基于微分法的大跨度桥梁三维颤振敏感性分析  

Sensitivity analysis of 3-D flutter of large-span bridge based on differential method

作　　者：翁祥颖 董锐[2] 葛耀君[3] WENG Xiangying;DONG Rui;GE Yaojun(Fujian Provincial Key Lab of Civil Engineering New Technology&Imformationize,Fujian University of Technology,Fuzhou 350118,China;College of Civil Engineering,Fuzhou University,Fuzhou 350118,China;State Key Lab for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]福建理工大学福建省土木工程新技术与信息化重点实验室,福州350118 [2]福州大学土木工程学院,福州350118 [3]同济大学土木工程防灾减灾国家重点实验室,上海200092

出　　处：《振动与冲击》2024年第7期205-213,共9页Journal of Vibration and Shock

基　　金：福建理工大学科研启动基金(GY-Z21012)。

摘　　要：桥梁颤振敏感性表征设计参数对颤振临界风速的影响,是探究桥梁颤振机理与提升颤振性能的重要工具。为帮助设计人员在设计阶段高效精准地获取结构动力特性及颤振导数对大跨度桥梁颤振性能的影响规律,提出一种基于直接微分法的桥梁三维颤振敏感性分析方法。该方法基于系统矩阵的左右特征向量正交特性,构建在设计参数小幅摄动时桥梁多模态耦合颤振规格化条件,结合颤振临界条件得到系统特征值及颤振临界风速对设计参数的敏感性。为检验该方法,以理想薄平板断面简支梁桥为算例,与有限差分方法进行比较,表明该方法具有较高的精度和计算效率。将该方法用于一座大跨度悬索桥的颤振敏感性分析,结果表明:对于采用闭口流线型主梁断面的大跨度桥梁,一阶对称竖弯和一阶对称扭转模态对桥梁颤振影响最大;增大桥梁结构的阻尼比、模态质量及基础扭弯频率比,均会提升桥梁颤振临界风速;颤振导数中,A_(2)^(*)影响最显著,A_(3)^(*)、A_(1)^(*)和H_(3)^(*)的影响次之,其它颤振导数的影响则基本可以忽略。Effects of design parameters characterizing bridge flutter sensitivity on flutter critical wind speed are important tools for exploring bridge flutter mechanism and improving flutter performance.Here,to assist designers in efficiently and accurately obtaining influence laws of structural dynamic characteristics and flutter derivatives on flutter performance of large-span bridge during design phase,a bridge 3-D flutter sensitivity analysis method based on direct differential method was proposed.This method was based on orthogonal characteristics of left and right eigenvectors of a system matrix to construct normalization conditions for multi-modal coupled flutter of bridge under small perturbation of design parameters.Combining flutter critical conditions,sensitivities of system eigenvalues and flutter critical wind speed to design parameters were obtained.To examine the proposed method,a simply supported beam bridge with ideal thin flat plate cross-section was taken as an example,the results obtained with the proposed method was compared with those obtained with the finite difference method,it was shown that the proposed method has higher accuracy and computational efficiency.The proposed method was applied in the flutter sensitivity analysis of a large-span suspension bridge.The results showed that for a large-span bridge with a closed streamlined girder section,the first-order symmetric vertical bending mode and the first-order symmetric torsion mode have the largest impact on bridge flutter;increasing damping ratio,modal mass and foundation torsion-bending frequency ratio of bridge structure can all increase the critical wind speed of bridge flutter;in flutter derivatives,A_(2)^(*) has the most significant impact on bridge flutter critical wind speed,followed by A_(3)^(*),A_(1)^(*) and H_(3)^(*),while the others can basically be ignored.

关 键 词：敏感性 桥梁颤振 微分法 动力特性 颤振导数 

分 类 号：TU375[建筑科学—结构工程]