Vibration Of Cable Subjected To Deck Excitation And Vibration Reduction

In this paper, the basic concepts of cable vibration and the dynamic characteristics of cable will be detailed analyzed. Resonance parameters of the cable and cable vibration control mechanism will be brief represented. Through the derivation of motion equations, a new model of cable-damper-deck system, both fully reflect the actual project but also fully reflect the vibration characteristics of system is presented.Based on the string tension model, an approximate optimal design formula for a viscous damper attached to a stay cable was given by using an analyticall formulation for complex eigenvalue problem, assuming the ratio of damper installation length to cable length is very small, the study also shows that the stiffness of damper would influence the performance of damper.In previous studies, researchers assume that the damper's support is separated from the anchor plan of the stay-cable and the damper's support is stationary when the deck is vibrating. There is a lack of researches in the effect of the coupling of deck and the damper for the vibration of deck, which influences the performance of damper. A new cable-damper system model which is closer to the actual engineering phenomenon is presented. A solution is presented of the problem of vibrations of a taut cable equipped with a concentrated viscous damper, which considering the coupling of deck and the damper for the deck excitation. The solution is expressed in terms of damped complex-valued modes, leading to a transcendental equation for the complex eigenfrequencies and assuming the ratio of damper installation length to cable length is much smaller than 1. An accurate asymptotic approximation of the damping ratio of the lower modes is obtained. The study shows that the coupling of deck and the damper would influence the optimal external damping parameter, the effect would depend on the stay cable's angle of inclination, the damper position. The study also shows that the coupling of deck and the damper would increase optimum damping coefficient. Similar to a damper without considering the coupling of deck and the damper, a universal design curve of a damper also exists. Through numerical analysis of cable, coupled model show the impact on damper design.