悬索桥主缆架设过程驰振性能时域分析

摘要

为了分析悬索桥主缆在架设过程中可能发生的驰振失稳,导出了直接基于体轴系的驰振气动力表达式,避免了现有驰振分析方法采用风轴系下的气动系数需要进行的坐标转换,得到了更为简洁的驰振判据表达式.建立了悬索桥主缆的简化有限元模型,分析了结构动力特性；通过CFD(计算流体动力学)分析,得到了施工过程中不同断面形状主缆的气动力系数曲线.最后,分别基于单自由度驰振模型和实桥三维驰振模型,采用时域法模拟了主缆的风致驰振现象.研究表明,单自由度驰振模型分析的驰振发振风速与理论结果较吻合,三维驰振模型能更真实地反映主缆的驰振性能.%In order to analyze the galloping instabilities of main cables, the quasi-steady aerodynamic force formula was derived in a body axial coordinate system to avoid the coordinate transformation of aerodynamic coefficients in a wind axial coordinate system in the existing galloping analysis methods. As a result, a more concise galloping criterion expression was obtained. A simplified finite element model for main cables of a suspension bridge was established to analyze the structural dynamic characteristics. And aerodynamic coefficient curves of main cables with different cross-sectional shapes during construction were obtained by the CFD (computational fluid dynamics) method. Finally, based on the time-domain analysis method, a single-degree-of-freedom model for galloping and a three-degree-of-freedom model for galloping were respectively used to simulate the wind-induced galloping of main cables. The research results show that the galloping critical wind velocity obtained by the single-degree-of-freedom model for galloping is good consistent with the theoretical result, and the three-degree-of-freedom model for galloping can reflect the real galloping performance of main cables much better.