矩形细杆涡振幅值和驰振性能的对比风洞试验

Comparative Experiment on Vortex-induced Vibration Amplitude and Galloping of Slender Rectangular Cylinder

为了从试验上研究节段模型风洞试验结果与原型构件实际风振响应的对应关系,基于钢桁架桥梁大长细比杆件的工程背景,采用1根细长矩形钢管开展了原型杆件和按照1∶1比例设计的节段模型的对比测振风洞试验。节段模型与原型杆件具有相同的截面尺寸和基本一致的等效质量、阻尼比以及固有频率。在杆件长边迎风的状态下,原型杆件和节段模型测振风洞试验均实测到了涡激共振区间现象;在杆件短边迎风状态下,均实测到了两者对应的驰振现象。研究结果表明:原型杆件实测的涡激共振位移幅值稍大于节段模型,而两者的驰振性能基本相同。

In order to investigate the relationship between section model wind tunnel test results and prototype structure wind induced vibration responses, the comparative experiment was performed. On the basis of engineering background of slender members of steel truss bridges, a slender rectangular cylinder was selected as the prototype structure to conduct the vibration wind tunnel tests. A one to one section model was designed to make sure that the prototype cylinder and the section model shared the same cross section dimension, equivalent mass, damping ratio and natural frequency. The VIV lock-in ranges were both observed when the prototype cylinder and section model faced wind with their long edges and the non-divergent type galloping was measured when they faced wind with their short edges. The results indicate that the prototype cylinder achieves a slightly higher VIV amplitude than the section model; whereas their galloping behaviors are proved to be almost the same.