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