摘要
为准确评估大跨悬索桥的颤振性能,建立平均风与气弹效应一体化气动力时域模型,研究平均风效应对悬索桥颤振临界风速与后颤振响应特性的影响。采用阶跃函数法建立悬索桥加劲梁断面的气动自激力时域模型,并通过伪稳态气动力扣除法解决时域分析中直接叠加气动自激力与平均风荷载会导致部分气动力被重复考虑的问题,从而构建平均风与气弹效应一体化气动力时域模型。以某大跨悬索桥为背景,基于该模型分析该桥加劲梁的颤振临界风速和后颤振性能。结果表明:平均风效应对加劲梁颤振临界风速具有一定的影响,考虑平均风效应后,加劲梁颤振临界风速稍有提高;平均风效应对加劲梁后颤振响应特性影响显著,考虑平均风效应后,加劲梁后颤振响应达到稳态极限环振动(LCO)所需的时间比不考虑平均风效应时明显缩短,且最终的LCO幅值也有所增大;后颤振频率随着风速的增加呈现递减趋势,相同风速下,考虑平均风效应时的振动频率比不考虑时有所降低。
A time-domain aerodynamic force model that reflects the relationship between mean wind effect and aero-elastic effect was built up to study the impact of mean wind effects on the flutter critical wind speed and post-flutter response characteristics of suspension bridges,aiming to accurately evaluate the flutter performance of long-span suspension bridge.A time-domain aerodynamic self-excited force model of the stiffening girder of suspension bridge was developed using indicial functions,and a method of subtraction of the pseudo-steady effects from the self-excited force model was introduced to address the issue that direct superposition of self-excited and mean wind loads in the time-domain flutter procedure will allow a part of aerodynamic forces to be repeatedly counted.The presented models have been applied to analyze the flutter critical wind speed and post-flutter responses of the stiffening girder of an existing suspension bridge.The results demonstrate that mean wind effects impact the flutter critical wind speed to a certain extent,and the flutter critical wind speed rises after counting the mean wind effect.The time required for the post-flutter response to reach a stable limit cycle oscillation(LCO)is significantly shorter than that without considering the mean wind effect,and the final LCO amplitude also increases.The post-flutter frequency decreases with the increase of wind speed,compared with the scenario of no mean wind effect at the same wind speed,the vibration frequency shows sign of decreasing.
作者
吴长青
吴肖波
张志田
WU Changqing;WU Xiaobo;ZHANG Zhitian(College of Civil Engineering and Architecture,Hunan Institute of Science and Technology,Yueyang 414006,China;National Key Laboratory of Bridge Intelligent and Green Construction,Wuhan 430034,China;College of Civil Engineering and Architecture,Hainan University,Haikou 570228,China)
出处
《桥梁建设》
EI
CSCD
北大核心
2023年第4期94-101,共8页
Bridge Construction
基金
国家自然科学基金项目(51938012,52268073)。
关键词
悬索桥
平均风效应
气弹效应
自激力时域模型
颤振临界风速
后颤振性能
稳态极限环振动
有限元法
suspension bridge
mean wind effect
aeroelastic effect
time-domain self-excited force model
flutter critical wind speed
post-flutter performance
stable limit cycle oscillation
finite element method
