基于气动参数之间关系的桥梁断面气动导纳识别

气动导纳的准确估计对大跨桥梁抖振分析具有重要意义.目前在识别方法、试验技术等方面均有诸多进展,但尚未建立识别全部气动导纳函数的方法.针对这一问题,基于气动导数与气动导纳之间的关系,结合根据紊流风场中的抖振响应同时识别桥梁结构气动导数和气动导纳这一思路,首先采用随机子空间法识别得到紊流风场中桥梁结构的气动导数,然后利用气动导数与气动导纳之间的近似关系获取与竖向脉动风分量对应的气动导纳函数,最后根据抖振力谱和脉动风速谱来确定与水平向脉动风分量对应的气动导纳函数.实例研究表明,本文方法对流线型断面气动导纳的识别是可行的.

Estimation of aerodynamic admittance functions of long-span bridges by the relationships among aerodynamic parameters

Accurate estimation of aerodynamic admittance functions for large-span bridges is of critical importance to ensure the reliability of buffeting analysis. Although much progress has been achieved both in the identification and testing methodologies of aerodynamic admittance functions, complete aerodynamic admittance functions can not be extracted in grid or boundary turbulence. In this paper, based on the relationships between flutter derivatives and aerodynamic admittance functions, a new method has been proposed to identify the complete aerodynamic admittance functions. The method was experimentally verified by wind tunnel tests, which were conducted to experimentally determine the flutter derivatives and aerodynamic admittance functions of a streamlined thin plat model. However, for bluff body, the feasibility of the present method could not be recognized.