator. Various effects of the boundary absorption coefficient, injector length and sound speed in combustion chamber and resonator are investigated. As a result, short tuning length of resonator and low sound speed of the medium have a favorable effect on acoustic damping. As the boundary absorption coefficient decreases, the tuning range of the resonator length becomes narrower.

Seismic Performance of SDF Systems with Tuned Liquid Damper Subjected to Ground Motions (지진 하중에 대한 동조액체감쇠기 성능 수치해석 검토)

  • Han, Sang-Whan;Oh, Seung-Bo;Ha, Sung-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.3
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    • pp.261-268
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    • 2016
  • Tuned Liquid Dampers(TLD) are energy dissipation devices that have been proposed to control the dynamics response of structure. The TLD has been shown to effectively control the wind response of structures. However, controlling responses of structures with TLD under seismic loads are not fully investigated. The objective of this study is to evaluate the seismic performance of single degree of freedom(SDF) with TLDs having various tuning and mass raitos. For this purpose, analytical studies are conducted. Different soil conditions are considered in this study. As a result, performance of TLD, appeared diffrently depending on the natural period, damping ratio of the structure. Also TLD tuning ratio appeared differently.

Measurement System of Dynamic Liquid Motion using a Laser Doppler Vibrometer and Galvanometer Scanner (액체거동의 비접촉 다점측정을 위한 레이저진동계와 갈바노미터스캐너 계측시스템)

  • Kim, Junhee;Shin, Yoon-Soo;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.5
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    • pp.227-234
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    • 2018
  • Researches regarding measurement and control of the dynamic behavior of liquid such as sloshing have been actively on undertaken in various engineering fields. Liquid vibration is being measured in the study of tuned liquid dampers(TLDs), which attenuates wind motion of buildings even in building structures. To overcome the limitations of existing wave height measurement sensors, a method of measuring liquid vibration in a TLD using a laser Doppler vibrometer(LDV) and galvanometer scanner is proposed in this paper: the principle of measuring speed and displacement is discussed; a system of multi-point measurement with a single point of LDV according to the operating principles of the galvanometer scanner is established. 4-point liquid vibration on the TLD is measured, and the time domain data of each point is compared with the conventional video sensing data. It was confirmed that the waveform is transformed into the traveling wave and the standing wave. In addition, the data with measurement delay are cross-correlated to perform singular value decomposition. The natural frequencies and mode shapes are compared using theoretical and video sensing results.