Nonlinear Time History Vibration Analysis And Damping Control Of Long Span Bridge Cable-stayed Cable

As cable-stayed bridges continue to refresh their spanning records in recent years,the length of stay cables is also growing.Due to its low damping and high flexibility,vibration is easily caused and damage is caused.Therefore,it is necessary to conduct in-depth research on the vibration mechanism and vibration control of cable stays,and to provide some valuable references for engineering practice and scientific research.In this paper,a random traffic load of the bridge is programmed based on the cellular automata model(CA).The random wind load with spatial coherence is written based on the linear filtering method(AR).Taking Xiaoshawan Yellow River Bridge as the engineering background,the Midas Civil model under the effect of random traffic load and random wind load was established.The displacement time-history of the full-bridge cable-stayed tower end and beam end is obtained,and spectrum analysis is performed.The research shows that the displacement frequency of the end of the stay cable is concentrated in the low frequency range of 0~1HZ,and the natural frequency of the long cable of the stay cable is also concentrated.In this frequency band,it provides the basis for generating resonance conditions.Based on the above basis,a unified equation for three-dimensional vibration of cable stays considering the factors of nonlinearity,stiffness,spatial three-dimensional coupling,various excitations,etc.was established,and the vibration frequency of cable stays under the excitation of end displacement was established by the natural frequency and The end displacement disturbance term consists of.Then use 4-5 order Runge-Kutta numerical methods to matlab programming and numerical analysis.Studies have shown that the cable stays at the end of the ideal excitation,it can stimulate a large vibration;considering the spatial coupling effect,the frequency response of the slope cable displacement response disappears,and turns into a beat frequency overlay effect,showing increasing Trend.It is discussed that the ratio of the natural frequency of the end displacement to the cable stays is 2:1 parametric vibration,and the displacement response exhibits the same beat characteristics as the first-order forced resonance.Therefore,it is necessary to consider the displacement of the cable end and its coupled vibration in engineering.This paper also focuses on the vibration suppression and vibration control of stay cables under external excitation.The matlab program for solving the vertical vibration response of stay cables was compiled based on the weighted implicit difference scheme,and its correctness and accuracy were verified.Through this program,the vibration suppression mechanism of the damper installed at the end of the stay cable is studied.The research shows that the damping mechanism of the stay cable damper does not rely solely on energy consumption but on the cable damper.The installation position has a constraining effect,and the effective length of the vibration of the cable stay is reduced,so that the natural frequency is changed to achieve the purpose of vibration control.However,under the ideal excitation of the end displacement,the same horizontal damping coefficient damper installed on the two ends of the cable stays is more effective than the damper with the same horizontal damping coefficient installed on the beam end.However,the existence of the parameter vibration will cause the damper to be installed.The amplitude of the cable stays in reverse.