风速对水线及斜拉索振动的影响

斜拉桥拉索的风雨激振是特定风速及降雨条件下的低频、大幅度振动，为研究风速对斜拉索风雨激振的影响，本文将两自由度滑移理论模型与Comsol软件相结合，大幅提高了计算效率，通过数值计算得到了不同风速下的水线运动规律、拉索气动力变化规律及其振动响应。结果表明：斜拉索发生风雨激振时，横风向振幅约为顺风向振幅的两倍；只有当风速处于特定风速范围内时，斜拉索才会发生明显的风雨激振现象，此时上水线振荡频率及气动力变化频率均接近拉索自振频率，水线与拉索间的共振是风雨激振的主要原因之一。
Abstract：Rain-wind induced vibration (RWIV) is a large amplitude and low frequency vibration of cables of cable-stayed bridges under simultanuous wind and rain.In order to investigate the effects of wind velocity on the RWIV,a 2-DOF slip model based on the lubrication theory was built and combined with the Comsol software to enhance the efficiency of numerical calculation.The characteristics of rivulet movements,aerodynamic forces and cable vibrations were investigated by numerically solving the coupled equations of the water film and cable.The results show that the amplitude of cable vibration in across-wind direction is double that in along-wind direction.RWIV only occurs in a special range of wind velocities,while the frequencies of upper rivulet oscillation and aerodynamic forces are both close to the cable natural frequency.The resonance between rivulets and cables is one of the main causes of RWIV.