Hyung-Jo Jung Hyung-Jo Jung Sejong University, Korea Sejong University, Korea Kang-Min Choi Kang-Min Choi Korea Advanced Inst. Korea Advanced Inst. of Science and Tech. of Science and Tech. Sang-Won Cho Sang-Won Cho Korea Advanced Inst. Korea Advanced Inst. of Science and Tech. of Science and Tech. In-Won Lee In-Won Lee University of Western University of Western Ontario, Canada 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 Electromagnetic Induction Part Part World Conference on Structural Control and Monitoring (4WCSC World Conference on Structural Control and Monitoring (4WCSC
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Hyung-Jo Jung Sejong University, Korea Hyung-Jo Jung Sejong University, Korea Kang-Min Choi Korea Advanced Inst. of Science and Tech. Kang-Min Choi Korea.
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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)
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
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
INTRODUCTION INTRODUCTION
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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.
INTRODUCTION INTRODUCTION
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.
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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.
INTRODUCTION INTRODUCTION
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
Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM
EMI system
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
SMARTSMART
Advantages of Advantages of Proposed Control SystemProposed Control System
Adaptability : damping characteristics of MR damper vary with
strength of external load
Simplicity : no power source, no controller, and no sensors
PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
PASSIVEPASSIVE
Advantages of ProposedAdvantages of Proposed Control System Control System
Adaptability : damping characteristics of MR damper vary with
strength of external load
Simplicity : no power source, no controller, and no sensors
SMARTSMART
PROPOSED CONTROL SYSTEMPROPOSED CONTROL SYSTEM
NUMERICALNUMERICAL V VERFICATIONERFICATION
Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
NUMERICALNUMERICAL V VERFICATIONERFICATION
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
NUMERICALNUMERICAL V VERFICATIONERFICATION
Simulation Results
Three-story Three-story BBuilding uilding Model Installed EMI SystemModel Installed EMI System
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
Dynamics and Smart Structures Lab., Sejong Univ., KOREA
Thank You for Your Attention!Thank You for Your Attention!
Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
NUMERICALNUMERICAL V VERFICATIONERFICATION
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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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Dynamics and Smart Structures Lab., Sejong Univ., 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
NUMERICALNUMERICAL V VERFICATIONERFICATION
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
NUMERICALNUMERICAL V VERFICATIONERFICATION
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Dynamics and Smart Structures Lab., Sejong Univ., KOREA
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
NUMERICALNUMERICAL V VERFICATIONERFICATION
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Dynamics and Smart Structures Lab., Sejong Univ., 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 floorNormalized interstory drifts at each floor