П型断面主梁软颤振特性及抑制措施研究

发布时间：2018-08-31 13:57

【摘要】：П型断面主梁为气动钝体结构,在非线性自激力作用下,极易发生软颤振现象.以某П型断面叠合梁斜拉桥为研究对象,通过节段模型风洞试验,研究了各种气动措施对П型断面主梁软颤振性能的影响.研究结果表明:П型断面主梁软颤振表现为弯扭自由度耦合的单频振动特征,且随着风速的增加,竖向振动参与度系数先减小后增大;安装风嘴可以增大系数,其振幅服从正态分布,振幅波动范围随风速及攻角变化而变化;风攻角为负时,П型断面主梁最易发生软颤振;设置桥面附属设施会提高软颤振的临界风速、减小软颤振的扭转振幅及振幅增长速率;设置风嘴会显著降低软颤振的振动响应,采用尖风嘴可以改善主梁的软颤振性能,且随着风嘴变尖,软颤振的临界风速有提高的趋势,软颤振扭转振幅有下降的趋势;П型断面主梁底部设置中央稳定板对其软颤振性能的影响不明显.
[Abstract]:The main beam with curved section is a pneumatic blunt body structure, and soft flutter is easy to occur under the action of nonlinear self-excited force. The influence of various aerodynamic measures on the soft flutter performance of the main girder with a section is studied by using wind tunnel tests on a cable-stayed bridge with superimposed beam with a section as the research object. The results show that the soft flutter of the main beam with curved section is the single frequency vibration characteristic of the coupling of bending and torsional degrees of freedom, and the participation coefficient of vertical vibration decreases first and then increases with the increase of wind speed, and the coefficient can be increased by installing the wind nozzles. The amplitude varies with the wind speed and the angle of attack. When the wind attack angle is negative, the soft flutter is most likely to occur in the main beam of the section. The critical wind speed of the soft flutter can be increased by setting the bridge deck auxiliary facilities. The torsional amplitude and amplitude growth rate of soft flutter are reduced, the vibration response of soft flutter is significantly reduced by setting wind nozzle, and the soft flutter performance of main beam can be improved by using cusp nozzle, and the critical wind speed of soft flutter increases with the tip of wind nozzle. The amplitude of soft flutter torsion has a downward trend, and the effect of central stabilizing plate on the soft flutter performance is not obvious.
【作者单位】：西南交通大学土木工程学院;西南石油大学土木工程与建筑学院;
【基金】：国家自然科学基金资助项目(51378443)
【分类号】：U441.3

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