• 제목/요약/키워드: eddy current damping

검색결과 26건 처리시간 0.031초

Experimental study on the effect of EC-TMD on the vibration control of plant structure of PSPPs

  • Zhong, Tengfei;Feng, Xin;Zhang, Yu;Zhou, Jing
    • Smart Structures and Systems
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    • 제29권3호
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    • pp.457-473
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    • 2022
  • A high-frequency vibration control method is proposed in this paper for Pumped Storage Power Plants (PSPPs) using Eddy Current Tuned Mass Damper (EC-TMD), based on which a new type of EC-TMD device is designed. The eddy current damper parameters are optimized by numerical simulation. On this basis, physical simulation model tests are conducted to compare and study the effect of structural performance with and without damping, different control strategies, and different arrangement positions of TMD. The test results show that EC-TMD can effectively reduce the control effect under high-frequency vibration of the plant structure, and after the additional damping device forms EC-TMD, the energy dissipation is further realized due to the intervention of eddy current damping, and the control effect is subsequently improved. The Multi-Tuned Mass Damper (MTMD) control strategy broadens the tuning band to improve the robustness of the system, and the vibration advantage is more obvious. Also, some suggestions are made for the placement of the dampers to promote their application.

Design and application of a novel eddy current damper for a high-rise sightseeing tower

  • Kaifang Liu;Yanhui Liu;Chia-Ming Chang;Ping Tan
    • Structural Engineering and Mechanics
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    • 제86권4호
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    • pp.573-587
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    • 2023
  • A conventional tuned mass damper (TMD) provides a passive control option to suppress the structures' wind- or earthquake-induced vibrations. However, excessive displacements of the TMD raise concerns in the practical implementation. Therefore, this study proposes a novel TMD designed for and deployed on a high-rise sightseeing tower. The device consists of an integrated two-way slide rail mount and an eddy current damper (ECD) with a stroke control mechanism. This stroke control mechanism allows the damping coefficient to automatically increase when the stroke reaches a predetermined value, preventing excessive damper displacements during large earthquakes. The corresponding two-stage damping parameters are designed with a variable-thickness copper plate to enable the TMD stroke within a specified range. Thus, this study discusses the detailed design schemes of the device components in TMD. The designed two-stage damping parameters are also numerically verified, and the structural responses with/without the TMD are compared. As seen in the results, the proposed TMD yields effective control authority to limit the acceleration response within a comfort level. In addition, this TMD resolves the spatial availability for the damper movement in high-rise buildings by the controllable damping mechanism.

와전류 충격완충장치의 실험적 동특성 연구 (Experimental Study for Dynamic Characteristics of Eddy Current Shock Absorber)

  • 곽동기;황재혁;배재성
    • 한국항공우주학회지
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    • 제35권12호
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    • pp.1089-1094
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    • 2007
  • 연구에서는 코일 스프링 및 작동유체가 없는 새로운 감쇠기의 개념을 소개한다. 이 감쇠기는 영구자석과 전도체 실린더로 구성된다. 극성이 반대인 자석은 반발력을 발생시키고, 이는 코일 스프링과 같은 역할을 한다. 영구자석과 전도체 실린더 사이의 상대운동은 기전력을 발생시키는 와전류를 생성하고, 이로 인해 감쇠 유체를 대신할 수 있는 감쇠력을 만든다. 이러한 감쇠를 와전류 감쇠기라고 한다. 본 연구에서 제안된 와전류 감쇠기의 중요한 장점은 감쇠 유체 및 어떠한 외부의 전력도 필요로 하지 않고, 비접촉식이며, 온도에도 민감하지 않다. 본 연구에서는 제안된 와전류 감쇠기를 제작하고 실험을 통하여 감쇠기의 동적 특성을 조사하였다. 본 연구의 결과는 제안된 와전류 감쇠기가 우수한 감쇠 성능을 가짐을 보였다.

Enhance the damping density of eddy current and electromagnetic dampers

  • Li, Jin-Yang;Zhu, Songye;Shen, Jiayang
    • Smart Structures and Systems
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    • 제24권1호
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    • pp.15-26
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    • 2019
  • Over the past decades, a great variety of dampers have been developed and applied to mechanical, aerospace, and civil structures to control structural vibrations. This study is focused on two emerging damper types, namely, eddy current dampers (ECDs) and electromagnetic damper (EMDs), both of which are regarded as promising alternatives to commonly-applied viscous fluid dampers (VFDs) because of their similar mechanical behavior. This study aims to enhance the damping densities of ECDs and EMDs, which are typically lower than those of VFDs, by proposing new designs with multiple improvement measures. The design configurations, mechanisms, and experimental results of the new ECDs and EMDs are presented in this paper. The further comparison based on the experimental results revealed that the damping densities of the proposed ECD and EMD designs are comparable to those of market-available VFDs. Considering ECDs and EMDs are solid-state dampers without fluid leakage problems, the results obtained in this study demonstrate a great prospect of replacing conventional VFDs with the improved ECDs and EMDs in future large-scale applications.

와전류를 이용한 에너지 포집의 개념과 모델 (Concept and Model of Energy Harvesting using Eddy Current)

  • 한지훈;박성근;주광일;임승현;오일권
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.3506-3511
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    • 2007
  • The energy harvesting using smart materials has been extensively investigated to supply electric power to wireless sensor systems. In this paper, the energy harvesting using eddy current was studied with the integrated magnetic cantilever beam system. If a large conductive metal plate moves through a magnetic field which intersects perpendicularly to the sheet, the magnetic field will induce small rings of current which will actually create internal magnetic fields opposing the change. This eddy current that was induced in the coiled conductive sheet from the mechanical vibration was converted to chemical energy by charging batteries. The experimental results show that the eddy current generated the electric power up to max 31.2mW. Additionally the vibration reduction of the mechanical cantilever beam was observed by the energy dissipation in the electro-magnetic coupled system. The present result shows that the vibration level of the first natural frequency was reduced up to 7.7dB

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Mitigation of wind-induced responses of cylinder solar tower by a tiny eddy current tuned mass damper based on elastic wind tunnel tests

  • Liu, Min;Li, Shouying;Chen, Zhengqing
    • Smart Structures and Systems
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    • 제26권5호
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    • pp.619-629
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    • 2020
  • Solar towers, which often has a large aspect ratio and low fundamental natural frequency, were extremely prone to large amplitude of wind-induced vibrations, especially Vortex-Induced Vibration (VIV). A tiny Tuned Mass Damper (TMD) with conveniently adjustable eddy current damping was specially designed and manufactured for elastic wind tunnel tests of a solar tower. A series of numerical simulations by using the COMSOL software were conducted to determine three key parameters, including the thickness of the back iron plate and the conductive plate (Tb and Tc), the distance between the magnet and the conductive plate (Td). Based on the results of numerical simulations, a tiny TMD was manufactured and its structural parameters were experimentally identified. The optimized values of the tiny TMD can be conveniently realized. The tiny TMD was installed at the top of the elastic test model of a 243-meter-high solar tower, and a series of wind tunnel tests were carried out to examine the effectiveness of the TMD in suppressing wind-induced responses of the test model. The results showed that the wind-induced responses could be obviously reduced by the TMD, especially in the cross-wind direction. The cross-wind RMS and peak responses at the critical wind velocity can be reduced by about 86% and 75%, respectively. However, the maximum reduction of the responses at the design wind velocity is about 45%, obviously less than that at the critical wind velocity.

고속 차량 충돌 사고 대비를 위한 충격 흡수용 자기식 댐퍼 설계 (Design of a New Linear Magnetic Damper for Shock-Absorbing from Crash Accident of High Speed Vehicles)

  • 이헌;김용대;왕세명;박기환
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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    • pp.653-654
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    • 2006
  • This paper proposes a new linear magnetic damper for absorbing shock from a crash accident involving high speed vehicles. The magnetic damper is composed of a conductive plate, a yoke and permanent magnets which are constructed to a Halbach array to improve the damping force. In order to calculate the damping force, finite element analysis(FEA) using J-Mag, a commercial FEA tool, is performed and the results are validated by the experiment. Also, the design optimization of the plate generating the eddy current causing the damping force performed to obtain the most efficient damping force. Finally, the specifications and the performance of the proposed magnetic damper are represented.

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와전류 감쇠기를 적용한 평판의 진동 저감에 관한 실험적 연구 (A Experimental Study on Vibration Attenuation of a Plate with Eddy Current Damper)

  • 편봉도;김종혁;배재성;황재혁
    • 한국항공우주학회지
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    • 제48권5호
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    • pp.355-361
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    • 2020
  • 인공위성 중 군사적 성격을 띠는 저궤도 소형 인공위성의 경우 다표적 관측을 필요로 하고 고해상도의 사진 및 영상의 수요가 증가하는 추세이다. 고해상도 영상과 다표적 관측을 위해 인공위성의 기동성이 가장 큰 변수로 작용한다. 소형 인공위성의 경우 고기동성을 갖게 되면 빠르게 자세기동을 할 수 있지만 자세 기동을 완료 후 다음 자세 기동을 할 때 잔류진동이 발생하게 된다. 이에 본 연구에서 자세 기동 후 발생하는 평판의 진동 특성을 검증하기 위하여 자세기동을 모사하기 위한 실험 치구를 제작하고 실험을 수행하였다. 추가로 이러한 진동을 저감시키기 위해 영구자석을 이용한 수동형 감쇠방법으로 와전류 브레이크 시스템을 응용한 와전류 감쇠기를 제시하였다. 와전류 감쇠기를 적용하기 위하여 수학적 모델을 정립하였으며 영구자석의 자속밀도와 공극거리에 따라 이를 실험적으로 구현하였으며, 4개의 태양전지판(평판) 중 1개 평판을 특정하여 와전류감쇠기를 적용유무에 따라 자세 기동 후 발생하는 잔류진동에 대한 저감 성능을 실험적으로 검증하였다.

자기효과를 이용한 충격흡수장치의 감쇠계수에 관한 연구 (Study on Damping Coefficient of Shock Absorber with Magnetic Effects)

  • 이미선;배재성;황재혁;황도순
    • 한국항공우주학회지
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    • 제39권9호
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    • pp.832-838
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    • 2011
  • 본 연구는 달착륙선의 착륙장치 개발 연구로써 자기효과를 이용한 충격흡수장치를 제안한다. 충격흡수장치는 금속튜브와 피스톤 로드(piston rod), 피스톤 로드를 따라 가진되는 영구자석으로 구성되며 금속튜브와 영구자석사이에 존재하는 자기력과 상대운동에 의해 발생되는 와전류 효과 등의 자기효과를 이용하여 충격에너지를 분산 및 소산시킨다. 또한 자석을 같은 극을 마주보게 배치함으로써 코일 스프링과 유사한 충격흡수 효과를 얻을 수 있다. 이 장치는 구조가 단순하고 오일이나 가스의 사용이 불필요하므로 우주공간에서 사용이 용이하다. 자기 효과를 이용한 충격흡수장치의 감쇠와 스프링 특성을 전자기학 이론과 유한요소해석을 통하여 관찰하고 장치를 설계, 제작하여 실험을 수행한 결과와 비교분석하였다.