桥板颤振导数的比较和敏感性分析 第一部分:试验数据分析

Comparative and Sensitivity Study of Flutter Derivatives of Selected Bridge Deck Sections Part Ⅰ:Analysis of Experimental Data

为评估风载下桥板的性能,通常采用多年来发展的两个独特的方法(自由和强迫振动),从风洞模型试验中得到桥板气动弹性系数。尽管已有众多的研究者对每个技术优缺点进行分析,但文献中缺少对试验结果的系统比较。本研究的意义在于进行与长期颤振导数试验数据相关的评估,包括分析和解释自由和强迫振动两种方法的异同点。从2002年开始,美国的爱荷华州大学和日本的公立研究所着手进行桥颤振导数的研究。试验包括的截面类型很广,从矩形棱柱到改进型,尤其考虑了当前在大跨桥中采用空气动力学设计梁的趋势。同时系统地分析和比较了两种方法颤振导数的试验结果。在相关的论文中,对敏感性进行分析以研究大跨桥在气动弹性不稳定时颤振导数数据中所隐含的不同点。

Aeroelastic coefficients （ flutter derivatives） of bridge decks are routinely extracted from wind tunnel section model experiments for the assessment of performance against wind loading. Two distinct methods, developed over the years, are usually employed for this purpose （free or forced vibration）. Even though advantages and disadvantages of each technique have been highlighted by numerous researchers, few examples of a systematic comparison of the experimental results are available in the literature. The significance of this study is related to the evaluation of an extended set of experimental data on flutter derivatives, and includes the analysis and interpretation of the differences recorded through the two methods. The motivation for this work emerged from the United States-Japan Benchmark Study on Bridge Flutter Derivatives that Iowa State University （ISU） in the United States and the Public Works Research Institute （PWRI）in Japan, Initiated in 2002. Tests were designed to cover a wide range of solid cross sections, from bluff （rectangular prisms） to streamlined, in particular considering the current trend of engineers to use aerodynamically-designed girders for bridges with longer spans. In this paper, a systematic analysis and a comparison of laboratory results of flutter derivatives obtained at both institutions were performed. In a companion paper, a sensitivity study was performed to examine the implications of the perceived dissimilarities among flutter-derivative data sets on the aeroelastic instability of long-span bridges （single-mode and coupled-mode）.