케이블 진동 감쇠를 위한 반능동 제어 장치 성능의 실험적 평가
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Transcript of 케이블 진동 감쇠를 위한 반능동 제어 장치 성능의 실험적 평가
케이블 진동 감쇠를 위한
반능동 제어 장치 성능의 실험적 평가
케이블 진동 감쇠를 위한
반능동 제어 장치 성능의 실험적 평가
2004 년도 한국전산구조공학회 추계 학술발표회목포해양대학교 2004 년 10 월 9 일
장지은 , 한국과학기술원 건설 및 환경공학과 석사과정정형조 , 세종대학교 토목환경공학과 조교수정 운 , 현대건설기술개발원 주임연구원이인원 , 한국과학기술원 건설 및 환경공학과 교수
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Introduction
Cable Damping Experimental Setup
Experimental Results
Conclusions
Contents
33Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Introduction
Cable
• Cables are efficient structural elements that are used in cable-stayed bridges, suspension bridges and other cable structures.
• Steel cables are flexible and have low inherent damping, resulting in high susceptibility to vibration.
• Vibration can result in premature cable or connection
failure and/or breakdown of the cable corrosion protection
systems, reducing the life of the cable structure.
• Numerous passive and active cable damping studies have been performed and full-scale applications realized.
44Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Semiactive damping system
- Johnson et al. (1999, 2000): verification of the efficacy of
a semiactive damper for a taut/sagged cable model
- Christenson (2001): experimental verification of the
performance of an MR damper in mitigating cable
responses by using a medium-scale cable
- Ni et al. (2002), Ko et al. (2002), Duan et al. (2002): field
comparative tests of cable vibration control using
MR dampers (the world’s first time implementation
of MR-based smart damping technology in civil
engineering structures)
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Objectives
• To experimentally verify the performance of the MR
damper-based control systems for suppressing vibration of
real-scaled stay cables using various semiactive control
algorithms
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Cable Damping Experimental Setup
Schematic of smart cable damping experiment
Where, )(tFs
: displacement at damper location
: shaker force
)(tFd : damper force
: evaluation displacement
shakershaker flat-sagcable
flat-sagcable
spectrumanalyzer
spectrumanalyzer
MR dampers
MR dampers
digital controller
digital controller
)(tFd
)(tFs
dw
dw
u
u
ew
ew: control signal
77Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Cable
Real-scaled cable at HICT
parameters values
L 44.7 m
m 89.86 N/m
T 500 KN
1.34 m
13.4 m
8.37
2.53 Hz
dx
0005.0
0015.0
2
1
i
0
sx
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Cable model
• Transverse motion of cable could be modeled by
the motion of a taut string because of small sag
(0.1% sag-to-span ratio with tension of 500 kN).
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dx sx
),( txvx
where ),( txv
)(tFd dxx : transverse deflection of the cable
: transverse damper force at location
)(tFd )(tFs
)(tFs sxx
L
: transverse shaker force at location
: angle of inclination
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MR damper
• MR controllable friction damper
(RD-1097-01 from Lord Corporation)
• Maximum force level: 100 N
• Maximum voltage: 1.4 V
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MR damper installation
• Twin damper setup
• Location : 1.34m
from bottom support
• Measurement : Damper force,
displacement, and
acceleration
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Cable exciting system (Kim et al. 2002)
temtF sin)( force exciting Harmonic 2
mass exciting :
frequency exciting : where
m
(1)
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Controller
• The controller is constructed by the Matlab Real-Time
Workshop executed in real time using MS Visual C++.
• The measured responses are acquired from displacement
and acceleration sensors at damper location and converted into digital data by NI DAQ Card-6062E.
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Control algorithms:
to calculate the command voltage input
• Passive-mode cases
- passive-off (v=0V),
- passive-on (v= 1.4V)
- other passive-modes (v= 0.6V, 1.0V, 1.1V, 1.2V, 1.3V)
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• Semiactive control cases (Jansen and Dyke 2000)
- Clipped-optimal control algorithm
where, Vmax=1.4V, Fd ci= the desired control force, and
Fd = the measured control force
- Control based on Lyapunov stability theory
where, z = the state vector, and
P = the matrix to be found using the Lyapunov equation
)}({max ddcidi FFFHVv
))((max dT
i PBFzHVv
(2)
(3)
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- Maximum energy dissipation algorithm
where, vd = the velocity at the damper location
- Modulated homogeneous friction algorithm
)(max ddi FvHVv
|)|(max ddi FFHVvn
)(tiPgF ndn
P[i(t)] = i(t-s),
where s = {min x0: i(t-x)=0}
(4)
(5)
1717Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Experimental Results
Displacement in free vibration
Time (sec)
Dis
plac
emen
t (m
)
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Damping ratios for verification of performances
• The amplitude-dependent damping ratios are calculated by
the Hilbert transform-based identification method
(Duan et al. 2002)
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Damping ratios in the passive-mode casesD
ampi
ng r
atio
(%
)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 5 10 15 20 25
passive V=1.4 passive V=1.3 passive V=1.2passive V=1.1passive V=1.0passive V=0.6passive V=0.0uncontrolled
Amplitude (mm) at the location of 10.2 m away from the bottom support
2020Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Damping ratios in the semiactive control cases
Amplitude (mm) at the location of 10.2 m away from the bottom support
Dam
ping
rat
io
(%)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
3 5 7 9 11 13 15 17
Passive offPassive onClipped optimalLyapunovMHFMEDA
2121Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea
Conclusions
Semiactive control systems significantly improve the
mitigation of stay cable vibration over the uncontrolled
and the passive-off cases.
Semiactive control systems significantly improve the
mitigation of stay cable vibration over the uncontrolled
and the passive-off cases.
The Modulated homogeneous friction algorithm shows
nearly the same performance as the passive-on case.
The Modulated homogeneous friction algorithm shows
nearly the same performance as the passive-on case.
The performance of MR damper-based control systems for suppressing vibration of stay cables is experimentally verified.
The performance of MR damper-based control systems for suppressing vibration of stay cables is experimentally verified.
The control based on Lyapunov stability and the clipped-
optimal control show slightly better performance than
the passive-on case.
The control based on Lyapunov stability and the clipped-
optimal control show slightly better performance than
the passive-on case.