桥梁断面颤振导数识别的随机搜索方法  

Identification of flutter derivatives of bridge decks on the basis of stochastic search technique

作　　者：许福友[1] 陈艾荣[1] 马如进[1] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《土木工程学报》2006年第7期63-68,共6页China Civil Engineering Journal

基　　金：国家自然科学基金(50478109)

摘　　要：建立了识别颤振导数的普适性更强的分析模型,该模型可适用于竖弯与扭转信号长度不同的情形;阐明总体最小二乘法加权理论,推导了对数衰减简谐函数平均值和标准差计算公式;提出随机搜索方法用于搜索信号特征的最佳拟合值;仿真算例表明,随机搜索方法是有效可行的,并且计算精度令人满意。融合随机方法,分别采用竖弯、扭转分项和总体最小二乘法对苏通大桥主梁断面颤振导数进行识别;识别结果表明,相对分项最小二乘而言,总体最小二乘并不能显著提高颤振导数的识别精度。A more applicable analytical model for extracting flutter derivatives is proposed, which is suitable for different lengths of vertical and torsional signals. The weighting theory for the unified least-square method is expounded. The formulas of the means and standard deviation of logarithmic decaying harmonic function are deduced. A stochastic technique for searching the optimal fitting values of signal properties with satisfactory precision is developed, which is verified to be a valid and feasible method by using two simulation examples. Flutter derivatives of Sutong Bridge deck are extracted by combining the stochastic search technique with the independent vertical, the torsional and the unified least-square methods, respectively. The results indicate that the unified least-square method cannot significantly improve the precision of flutter derivative identification, when compared with the vertical and the torsional least-square method.

关 键 词：桥梁 颤振导数识别 最小二乘法 随机搜索方法 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]