Improvement And Optimization Of Aerodynamic Shape Based On Imitated Water-Drop Cable-Stay Casing

Cable-stayed bridge is widely used in modern transportation engineering as a kind of bridge system. The span of cable-stayed bridge is increasing gradually and the cable-stayed also becomes longer with the development of designed theory, computational method and the rising of construction method, the equipped level. The cable-stayed appear vibration easily because of the cable-stayed is flexible member. The vibration control research of cable-stayed has become the focus on international and domestic researchers of Bridge and Wind engineering nowadays.The technology of resistance vibration is studied with the purpose of damping. Firstly, the paper processes from the influencing factors of arousing cable-stayed damping and a new kind of contour profile drop shape——imitated water-drop aerodynamic shape is presented basing on aerodynamic damping. The simulation model of the velocity and stress field is established basing on the fluid simulation software FLUENT of CFD. After that, the existing two aerodynamic dimension model is compared and the flow field distribution of different cross-section shapes is get. At last, the speed, pressure and drag coefficient of two kinds of aerodynamic shape is comparesd and analysedSecondly, in order to improve the ability of reducing the vibration, the paper carries on parameter optimization to the aerodynamic shape of imitated water-drop for the minimum resistance based on Genetic Algorithm of MATLAB when the fluid flows through cable-stayed. It can get the best mathematical expression. Through comparison of flow field distribution between the shapes that is before and after optimization, it gets the optimized model is more suitable for the shape improvement of cable-stayed.Thirdly, since the influence of the wind on structure wind is related with the direction. It finds that the wind-direction to the amplitude of cable-stayed vibration can have certain influence through numerical simulation about several special angles of wind-direction and comparison the resistance coefficient and pressure coefficient and so on. The best angles of wind-direction that is reduced the vibration is found. Lastly, A kind of adaptive control device that can make the casing of cable-stayed rotate is designed.