摘要
传统的大跨度桥梁抖振分析通常依赖于等效式气动导纳函数,认为气动导纳的纵向和竖向分量相等,该假定可能因复杂的流固作用而导致难以预测的计算误差。为了在抖振分析中区分风场纵向和竖向脉动分量的不同贡献,基于前期研究已得到的分离式气动导纳(包括气动导纳纵向分量(u-component of aerodynamic admittance function,u-AAF)、气动导纳竖向分量(w-component of aerodynamic admittance function,w-AAF)),首先在脉动风场模拟中对u-AAF、w-AAF进行时域化处理,得到考虑了风场纵向、竖向脉动分量不同贡献的抖振力时程,然后基于ANSYS软件开展了大跨悬索桥抖振响应时域分析,评估了基于等效式气动导纳所得抖振响应的误差。结果表明,低频区域气动导纳较高频区域气动导纳对于竖向抖振响应的贡献更大。在0°风攻角下,等效式气动导纳所得抖振响应误差很小(1.94%);而在2°~8°风攻角下,等效式气动导纳所得抖振响应误差为26.39%~61.20%,其中在4°风攻角时误差最大。可见,以往抖振分析中将风场纵向、竖向脉动分量视为等效会高估实际抖振响应,大跨度桥梁抖振分析应考虑风场脉动分量的方向性差异。
Traditional buffeting analysis of long-span bridges usually relies on equivalent aerodynamic admittance function,assuming that the longitudinal and vertical components of aerodynamic admittance are equal.This assumption,however,may lead to unpredictable calculation errors due to complex fluid structure interactions.In order to distinguish the different contributions of longitudinal and vertical components of aerodynamic admittance related to turbulent fluctuating components in buffeting analysis,based on the separated aerodynamic admittance functions obtained from previous studies(including the u-component of aerodynamic admittance function(u-AAF)and the w-component of aerodynamic admittance function(w-AAF))the time domain transformations were firstly conducted to obtain the buffeting force time history considering the different contributions of turbulent wind longitudinal and vertical fluctuating components.And then,the buffeting time-domain was performed on a suspension bridge by ANSYS software.Finally,the error of buffeting response based on equivalent aerodynamic admittance was evaluated.The results indicate that the contribution of aerodynamic admittance in the low-frequency region to the vertical buffeting response is greater than that in the high-frequency region.As the angle of attack is zero,the equivalent aerodynamic admittance has a small error(1.94%)in the buffeting response.While the angle of attack is within the range of 2°-8°,the error reaches 26.39%-61.20%,with the maximum error occurring at 4°angle of attack.It can be seen that in previous buffeting analysis,treating the longitudinal and vertical fluctuating components of turbulent wind field as equivalent would overestimate the buffeting response.Therefore,the directional differences of turbulent components should be considered in buffeting analysis of long-span bridges.
作者
吴波
徐鸣馨
辛景舟
程崇晟
吴凤波
于和路
WU Bo;XU Mingxin;XIN Jingzhou;CHENG Chongsheng;WU Fengbo;YU Helu(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《振动与冲击》
北大核心
2025年第24期128-137,共10页
Journal of Vibration and Shock
基金
国家自然科学基金项目(52108435,52308146)
重庆交通大学研究生科创项目(2024S0012)。
关键词
桥梁抖振
气动导纳
紊流风场脉动分量
抖振时域分析
bridge buffeting
aerodynamic admittance
fluctuating components of turbulent wind field
buffeting time domain analysis
