Hyung-Jo Jung Sejong University, Korea Hyung-Jo Jung Sejong University, Korea Kang-Min Choi Korea...

Hyung-Jo JungHyung-Jo Jung Sejong University, KoreaSejong University, Korea

Kang-Min Choi Kang-Min Choi Korea Advanced Inst. of Science and Tech.Korea Advanced Inst. of Science and Tech.

Sang-Won Cho Sang-Won Cho Korea Advanced Inst. of Science and Tech.Korea Advanced Inst. of Science and Tech.

In-Won Lee In-Won Lee University of Western Ontario, CanadaUniversity of Western Ontario, Canada

University of San Diego, July 11-13, 2006

An MR Damper-based Control An MR Damper-based Control System Introducing System Introducing

Electromagnetic Induction PartElectromagnetic Induction Part

Fourth World Conference on Structural Control and Monitoring (4WCSCM)Fourth World Conference on Structural Control and Monitoring (4WCSCM)

OUTLINEOUTLINE

IntroductionIntroduction

Proposed Control SystemProposed Control System

Numerical VerificationNumerical Verification

Experimental VerificationExperimental Verification

ConclusionsConclusionsDynamics and Smart Structures Lab., Sejong Univ., KOREA

BackgroundBackground

INTRODUCTION INTRODUCTION

Smart damping systemsSmart damping systems (i.e., semiactive control systems): (i.e., semiactive control systems):

- - reliabilityreliability of passive systems; of passive systems; adaptabilityadaptability of active systems of active systems

- smart damping devices: variable stiffness damper, variable - smart damping devices: variable stiffness damper, variable friction damper, MR/ER damper, etc.friction damper, MR/ER damper, etc.

An MR damper-based control systemAn MR damper-based control system is one of the promisin is one of the promising smart damping systems, because of its mechanical simplicitg smart damping systems, because of its mechanical simplicity, high dynamic range, low operating power requirements, eny, high dynamic range, low operating power requirements, environmental robustness, and so on. vironmental robustness, and so on.

Dynamics and Smart Structures Lab., Sejong Univ., KOREA

4


Conventional MR Damper-based SystemConventional MR Damper-based System

MR damper

A control system including A control system including sensors, a controller and an esensors, a controller and an extxternal power sourceernal power source

Difficult to Difficult to install install and maintain the conventional system, and maintain the conventional system, especially in the cases of large-scale structures such as hiespecially in the cases of large-scale structures such as high-rise buildings and long-span bridgesgh-rise buildings and long-span bridges


5


Possible SolutionsPossible Solutions Application of advanced technologies such as Application of advanced technologies such as power power

harvestingharvesting and and wireless sensor networkswireless sensor networks

Development of Development of passivelypassively operated control systems operated control systems with with adaptabilityadaptability and and high performancehigh performance

Etc.Etc.


One of the promising systems is the smart passive coOne of the promising systems is the smart passive control system proposed by Cho ntrol system proposed by Cho et alet al. (2005).. (2005).

* S.W. Cho, * S.W. Cho, H.J. JungH.J. Jung, and I.W. Lee, “Smart passive system based on mag, and I.W. Lee, “Smart passive system based on magnetorheological damper,” netorheological damper,” Smart Mater. StructSmart Mater. Struct., 14, 707-714, 2005.., 14, 707-714, 2005.

6


ObjectivesObjectives

To introduce a newly developed MR damper-To introduce a newly developed MR damper-based control system.based control system.

To numerically and experimentally verify the To numerically and experimentally verify the

effectiveness of the proposed control effectiveness of the proposed control

system for seismic protection of building system for seismic protection of building

structures.structures.


Conventional MR Damper-based Control SystemConventional MR Damper-based Control System

MR Damper

controller

power source

command

current

PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM

Control System

sensor


8


An EMI system consists of permanent magnet and coils.

It changes the kinetic energy of the reciprocation motion of the MR damper to the electric energy according to the Faraday’s law of induction.

Proposed MR Damper-based Control System Proposed MR Damper-based Control System MR damper with Electromagnetic induction (EMI) systemMR damper with Electromagnetic induction (EMI) system

MR Damper

damper deformation

magnetic field

inducedcurrent


EMI system

9


Proposed MR Damper-based Control SystemProposed MR Damper-based Control System MR damper with Electromagnetic induction (EMI) systemMR damper with Electromagnetic induction (EMI) system

Conventional System

Control systemControl system including including

sensors, controller, and sensors, controller, and

power supplypower supply

EMI systemEMI system consisting consisting of permanent magnet of permanent magnet

and coilsand coils

Proposed System


10


Adaptability : damping characteristics of MR damper vary with

strength of external load

Simplicity : no power source, no controller, and no sensors

Advantages of Advantages of Proposed Control SystemProposed Control System


11


SMARTSMART

Advantages of Advantages of Proposed Control SystemProposed Control System





12


PASSIVEPASSIVE

Advantages of ProposedAdvantages of Proposed Control System Control System




SMARTSMART


NUMERICALNUMERICAL V VERFICATIONERFICATION


kgM s

39800

03980

00398

.

.

.

m

NC s

sec

50500

5010050

050175

m

NK s

84.684.60

84.67.1384.6

084.60.12

Three-story Building (Dyke et al. 1996)

MR damper

14


Proposed MR damper-based control system

- SPC-D: EMI part designed to reduce drifts

- SPC-A: EMI part designed to reduce accelerations

Conventional smart damping system

- CO-D: clipped-optimal algorithm to reduce drifts

- CO-A: clipped-optimal algorithm to reduce accelerations

Control Systems Compared


15


Normalized peak responses under four historic earthquakes Normalized peak responses under four historic earthquakes

0 0.5 1 0 0.5 1

El Centro

Hachinohe

Kobe

Northridge

Peak Accel. Peak Drift

CO-D

CO-A

SPC-D

SPC-A


Simulation Results

Three-story Three-story BBuilding uilding Model Installed EMI SystemModel Installed EMI System

EXPERIMENTAL VERIFICATIONEXPERIMENTAL VERIFICATION


17


-0.2

-0.1

0

0.1

0.2

0 5 10 15 20 25 30

Time (sec)

Acceleration (g)

GGround Input Motion round Input Motion (Scaled El Centro Earthquake)(Scaled El Centro Earthquake)


- 진동대 입력 하중 : • 40% El Centro earthquake (PGA: 0.1395 g) • 20% El Centro earthquake (PGA: 0.0697 g) • 30% Hachinohe earthquake (PGA: 0.0811 g) • 20% Kobe earthquake (PGA: 0.1643 g) • 10% Northridge earthquake (PGA: 0.0843 g)

• 40% El Centro earthquake (PGA: 0.1395 g) • 20% El Centro earthquake (PGA: 0.0697 g) • 30% Hachinohe earthquake (PGA: 0.0811 g) • 20% Kobe earthquake (PGA: 0.1643 g) • 10% Northridge earthquake (PGA: 0.0843 g)

18



Experimental Results: Movie ClipsExperimental Results: Movie Clips

19


0.4

0.6

0.8

0 1 2 3 4 5 6 7 8 9 10Voltage (V)

Norm

alized v

alu

e


0.0

0.2

0.4

0.6

0.8

1.0

0 1 2 3 4 5 6 7 8 9 10Voltage (V)

Nor

mal

ized

val

ue

Experimental Results: Passive-mode CaseExperimental Results: Passive-mode Case

Peak Acceleration at 3rd floor Peak Drift between 2nd and 3rd floors

Passive-off: 0 VoltPassive-off: 0 Volt Passive-optimal: 3 VoltPassive-optimal: 3 Volt Passive-on: 10 VoltPassive-on: 10 Volt

20


0.00

0.20

0.40

0.60

0.80

1.00

0.5 1 1.5 2

Passive voltage value (V)

Nor

mal

ized

val

ue

d₁ d₂

a₁ a₃

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

0.5 1 1.5 2

Passive voltage value (V)N

orm

aliz

ed v

alue

.

Optimal


21


Experimental Results: Acceleration at 3Experimental Results: Acceleration at 3rdrd Floor Floor


Acceleration

-4

-3

-2

-1

0

1

2

3

4

0 5 10 15 20 25 30

Time (sec)

Acc

eler

ation

(m/s

ec2)

Passive-on (10Volt)

Smart passive

22


0

0.3

0.6

0.9

1.2

1.5

1.8

0 5 10 15 20 25

-30

-20

-10

0

10

20

30

0 5 10 15 20 25

UncontrolledSmart passive control

-6

-4

-2

0

2

4

6

0 5 10 15 20 25

UncontrolledSmart passive control


23



Experimental Results: ComparisonExperimental Results: Comparison

Peak Acceleration at 3rd floor Peak Drift between 2nd and 3rd floors

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Proposed MR Damper-basedProposed MR Damper-based Control System Control System

• Compact, simple, and cost-effective.Compact, simple, and cost-effective.

• Adaptable to external loadsAdaptable to external loads..

• Shows the comparable performance to a conventional smart Shows the comparable performance to a conventional smart system using clipped optimal algorithm in numerical simulasystem using clipped optimal algorithm in numerical simulation.tion.

• Shows the comparable performance to optimal passive case Shows the comparable performance to optimal passive case in preliminary experiment.in preliminary experiment.

CONCLUSIONSCONCLUSIONS


Thank You for Your Attention!Thank You for Your Attention!


27


Determination of coil turns for solenoidDetermination of coil turns for solenoid

By varying two parameters, By varying two parameters, SSaa and and SSii

SSaa : summation of peak acceleration at each floor: summation of peak acceleration at each floor

SSii : summation of peak interstory drift at each floor: summation of peak interstory drift at each floor

which are normalized by uncontrolled responseswhich are normalized by uncontrolled responses

Using envelope of maximum value of Using envelope of maximum value of SSaa and and SSii

for El Centro, Hachinohe, Kobe earthquakes for El Centro, Hachinohe, Kobe earthquakes

Two EMI systems are designed:Two EMI systems are designed:

EMI-A from EMI-A from SSaa and EMI-D from and EMI-D from SSii

Design of EMI System


28


Faraday’s law of induction

: induced electromotive force from EMI system n : number of turns of coil

B : magnetic flux

B : magnetic field

A : cross area

w : width of the area covered by magnetic field

x : damper deformation

dt

d

dt

d

dt

dΦB xwBn

ABnnε (1)

Estimation of induced voltages by EMI system

SMART PASSIVE CONTROL SYSTEMSMART PASSIVE CONTROL SYSTEM

29


dt

dwB

dt

dAB

x nn

dt

dΦn B

dt

dxKemf

wB nemfK

where :damper deformation

: width of area covered by magnetic field

x

(15)

(16)

(17)

w

EMI systemEMI systemSMART PASSIVE CONTROL SYSTEMSMART PASSIVE CONTROL SYSTEM

30


If we assume as belowIf we assume as below- Magnetic field- Magnetic field : 1.2 T (Tesla): 1.2 T (Tesla)

- Turns of solenoid - Turns of solenoid : 900 turns/m: 900 turns/m

- Area of cross section- Area of cross section : 13.2 (: 13.2 (cmcm22))

- Velocity of stroke- Velocity of stroke : 9 : 9 cmcm//s s (max. value of (max. value of

uncontrolled)uncontrolled)

560

21001320900

.

..

dt

dBAn

Length : 5cm

Area : 13.2cm2

2.55(V)

SMART PASSIVE CONTROL SYSTEMSMART PASSIVE CONTROL SYSTEM

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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


32


Induced voltages for various earthquakes by EMI systemInduced 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


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Normalized accelerations at each floorNormalized 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


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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 floorNormalized interstory drifts at each floor


Hyung-Jo Jung Sejong University, Korea Hyung-Jo Jung Sejong University, Korea Kang-Min Choi Korea...

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