• Title, Summary, Keyword: Magneto-rheological Fluid

Search Result 132, Processing Time 0.028 seconds

Design of Direct-Shear Mode MR Damper (전단 모드형 자성유체댐퍼의 설계)

  • Kim, Hae-Lan;Lee, Young-Shin;Lee, Eun-Yup;Lee, Gyu-Seop;Oh, Boo-Jin
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.626-631
    • /
    • 2007
  • MR(Magneto-rheological) fluid is smart material that can be changed viscosity by controlling the magnetic field. MR damper with MR fluid can control damping force. It can be used extensively many engineering structures for reducing the effect of dynamic external disturbances. There are three kinds of MR dampers, such as valve mode, direct-shear mode and squeeze mode. In this study, design process of direct-shear mode MR damper with the MR fluid gap was developed. The parameters that used in the direct-shear mode MR damper Informed from the experiment of valve mode MR damper of Lord company. Magnetic analysis with finite element method was performed to find the optimal annular gap.

  • PDF

Electromagnetic Design and Performance Evaluation of an MR valve (MR 밸브의 전자기적 설계와 성능 평가)

  • Kim, Ki-Han;Nam, Yun-Joo;Park, Myeong-Kwan
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.968-973
    • /
    • 2007
  • This paper presents an electromagnetic design for the magneto-rheological fluid valve. The MR valve can control high-level fluid power without moving parts, due to the apparent viscosity controllability of the MR fluid in magnetic fields. In order to improve the static characteristic of the MR valve, the length of the flux path is decreased by removing the unnecessary bulk of the yoke. Then, in order to improve the dynamic and hysteretic characteristics, the magnetic reluctance of the ferromagnetic material is increased by minimizing the cross sectional area through which the flux passes. Two MR valves, one is a conventional type valve and the other is the proposed one, were fabricated and performance evaluation is experimentally achieved through the comparison study using by-pass damper system.

  • PDF

Identification of Dynamic property of MR Fluid (MR 유체의 동특성)

  • Ahn, Young-Kong;Ha, Jong-Yong;Ahn, Kyoung-Kwan;Yang, Bo-Suk;Shiraishi, Toshihiko;Morishita, Shin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.576-579
    • /
    • 2005
  • MR (Magneto Rheological) fluids are well known as a smart fluid and their application researches to control vibration have been conducted by many researchers. However, their dynamic properties have not been identified clearly yet. Therefore, the MR effect is investigated by using a rotational viscometer and a single degree of freedom system with an MR damper. The results obtained from the experimental study show that stiffness and viscous damping coefficients of the system with an MR damper are changed according to the variation of the applied current.

  • PDF

Wind-Induced Vibration Control of a Tall Building Using Magneto-Rheological Dampers: A Feasibility Study

  • Gu, Ja-In;Kim, Saang-Bum;Yun, Chung-Bang;Kim, Yun-Seok
    • Computational Structural Engineering : An International Journal
    • /
    • v.3 no.1
    • /
    • pp.61-68
    • /
    • 2003
  • A recently developed semi-active control system employing magneto-rheological (MR) fluid dampers is applied to vibration control of a wind excited tall building. The semi-active control system with MR fluid dampers appears to have the reliability of passive control devices and the adaptability of fully active control systems. The system requires only small power source, which is critical during severe events, when the main power source may fail. Numerical simulation studies are performed to demonstrate the efficiency of the MR dampers on the third ASCE benchmark problem. Multiple MR dampers are assumed to be installed in the 76-story building. Genetic algorithm is applied to determine the optimal locations and capacities of the MR dampers. Clipped optimal controller is designed to control the MR dampers based on the acceleration feedback. To verify the robustness with respect to the variation of the external wind force, several cases with different wind forces are considered in the numerical simulation. Simulation results show that the semi-actively controlled MR dampers can effectively reduce both the peak and RMS responses the tall building under various wind force conditions. The control performance of the MR dampers for wind is found to be fairly similar to the performance of an active tuned mass damper.

  • PDF

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
    • /
    • v.26 no.3
    • /
    • pp.184-189
    • /
    • 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.

Dynamic Properties of Squeeze Type Mount Using MR Fluid (MR유체를 이용한 스퀴즈모드형 마운트의 동특성)

  • 하종용;안영공;양보석;정석권;김동조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.374-378
    • /
    • 2003
  • This paper presents investigation of damping characteristics of squeeze mode type MR (Magneto-Rheological) mount experimentally. Since damping property of the MR fluid is changed by variation of the applied magnetic field strength, squeeze mode type MR mount proposed in the study has variable damping characteristics according to the applied magnetic field s strength. In the present work, the performance of the mount was experimentally investigated according to the magnetic field strength and exciting frequencies. 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 and MR effect is reduced by increasing exciting frequency.

  • PDF

Dynamic Properties of Squeeze Type Mount Using MR Fluid (MR유체를 이용한 스퀴즈모드 타입 마운트의 동특성)

  • Ahn, Young-Kong;Yang, Bo-Suk;Ha, Jong-Yong;Kim, Dong-Jo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.464-467
    • /
    • 2002
  • This paper presents investigation of damping characteristics of squeeze mode type MR (magneto-Rheological) mount experimentally. Since damping property of the MR fluid is changed by variation of the applied magnetic field strength, squeeze mode type MR mount proposed in the study has variable damping characteristics according to the applied magnetic field strength. Impact and excitation tests were performed to investigate the dynamic properties of squeeze mode type MR mount. Responses of the mount were compared in proportion to the applied magnetic field strength. The experimental results show that the mount can effectively reduce vibration amplitude in a wide frequency range by changing the applied magnetic field strength.

  • PDF

Dynamic Properties of Squeeze Type Mount Using MR Fluid (MR 유체를 이용한 스퀴즈모드형 마운트의 동특성)

  • 안영공
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.13 no.6
    • /
    • pp.490-495
    • /
    • 2003
  • This paper presents investigation of damping characteristics of squeeze mode type MR (magneto-rheological) mount experimentally. Since damping property of the MR fluid is changed by variation of the applied magnetic field strength, squeeze mode type MR mount proposed in the study has variable damping characteristics according to the applied magnetic field strength. In the present work, the performance of the mount was experimentally Investigated according to the magnetic field strength and exciting frequencies. The experimental results present that the MR mount can effectively reduce the vibration in a wide range of frequency by controlling the applied electromagnetic field 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 and MR effect is reduced by increasing exciting frequency.

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
    • /
    • /
    • pp.111-112
    • /
    • 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.

  • PDF