• Title/Summary/Keyword: Magnetic-Rheological Fluid

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Response Property of Multi-directional Mount Using Magneto-Rheological Fluid (MR유체를 이용한 다방향 제진형 마운트의 응답특성)

  • 안영공;신동춘;양보석;이일영;김동조
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.7
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    • pp.517-523
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    • 2003
  • This paper presents response property of the squeeze mode type mount using Magneto-Rheological fluid (MR fluid) . The MR mount for the isolation of multi-directional vibrations was constructed in this study. Both the mechanism and shape of the mount are the same as squeeze film dampers for a rotor system. In the present work, the performance of the mount was experimentally Investigated according to the magnetic field strength. The experimental results present that the MR mount can effectively reduce the vibration in a wide range of frequency by controlling the applied electromagnetic filed strength. Viscous damping and stiffness coefficients of the MR mount tend to be changed according to the variation of the applied currents In this study.

The Evaluation of Shock Absorption Performance of Magneto-Rheological Elastomer Through the Drop Impact Test (낙하 충격 실험을 통한 자기유변탄성체의 충격 흡수 성능 평가)

  • Joeng, Kyeong Sik;Lee, Chul Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.92-93
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    • 2013
  • In this study, Shock Absorption performance of Magneto-rheological elastomer(MRE) is identified through the drop impact test. Magneto-rheological materials are divided into two groups by MR fluid in fluid state and MR elastomer in solid state like rubber. The stiffness characteristics of Magneto-rheological material can be changed as magnetic field is applied. The impact loads in MR elastomer were measured under weight of impactor. Experiment results are shown through the experiments to confirm the effect of shock absorption of MR elastomer. Thus, the MR elastomer can be applied to shock absorber used in area that shock occurs.

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Analysis of Magneto-rheological Fluid Based Semi-active Squeeze Film Damper and its Application to Unbalance Response Control of Rotor (자기유변유체를 이용한 반능동형 스퀴즈 필름 댐퍼의 해석 및 회전체 불균형 응답 제어)

  • Kim, Keun-Joo;Lee, Chong-Won
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.3 s.96
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    • pp.354-363
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    • 2005
  • Squeeze film dampers (SFDs) have been commonly used to effectively enhance the dynamic behavior of the rotating shaft supported by rolling element bearings. However, due to the recent trends of high operating speed, high load capacity and light weight in rotating machinery, it is becoming increasingly important to change the dynamic characteristics of rotating machines in operation so that the excessive vibrations, which may occurparticularly when passing through critical speeds or unstable regions, can be avoided. Semi-active type SFDs using magneto-rheological fluid (MR fluid), which responds to an applied magnetic field with a change in rheological behavior, are introduced in order to find its applications to rotating machinery as an effective device attenuating unbalance responses. In this paper, a semi-active SFD using MR fluid is designed, tested, and identified to investigate the capability of changing its dynamic properties such as damping and stiffness.In order to apply the MR-SFD to the vibration attenuation of a rotor, a systematic approach for determining the damper's optimal location is investigated, and also, a control algorithm that could improve the unbalance response characteristics of a flexible rotor is proposed and its control performance is validated with a numerical example.

Development of Semi-active Damper by Magneto-Rheological Fluid (자기 유변 유체를 이용한 반능동 감쇠기의 개발)

  • 정병보;권순우;김상화;박영진
    • The Korean Journal of Rheology
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    • v.11 no.2
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    • pp.105-111
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    • 1999
  • Dampers have been used to dissipate energy in mechanical systems. There are several types of dampers such as passive, active, and semi-active damper. Semi-active dampers have higher performance than passive ones and require less power to operate than active ones. Their damping characteristics can be changed properly for varying conditions. In this paper, we investigated the semi-active damper using Magneto-Rheological fluid. Magneto-Rheological fluid, which is one of controllable fluids, changes its damping and rheological characteristics from Newtonian fluid to Bingham fluid as the magnetic field is applied. It has several advantages such as high yield strength, low viscosity, robustness to impurities and wide temperature range of stability. If we designe a semi-active damper by using this material, we can not only design a simply structured damper but also expect rapid response. In this study, we propose several types of semi-active dampers which are designed and manufactured using Magneto-Rheological fluid and some problems encountered during their applications.

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Propose, Design and Control of a New Actuator Using MR Fluid (MR 유체를 이용한 새로운 액추에이터의 제안, 설계 및 제어)

  • Kim J.S.;Ahn K.K.;Kha N.B.;Ahn Y.K.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.111-112
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    • 2006
  • A new MR cylinder with built-in valves using Magneto - Rheological fluid (MR valve) is proposed for fluid power control systems. The MR fluid is a newly developed functional fluid whose obvious viscosity is controlled by the applied magnetic field intensity. This MR cylinder, which is composed of cylinder with small clearance and piston with electromagnet, has the characteristics of simple, compact and reliable structure. This paper presents a method to control the pressure of MR cylinder by using Generalized Predictive Control (GPC) algorithm. The differential pressure is controlled by applying magnetic field intensity to MR fluid. The use of GPC controller is to generate a control sequence by minimizing a cost function in such a way that the future system output is driven close to reference over finite prediction horizons. Experimental results from real time control using GPC method compared with conventional PID control method are also shown in this paper.

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Tactile Response Characteristics of Haptic Displays based on Magneto-Rheological Fluids (MR 유체를 이용한 햅틱 디스플레이의 질감 반응 특성)

  • Jang, Min-Gyu;Choi, Jea-Young;Lee, Chul-Hee
    • Tribology and Lubricants
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    • v.26 no.3
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    • pp.184-189
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    • 2010
  • In this paper, tactile response characteristics in medical haptic interface are investigated to characterize the feeling of contact between the finger skin and the organic tissue when a finger is dragged over tissue. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, curvature and friction. Thus, the tactile display provides the surface information of organic tissue to the surgeon using different actuating mechanisms ranging from the conventional mechanical motor to the smart material actuators. In order to investigate the compliance feeling of human finger's touch, vertical force responses of the tactile display under the various magnetic fields have been assessed. Also, frictional resistive force responses of the tactile display are investigated to simulate the action of finger's dragging. From the results, different tactile feelings are observed as the applied magnetic field is varied and arrayed magnetic poles combinations. This research gives a smart technology of tactile displaying.

Torsional Vibration Damper Using Magneto-Rheological Fluid (MR 유체를 이용한 비틀림진동 감쇠기)

  • 안영공;신동춘;양보석;김동조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.313-317
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    • 2001
  • Magneto-Rheological fluid (MR fluid) is known as a class of functional fluid with controllable apparent viscosity of the fluid by the applied magnetic field strength. Extensive researches with the functional fluids have been done on applications of the fluid to mechanical components such as suspension, absorber, engine mount, clutch, break, valve, etc. In this study, a new torsional damper using MR fluid is proposed, and the response property of the damper was theoretically investigated. The present damper is quit effective for reducing the driveline vibration in a wide range of the engine speed.

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A Study on the Development of a Hydraulic Damper using Semi-Active Viscous Damping (반능동 점성감쇠를 이용한 유체댐퍼 개발에 관한 연구)

  • 전종균;김현식
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.1 no.2
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    • pp.15-20
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    • 2000
  • In this paper, hydraulic damper was studied to solve vibration problems of bridge, structures and several mechanic parts rising magnetic fluid. The damper was modeled using Magneto Rheological fluid and MR damper was manufactured on the basis of design drawing. To investigate the efficacy of magneto rheological phenomenon. experiments were performed on the several design parameters using Universal Testing Machine(UTM). Damping efficacy were examined by frequencies. displacement and electric currents through experiments.

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Design of Magneto-rheological Fluid Based Device (자기유변유체를 이용한 공학 장치의 설계)

  • Kim, Jeong-Hoon;Lee, Chong-Won;Jung, Byung-Bo;Park, Young-Jin;Cao, Guangzhong
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.544-549
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    • 2001
  • The effect of power supply voltage on the performance limits in a laboratory Magneto-rheological fluid based device was identified by experiments. It suggests that the frequency range of motion for control be limited by the voltage attenuation due to the coil inductance and the maximum power supply voltage set for practical use of MRF devices. In this work, the magnetic and electrical characteristics of MRF device are investigated and a design procedure is formulated to achieve the desired performance for a given power supply.

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Design of Magneto-Rheological Fluid Based Device

  • Kim, Jeong-Hun;Lee, Jong-Un;Jeong, Byeong-Bo;Park, Yong-Jin
    • Journal of Mechanical Science and Technology
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    • v.15 no.11
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    • pp.1517-1523
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    • 2001
  • The effect of power supply voltage on the performance limits in a laboratory magneto-rheological fluid based device was identified by experiments. It suggests that the frequency range of motion for control is limited by the voltage attenuation due to the coil inductance and the maximum power supply voltage set for practical use of an MRF devices. In this work, the magnetic and electrical characteristics of the MRF device are investigated and a design procedure is formulated to achieve the desired performance for a given power supply.

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