苏通大桥气弹模型气动失稳分析  

Analysis of the aerodynamic divergence of an aeroelastic model of Sutong Bridge

作　　者：许福友[1] 陈艾荣[2] 

机构地区：[1]大连理工大学,辽宁大连116024 [2]同济大学,上海200092

出　　处：《土木工程学报》2007年第7期44-48,76,共6页China Civil Engineering Journal

基　　金：国家自然科学基金(50478109);高等学校博士点专项科研基金(20040247026)

摘　　要：大跨柔性桥梁气弹模型在风荷载作用下会产生明显的竖向、侧向位移和附加攻角。推导气弹模型实测位移修正表达式,对苏通大桥气弹模型高风速时实测位移进行修正,对比分析修正前后差异。绘制了苏通大桥主跨跨中断面、1/4断面和边跨跨中3个典型断面扭转中心的运动轨迹,分析其特点,对苏通大桥气弹模型气动失稳现象进行解释。基于随机搜索方法和随机子空间方法识别得到的模态参数,对苏通大桥气弹模型进行复模态颤振分析。分析结果表明:苏通大桥气弹模型可视为一种非常规索网复合系统,其气动失稳振动表现为保持平衡状态的竖向、侧向和扭转耦合滚动,扭转频率成分在竖弯和侧弯振动中参与很多,而竖弯和侧弯频率成分在其他两种振动中参与很少。Under wind loads, obvious vertical and lateral displacements and additional angle of attack occur for an aeroelastic model of long-span flexible bridge.. For displacement measurement of the aeroelastic model, modified expressions are derived. Under the condition of high wind velocity, the measured displacement of the Sutong Bridge aeroelastic model is corrected, and the difference between the original and the modified displacement is compared and analyzed. For Sutong Bridge deck, the kinematic trajectories of torsional centers of three typical sections （midspan section and 1/4-span section of main span and midspan of side span） are investigated. The aerodynamic divergence of the Sutong Bridge aeroelastic model is illustrated. Based on modal parameters identified by using a stochastic search algorithm and stochastic subspace identification technique, complex modal analysis of flutter for the Sutong Bridge aeroelastic model is carried out. The analytical results reveal that the Sutong Bridge aeroelastic model can be considered as an irregular composite cable-net system. At the air-actuated instability state, the system exhibits coupled vertical, lateral rotation and torsion. Torsion largely occurs in vertical and lateral vibration, whereas vertical and lateral modes are almost not involved in other two vibration modes.

关 键 词：苏通大桥 气弹模型 气动失稳 位移修正 模态耦合 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]