Damping Identification of Cable Vibration with and without MR Dampers

Damping Identification of Cable Vibration with and without MR Dampers

Vibrations of stay cable under specific loading, such as wind loading and heavy rainfall, always induced large vibration amplitude which may lead to first passage failure or fatigue failure of cable. Therefore, vibration control using passive or semi-active control devices had been used. The objective of this study is to investigate the dynamic characteristics of stayed cable with and without dampers from laboratory experiments. First, the relationship between the cable tensile force and vibration frequencies were examined, and comparison of the result with string theory, the flat taut string theory, axially-loaded beam theory, and M. Irvine’s theory was made. Estimation of cable damping ratio was then conducted using the free vibration data of the cable. Methods including logarithmic decrement method, half-power bandwidth method, Ibrahim time domain method and wavelet transform method were used to extract damping ratio. Comparison on the estimated cable damping with and without damper is finally discussed. The result provides valuable information on the cable control using passive or semi-active devices.