장지은 , 한국과학기술원 건설 및 환경공학과 석사과정 정형조 ,...

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

장지은 , 한국과학기술원 건설 및 환경공학과 석사과정정형조 , 세종대학교 토목환경공학과 조교수정 운 , 현대건설기술개발원 주임연구원이인원 , 한국과학기술원 건설 및 환경공학과 교수

MR 유체 감쇠기를 이용한 사장 케이블 제진 시스템의 실험적 검증

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

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

33Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Cable Damping Experimental Setup

Schematic of smart cable damping experiment

shaker flat-sagcable

spectrumanalyzer

MR dampers

digital controller

)(tFd

)(tFs

dw

u

ew

44Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Cable

Real-scaled cable at HICT

parameters valuesL 44.7 m

m 89.86 N/m

T 500 KN

1.34 m13.4 m

8.372.53 Hz

dx

0005.00015.0

2

1

i

0

sx

55Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

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

Cable model

66Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

MR damper

• MR controllable friction damper (RD-1097-01 from Lord Corporation)• Maximum force level: 100 N• Maximum voltage: 1.4 V• Location : 1.34m from bottom support

77Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Cable exciting system (Kim et al. 2002)

temtF sin)( force exciting Harmonic 2

mass exciting : frequency exciting : where

m

(1)

88Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

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.

99Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Control algorithms: to calculate the command voltage input

• Passive-mode cases

• Semiactive control cases (Jansen and Dyke 2000)

- Clipped-optimal control algorithm - Control based on Lyapunov stability theory - Maximum energy dissipation algorithm - Modulated homogeneous friction algorithm

1010Structural 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

)

1111Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Damping ratios in the passive-mode cases by Hilbert transform-based identification method

Dam

ping

rat

io

(%)

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

1212Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea

Damping ratios in the semiactive control cases by Hilbert transform-based identification method

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

1313Structural 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.

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 control based on Lyapunov stability and the clipped- optimal control show slightly better performance than the passive-on case.