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Smart Passive System Based on MR Damper

JSSI 10 th Anniversary Symposium on Performance of Response Controlled Buildings Nov. 17-19 2004, Yokohama Japan. Smart Passive System Based on MR Damper. Sang-Won Cho : Ph. D, KAIST Hyung-Jo Jung : Professor, Sejong University Jong-Heon Lee : Professor, Kyungil University

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Smart Passive System Based on MR Damper

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  1. JSSI 10th Anniversary Symposium on Performance of Response Controlled Buildings Nov. 17-19 2004, Yokohama Japan Smart Passive System Based on MR Damper Sang-Won Cho : Ph. D, KAIST Hyung-Jo Jung : Professor, Sejong University Jong-Heon Lee : Professor, Kyungil University In-Won Lee : Professor, KAIST

  2. CONTENTS • Introduction • Electromagnetic Induction System for MR Damper • Numerical Examples • Conclusions • Further Study

  3. Introduction • Backgrounds • Semi-active control device has reliability of passive and adaptability of active system. • MR dampers are quite promising semi-active device for small power requirement, reliability, and inexpensive to manufacture.

  4. Characteristics of Magnetorheological(MR)fluid and damper With Magnetic Fields Without Magnetic Fields Wires to Electromgnet Diaphragm MR Fluid Bearing & Seal Accumulator Solenoid

  5. Installation of Conventional MR Damper MR damper • Requirement of external power, controller, sensors • Complication of networks using many MR dampers for large-scale structure • Difficulties to install and maintain

  6. Objective and Scope Development of simple and effective control device • Consists of MR damper and EMI system • Changes kinetic energy of MR damper to electric energy

  7. Electromagnetic Induction (EMI) System • Schematic diagram Conventional MR Damper MR fluid Line for external power source Solenoid MR Damper with EMI System MR fluid Solenoid Permanent magnet EMI system

  8. Mechanism Conventional MR Damper MR Damper External power Permanent magnet MR Damper with EMI System MR Damper Solenoid MR Damper EMI system

  9. Estimation of induced voltages by EMI system • Faraday’s law of induction • n : turns/m • B : magnetic flux • B : magnetic field • A : cross area (1)

  10. If we assume as below - Magnetic field : 1.2 T (Tesla) - Turns of solenoid : 900 turns/m - Area of cross section : 13.2 (cm2) - Velocity of stroke : 9 cm/s (max. value of uncontrolled) Area : 13.2cm2 Length : 5cm

  11. Advantages of MR damper with EMI system • Adaptability : damping varies with • strength of external loads • Simplicity : No power, no controller, and • no sensors • Thus, • we propose smart passive system based-on MR damper • Efficiency : ?? • EMI system will be applied to numerical example for examination of efficiency and applicability

  12. Advantages of MR damper with EMI system • Adaptability : damping varies with • strength of external loads • Simplicity : No power, no controller, and • no sensors • Thus, • we propose smart passive system based-on MR damper • Efficiency : ?? • EMI system will be applied to numerical example for examination of efficiency and applicability SMART

  13. Advantages of MR damper with EMI system • Adaptability : damping varies with • strength of external loads • Simplicity : No power, no controller, and • no sensors • Thus, • we propose smart passive system based-on MR damper • Efficiency : ?? • EMI system will be applied to numerical example for examination of efficiency and applicability SMART PASSIVE

  14. Numerical Example • Three-story building (Dyke et al. 1996) MR damper

  15. System data

  16. Determination of coil turns for solenoid By varying two parameters, Sa and Si Sa : summation of peak acceleration at each floor Si : summation of peak interstory drift at each floor which are normalized by uncontrolled responses Using envelope of maximum value of Sa and Si for El Centro, Hachinohe, Kobe earthquakes Two EMI systems are designed: EMI-A from Sa and EMI-D from Si • Design of EMI system

  17. El Centro El Centro Kobe Kobe Hachinohe Hachinohe Max. envelope of Sa Sa EMI-A : 2.6104 Coil turns/m Coil turns/m Variations of Sa Envelope of max. responses Max. envelope of Si Si EMI-D : 2.2104 Coil turns/m Coil turns/m

  18. Analysis • Comparisons • Proposed EMI systems : EMI-A, EMI-D • Conventional MR damper : Clipped-A, Clipped-D （using clipped-optimal controller) • Performances • Normalized acceleration and drift at each floor • El Centro, Hachinhe, Kobe, Northridge earthquakes

  19. Results Induced voltages for various earthquakes by EMI system EL Centro Hachinohe Voltage (V) Kobe Northridge Voltage (V) Time (sec) Time (sec)

  20. Normalized accelerations at each floor EL Centro Hachinohe Normalized accel. Clipped-D Clipped-A EMI-D EMI-A Kobe Northridge Normalized accel. Floor level Floor level

  21. Normalized interstory drifts at each floor EL Centro Hachinohe Normalized accel. Clipped-D Clipped-A EMI-D EMI-A Kobe Northridge Normalized accel. Floor level Floor level

  22. Normalized peak responses for various earthquakes Clipped-D Clipped-A EMI-D EMI-A El Centro Hachinohe Kobe Northridge Peak Accel. Peak Drift

  23. Smart Passive System Developed Consists of MR damper and EMI system Adaptable to external loads Simple structure without power, controller, sensors Shows comparable performances to clipped optimal controller • Conclusions

  24. Korea Patent 0416398 Experimental tests Numerical modeling of EMI system using neural network • Further Study

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