桥梁吊杆典型风致振动幅值响应质量阻尼效应研究  

Mass damping effects for typical wind-induced vibration amplitude responses of bridge hangers

作　　者：周帅[1,2] 罗桂军 牛华伟 陈政清[1] ZHOU Shuai;LUO Guijun;NIU Huawei;CHEN Zhengqing(College of Civil Engineering,Hunan University,Changsha 410082,China;China Construction Fifth Engineering Division Corp.,Ltd.,Changsha 410004,China)

机构地区：[1]湖南大学土木工程学院,长沙410082 [2]中国建筑第五工程局有限公司,长沙410004

出　　处：《振动与冲击》2021年第18期63-69,93,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金(51708202);湖南省科技创新计划(2019RS2051,2018JJ3577);中建股份重点课题(CSCEC-2020-Z-43)。

摘　　要：涡激共振与准定常驰振临界风速相近时,矩形杆件易发一种涡振与驰振耦合风致振动,区别于锁定区间涡振和发散性驰振,是一类响应幅值随风速的增加而线性增长的“软驰振”现象,质量、阻尼是影响耦合程度和估算幅值的关键参数。基于一组宽高比1.2∶1矩形截面杆件节段模型,通过调整模型系统等效刚度、等效质量和阻尼比,实现了Reynolds数一致情况下,相同质量不同阻尼比、相同阻尼比不同质量以及相同Scruton数不同质量、阻尼组合下风振响应对比试验研究。研究表明:耦合状态下,组成Scruton数的质量、阻尼参数对“软驰振”幅值响应的影响是独立的,权重相同;存在影响“软驰振”幅值响应Scruton数“锁定区间(12.4~30.6)”,“锁定区间”内,无量纲风速-幅值响应曲线线性斜率(Slope)不随Scruton数变化而变化,并存在一个使风致振动由耦合状态转变为非耦合状态的Scruton数“过渡区间(26.8~30.6)”;修正了“软驰振”响应幅值估算经验公式,可用于类似工程杆件设计风速范围内的幅值预测。When the critical wind speed for the vortex induced resonance is close to that for the quasi steady galloping,a kind of coupled wind-induced vibration is easy to occur on a rectangular bar,which is different from the conventional vortex-induced vibration and divergent galloping.It is a kind of“soft galloping”phenomenon that the response amplitude increases linearly with the increase of wind speed.The mass and damping are the key parameters that affect the coupling degree and the amplitude response estimation.Based on a set of models with 1.2 width-height-ratio rectangular section member,by adjusting the equivalent stiffness,the equivalent mass and the damping of the model system,contrast experiments on the wind-induced vibration responses were carried out in the following cases:the same mass with different damping,the same damping with different mass and the same Scruton number with different mass and damping combination under the condition of uniform Reynolds number.The results show that in the coupling state,the influences of mass and damping parameters on the amplitude responses of“soft galloping”are independent and the weights are the same;for the“soft galloping”amplitude response,there is a Scruton number“locked interval(12.4-30.6)”.In the“locked interval”,the linear slope of the dimensionless wind speed amplitude response curve does not change with the Scruton number.Moreover,a“transition interval(26.8-30.6)”for the Scruton number coexists,where the coupled wind-induced vibration state is transferred to uncoupled state;the empirical formula for“soft galloping”response amplitude estimation is modified,which can be used to predict the amplitude within the designed wind speed range of similar engineering members.

关 键 词：涡激共振 驰振 耦合振动 Scruton数 幅值估算 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]