正六边形斜拉索风雨激振抑振机理及减振效果分析

Analysis of Rain-Wind Induced Vibration Damping Mechanism and Effect of Regular Hexagonal Stay Cables

依据滑移理论,借助钝体绕流模型,使用COMSOL软件建立正六边形拉索截面模型并计算得到随时间变化的风压力系数和风摩擦力系数.代入MATLAB软件进行数值求解,得到拉索在风雨激振作用下的振动响应、气动升力、水膜形态变化和上水线振荡区间内水膜厚度时程变化.从这四个方面来探究正六边形拉索风雨激振的抑振机理和减振效果.结果显示:在同等风洞试验参数条件下,正六边形拉索相比圆形拉索,振动幅度大为降低,具有良好的减振效果和潜在工程应用价值.正六边形拉索波浪起伏的表面抑制了上水线的周期性环向振荡,减弱了拉索表面气动力变化的周期性,从而有效抑制了拉索的风雨激振现象.

Based on the slip theory and the flowing around a bluff body model,the regular hexagon cable section model was established and calculated by using COMSOL software to get wind pressure coefficient and wind friction coefficient varying with time.These two coefficients were substituted into MATLAB software for numerical solution to get vibration responses,aerodynamic lift,time-history variation of water film thickness in the oscillation interval of the upper rivulet and shape change of water-film.From these four aspects,the suppressing vibration mechanism and vibration reduction effect of rain-wind induced vibration(RWIV)was explored for the regular hexagon cable.The results show that the amplitude of the regular hexagon cable is much lower than that of circular cable under the same wind tunnel test parameters.Therefore,good damping effects and potential engineering application value are embodied in hexagon cable.The periodical and circular oscillation of the upper rivulet which are caused by the undulating surface of the regular hexagon cable is inhibited and the periodicity of the aerodynamic force changes on the cable surface is reduced,thereby the rain-wind induced vibration(RWIV)of the cable is inhibited effectively.