桥梁主梁颤振临界风速预测的瞬时功率平衡算法  

Instantaneous power balancing algorithm for critical wind speed prediction on flutter of bridge girders

作　　者：赵林[1,2] 程樾 刘圣源 方根深[1,2] 崔巍 葛耀君[1,2] Zhao Lin;Cheng Yue;Liu Shengyuan;Fang Genshen;Cui Wei;Ge Yaojun(State Key Lab of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Transport Industry of Wind Resistant Technology for Bridge Structures,Tongji University,Shanghai 200092,China;Huaneng Clean Energy Research Institute,Beijing 102209,China)

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 [2]同济大学桥梁结构抗风技术交通行业重点实验室,上海200092 [3]中国华能集团清洁能源技术研究院有限公司,北京102209

出　　处：《土木工程学报》2023年第9期90-99,共10页China Civil Engineering Journal

基　　金：国家自然科学基金(52078383,52008314,51978527);土木工程防灾国家重点实验室自主课题(SLDRCE19-B-11)。

摘　　要：桥梁跨度的持续增大导致其风致振动问题尤为突出,其中颤振失稳作为一种发散性振动是大跨度桥梁抗风研究的关键内容。基于颤振临界状态瞬时功率平衡的思路,采用非线性优化提出一种大跨度桥梁颤振临界风速预测的算法。针对弯扭耦合的两自由度运动系统,二维桥梁断面的风致自激力和结构力对系统的能量贡献依赖于折算频率、风速以及竖向与扭转运动的幅值比和相位差。由此根据颤振临界状态瞬时功率平衡的原则,将颤振临界状态的预测转变为瞬时功率平衡目标函数最小值的求解问题。采用薄平板断面进行颤振临界状态分析,通过与节段模型风洞试验和经典二维颤振分析方法结果对比,验证基于瞬时功率平衡颤振分析方法的可行性和准确性。相较于以受力平衡为主要特点的传统分析方法,所提方法更加清晰且量化地呈现出颤振过程多种气动力分量之间的贡献关系,能够精准描述桥梁断面颤振发生时的系统状态,实现结构颤振临界状态的合理评估。With the continuous increase of bridge span,the wind-induced vibration is particularly prominent.Flutter instability,as a kind of divergent vibration,is the key content of wind resistance research of long-span bridges.Based on the principle of instantaneous power balance of critical state of flutter,an algorithm for predicting critical wind speed of flutter of long-span bridges was proposed by utilizing nonlinear optimization strategy.For the 2-D motion system of bending-torsional coupling,the contribution of wind-induced self-excited force and structural force of the two-dimensional bridge section to the energy of the system is related to the reduced frequency,wind speed,the amplitude ratio of vertical to torsional motion and the phase lag between vertical and torsional motion.Therefore,according to the principle of instantaneous power balance in critical state of flutter,the prediction on critical state of flutter is transformed into the extreme value optimization problem of instantaneous power balance objective function.By comparing with the segmental model wind tunnel test results and the classical two-dimensional flutter analysis results based on the thin and flat plate,the feasibility and accuracy of the proposed algorithm based on instantaneous power balance are verified.Compared with the traditional methods characterized by the force balance,the proposed method can more clearly and quantitatively presents the contribution relationship between multiple self-excited aerodynamic components,and can accurately describe the system state when the bridge section flutter occurs,which may be used to evaluate the critical state of flutter reasonably.

关 键 词：颤振 瞬时功率平衡 临界风速预测 桥梁主梁 薄平板 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]