检修车轨道位置对钢箱梁涡振特性的影响

Influence of maintenance track position on vortex vibration characteristics of steel box girder

为了研究检修车轨道位置变化对结构气动稳定性的影响,以一座闭口钢箱梁断面的大跨径悬索桥为研究对象,通过节段模型风洞试验得到不同检修车轨道位置下结构的涡振位移响应,并采用计算流体力学方法进行典型工况下的断面周围流场模拟,进一步探究了检修车轨道位置影响断面涡振特性的内部机理。结果表明:检修车轨道位置对断面的竖向涡振和扭转涡振均有明显影响,检修车轨道位于中部或者边缘时都会减弱断面的涡振稳定性,尤其是当检修车轨道位于边缘时会诱发大幅扭转振动;涡振主要由尾流涡脱引起,检修车轨道位置的改变会使尾流涡脱的尺寸和位置发生变化,从而进一步影响主梁断面的涡振稳定性;当检修车轨道相对位置为0.75时,尾流及检修车轨道附近旋涡微弱,流场稳定性最优。

In order to study the influence of position change of maintenance track on aerodynamic stability of structures,a long-span suspension bridge with closed steel box girder section is taken as the research object.The vortex vibration displacement response of the structure under different positions of maintenance tracks is obtained through the segmental model wind tunnel test.The computational fluid dynamics(CFD)method is used to simulate the flow field around the section under typical working conditions,and the internal mechanism of the influence of the maintenance track position on the vortex vibration characteristics of the section is further explored.The research results show that the location of the maintenance track has obvious influence on the vertical and torsional vortex vibration of the section.When the maintenance track is located at the middle or edge,the vortex vibration stability of the section will be deteriorated.Especially when the maintenance track is located at the edge,large amplitude torsional vibration will be induced.The numerical simulation results of the flow field show that the vortex vibration is mainly caused by the wake vortex shedding,and the change of the position of the maintenance track will change the size and position of the wake vortex shedding,thus further affecting the vortex vibration stability of the section.When the relative position of the track is 0.75,the vortex near the wake and repair track is weak and the flow field stability is optimal.