1. MR 댐퍼를 기반으로 하는 스마트 수동제어 시스템 대한토목학회 정기 학술대회 2004 년 10 월 21 일 조상원 : KAIST 건설환경공학과, 박사 이헌재 : KAIST 건설환경공학과, 박사과정 오주원 : 한남대학교 토목환경공학과, 교수 이인원 : KAIST 건설환경공학과, 교수 조상원 : KAIST 건설환경공학과, 박사 이헌재 : KAIST 건설환경공학과, 박사과정 오주원 : 한남대학교 토목환경공학과, 교수 이인원 : KAIST 건설환경공학과, 교수

2. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 1 CONTENTS Introduction Introduction Electromagnetic Induction System for Electromagnetic Induction System for MR Damper MR Damper Numerical Examples Numerical Examples Conclusions Conclusions Further Study Further Study

3. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 2 Backgrounds Backgrounds Introduction Introduction Semi-active control device hasSemi-active control device has reliability of passive and adaptability of active system. MR dampers are quite promising semi-active device forMR dampers are quite promising semi-active device for small power requirement, reliability, and inexpensive to manufacture.

4. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 3 Without Magnetic Fields With Magnetic Fields Bearing & Seal Coil Accumulator MR Fluid Diaphragm Wires to Electromgnet Characteristics of MR damper Characteristics of MR damper

5. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 4 Installation of Conventional MR Damper Installation of Conventional MR Damper MR damper External power source, controller, sensorsExternal power source, controller, sensors Complicated network using many MR dampersComplicated network using many MR dampers Difficulties to set up and maintainDifficulties to set up and maintain

6. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 5 Objective and Scope Objective and Scope Development of simple and effective control device Consists of permanent magnets and solenoidConsists of permanent magnets and solenoid Changes kinetic energy of MR damper to electric energyChanges kinetic energy of MR damper to electric energy

7. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 6 Schematic diagram Electromagnetic Induction (EMI) System EMI system Line for external power source MR fluid Solenoid MR fluid Solenoid Permanent magnet Conventional MR Damper MR Damper with EMI System

8. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 7 Mechanism MR Damper Permanent magnet Solenoid External power Conventional MR Damper MR Damper with EMI System

9. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 8 Faraday’s law of induction n: turns/m  B : magnetic flux B: magnetic field A: cross area (1) Estimation of induced voltages by EMI system

10. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 9 If we assume as below - Magnetic field: 1.2 T (Tesla) - Turns of solenoid : 900 turns/m - Area of cross section: 13.2 (cm 2 ) - Velocity of stroke: 9 cm/s (max. value of uncontrolled) This EMI system will be applied to numerical example for examination of applicability Length : 5cm Area : 13.2cm 2

11. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 10 MR Damper Numerical Example Three-story building (Dyke et al. 1996)

12. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 11 System data

13. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 12 Determination of coil turns for solenoid By varying two parameters, S a and S i S a : summation of peak acceleration at each floor S i : summation of peak interstory drift at each floor which are normalized by uncontrolled responses Using envelope of maximum value of S a and S i for El Centro, Hachinohe, Kobe earthquakes Two EMI systems are designed: EMI-A from S a and EMI-D from S i Design of EMI system

14. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 13 Variations of S a Envelope of max. responses Coil turns/m SaSa Hachinohe Kobe El Centro Coil turns/m SiSi Hachinohe Kobe El Centro EMI-A : 2.6  10 4 EMI-D : 2.2  10 4 Max. envelope of S a Max. envelope of S i

15. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 14 Comparisons – Proposed EMI systems : EMI-A, EMI-D – Previous clipped optimal controllers : Clipped-A, Clipped-D Performances – Normalized acceleration and drift at each floor – El Centro, Hachinhe, Kobe, Northridge earthquakes Analysis

16. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 15 Induced voltages for various earthquakes by EMI system Time (sec) Voltage (V) Time (sec) EL Centro Kobe Hachinohe Northridge ResultsAnalysis

17. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 16 Normalized accelerations at each floor EL Centro Kobe Hachinohe Northridge Floor level Normalized accel. Floor level Clipped-D Clipped-A EMI-D EMI-A

18. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 17 Normalized accel. EL Centro Kobe Hachinohe Northridge Floor level Clipped-D Clipped-A EMI-D EMI-A Normalized interstory drifts at each floor

19. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 18 Normalized peak responses for various earthquakes El Centro Hachinohe Kobe Northridge Peak Accel.Peak Drift Clipped-D Clipped-A EMI-D EMI-A

20. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 19 EMI system Developed for MR damper-based control system Consists of permanent magnet and solenoid Simple structure without power, controller, sensors Shows comparable performances to clipped optimal controller Conclusions Conclusions

21. Structural Dynamics & Vibration Control Lab., KAIST, Korea Structural Dynamics & Vibration Control Lab., KAIST, Korea 20 특허등록 : 등록번호 0416398 Experimental tests Numerical modeling of EMI system using neural network Further Study Further Study