Investigation On Nonlinear Dynamics Behavior Of Stay Cables Under Rain-wind Induced Vibration

Cable structure plays an important role in the engineering practice , which length areimproved with the increasing of the span of cable-stayed bridge . Inclined cable are prone tovibrate under the conditions of natural environment for its characteristics of high flexibility ,large slenderness and low damping , and the rain-wind induced vibration is one of thedominant forms . The cable fatigue failure inside the anchor and the damage tocorrosion-resistant materials on the surface of the cable caused by large amplitude vibrations ,which can affect the safe operation of the cable-stayed bridge seriously . Rain-wind-inducedvibration presents great complexity , which formation mechanism has a jillion problems arepressing for solution . So in resent decades , research on the rain-wind-induced vibration hasbecome one of the focus issues .On the basis of the thing that forefathers study , this paper consider there exist restoringforce when the cable and the rivulet occur mutual movement , simultaneously , damping forceis assumed to exist in the system . Use Alembert principle to establish two-degree couplednonlinear motion differential equations of rain-wind-induced vibrations of cable structure ,The system is analyzed by numerical calculated with mathematic program . The phasediagrams of the cable and the water-line are achieved , it shows that their momentsconverged to stable limit cycle . Then analyze the density ratio、viscosity and other parameterson the effect of the cable amplitude , indicating that they are important factors for cableamplitude . also analyze the relationship between the cable amplitude and wind velocity , therelationship chart show the“speed limit”,“amplitude limit”feature of the rain-wind-inducedvibration of the cable . Through the calculation of the Lyapunov performance index by Matlabprogram obtained the system exist chaotic region. The Phase trajectory and the time-historycurve with time extension will be increasingly larger , which can,t be predicted , thus thechaos phenomenon of system being better interpreted . A good coupling relationship betweenthe cable and the rivulet is founded in the numerical analysis , and the movement phase of thecable and the water rivulet performances reversed phase , The motion characteristics of therivulet appears as sine discipline basically . Finally , introduce some corresponding controlmeasures to the rain-wind-induced vibration of the cable , in which the damper is a perfectsuppression measures .