Study On Vibration Control Of Super Long Stay Cable

With the increase of cable span,super long stay cables have been applied more and more widely.With the increase of length,the stiffness and damping of super long stay cables are greatly reduced,and all kinds of vibration are more likely to happen.In order to avoid the damage caused by the vibration of super long cable,it's particularly important for researching vibration control.On the basis of the analysis of the vibration characteristics of the super long slanted cable,the study of the vibration damping of the free vibration and the parameter vibration of the super long slanted cable is carried out by the Lever Mass Damper and Magnetorheological Fluid Damper.The main contents are as follows:(1)Based on Newton's law,the vibration equation of super long stay cable is established,and the first order natural frequency of super long stay cable is derived.The free vibration and parametric vibration of super long stay cables are numerically simulated,and the influence of relevant parameters on the vibration performance of super long stay cables is discussed.The results show that increasing the initial cable force or increasing the damping of cable structure can effectively reduce the amplitude of free vibration,which is an effective way to control vibration.For the suppression of parametric vibration,we should control the amplitude of external excitation rather than increase the damping of structure.(2)A model of super long stay cable-lever mass damper system is established.On the basis of dynamic characteristics analysis,the influence of leveraged damper on the parameter vibration of super long slanted cable is studied.The results show that the lever mass damper increases the stiffness of super long stay cables,shortens the effective length,and effectively suppresses parametric vibration.The effect of installation position,mass mass,spring stiffness and damping on the vibration of the parameter vibration is found to have the greatest impact on the parameter vibration of the ultra long cable.(3)A magnetorheological damper is installed on the super long stay cable,and the three-dimensional finite element model is adopted to study the damping effect of magnetorheological fluid damper.When the super long cable is subjected to free vibration and parametric vibration,the influence of relevant parameters on the damping effect of magnetorheological fluid damper is discussed.The results show that the initial cable force can be properly increased and the position ratio of the magnetorheological damper installed in 2 % to 2.5 % can meet the actual requirements and the requirements of the free vibration and the vibration of the parameters.Increasing the initial cable force of the super long cable,increasing the position ratio of the magnetorheological damper and the damping yield force not sure improve the control effect of the parameter vibration of the ultra long cable-magnetorheological fluid damper system.