smart passive system based on mr damper

Smart Passive System Smart Passive System Based on MR DamperBased on MR Damper

JSSI 10JSSI 10thth Anniversary Symposium on Anniversary Symposium on Performance of Response Controlled BuildingsPerformance of Response Controlled BuildingsNov. 17-19 2004, Yokohama JapanNov. 17-19 2004, Yokohama Japan

Sang-Won Cho : Ph. D, KAIST Hyung-Jo Jung : Professor, Sejong UniversityJong-Heon Lee : Professor, Kyungil UniversityIn-Won Lee : Professor, KAIST

Sang-Won Cho : Ph. D, KAIST Hyung-Jo Jung : Professor, Sejong UniversityJong-Heon Lee : Professor, Kyungil UniversityIn-Won Lee : Professor, KAIST

2 2 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

CONTENTSCONTENTS

IntroductionIntroduction

Electromagnetic Induction System for Electromagnetic Induction System for MR DamperMR Damper

Numerical ExamplesNumerical Examples

ConclusionsConclusions

Further StudyFurther Study

3 3 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

BackgroundsBackgrounds

Introduction Introduction

• Semi-active control device has Semi-active control device has

reliability of passivereliability of passive and and adaptability of activeadaptability of active system. system.

• MR dampers are quite promising semi-active device forMR dampers are quite promising semi-active device for

small power requirementsmall power requirement, , reliabilityreliability, and , and inexpensiveinexpensive to to manufacture. manufacture.

4 4 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Without Magnetic Fields With Magnetic Fields

Bearing &

SealSolenoidAccumulator

MR FluidDiaphragm

Wires to

Electromgnet

Characteristics ofCharacteristics of Magnetorheological Magnetorheological ((MRMR)) fluidfluid and and damperdamper

5 5 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Installation of Conventional MR DamperInstallation of Conventional MR Damper

MR damper

• Requirement of eRequirement of external power, controller, sensorsxternal power, controller, sensors

• ComplicatComplication of ion of networknetworkss using many MR dampers using many MR dampersfor large-scale structurefor large-scale structure

• Difficulties to Difficulties to install install and maintainand maintain

6 6 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Objective and ScopeObjective and ScopeDevelopment of simple and Development of simple and effectiveeffective control device control device

• Consists of Consists of MR damperMR damper and and EMI system EMI system

• Changes kinetic energy of MR damper to electric energyChanges kinetic energy of MR damper to electric energy

7 7 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Schematic diagram

Electromagnetic Induction (EMI) System

EMI system

Line for external power source

MR fluidSolenoid

MR fluid Solenoid Permanent magnet

Conventional MR Damper

MR Damper with EMI System

8 8 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Mechanism

MR Damper

MR Damper

MR Damper

Permanent magnet

Solenoid

External power

Conventional MR Damper

MR Damper with EMI System

EMI system

9 9 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• Faraday’s law of induction

n : turns/m

B : magnetic flux

B : magnetic field

A : cross area

dt

dBAn

dt

dΦnε B (1)

Estimation of induced voltages by EMI system

10 10 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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)

560

21001320900

.

..

dt

dBAn

Length : 5cm

Area : 13.2cm2

2.55(V)

11 11 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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 examinat

ion of efficiency and applicability

Advantages of MR damper with EMI system

12 12 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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 examinat

ion of efficiency and applicability

Advantages of MR damper with EMI system

SMART

13 13 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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 examinat

ion of efficiency and applicability

Advantages of MR damper with EMI system

SMART

PASSIVE

14 14 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Three-story building (Dyke et al. 1996)

Numerical Example

MR damper

15 15 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

,

3.9800

03.980

003.98

kgM s

m

NC s

sec

50500

5010050

050175

m

NK s

84.684.60

84.67.1384.6

084.60.12

System data

16 16 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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 17 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

1 2 3 4 5 6 7 8 9 10

x 104

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1 2 3 4 5 6 7 8 9 10

x 104

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Variations of Sa Envelope of max. responses

Coil turns/m Coil turns/m

Sa

Hachinohe

Kobe

El Centro

1 2 3 4 5 6 7 8 9 10

x 104

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1 2 3 4 5 6 7 8 9 10

x 104

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Coil turns/m Coil turns/m

Si

Hachinohe

Kobe

El Centro

EMI-A : 2.6104

EMI-D : 2.2104

Max

. en

velo

pe o

f S

aM

ax. e

nve

lope

of

Si

18 18 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• 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

Analysis

19 19 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• Induced voltages for various earthquakes by EMI system

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-1

-0.5

0

0.5

1

1.5

2

2.5

3

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-1

-0.5

0

0.5

1

1.5

2

2.5

3

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-1

-0.5

0

0.5

1

1.5

2

2.5

3

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5-1

-0.5

0

0.5

1

1.5

2

2.5

3

Time (sec)

Vol

tage

(V

)V

olta

ge (

V)

Time (sec)

EL Centro

Kobe

Hachinohe

Northridge

Results

20 20 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• Normalized accelerations at each floor

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3

EL Centro

Kobe

Hachinohe

Northridge

Floor level

Nor

mal

ized

acc

el.

Nor

mal

ized

acc

el.

Floor level

Clipped-DClipped-AEMI-DEMI-A

21 21 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Nor

mal

ized

acc

el.

Nor

mal

ized

acc

el.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3

EL Centro

Kobe

Hachinohe

Northridge

Floor level Floor level

Clipped-DClipped-AEMI-DEMI-A

• Normalized interstory drifts at each floor

22 22 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• Normalized peak responses for various earthquakes

0 0.5 1 0 0.5 1

El Centro

Hachinohe

Kobe

Northridge

Peak Accel. Peak Drift

Clipped-D

Clipped-A

EMI-D

EMI-A

23 23 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

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

ConclusionsConclusions

24 24 Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

• Korea Patent 0416398

• Experimental tests

• Numerical modeling of EMI system using neural network

Further StudyFurther Study