悬索桥铰接式吊索涡激振动气动干扰效应数值分析

发布时间：2018-11-12 10:34

【摘要】：众所周知,悬索桥是以承受拉力的缆索作为重要承重构件的桥梁,是典型的柔性结构,而由于悬索桥桥梁结构自重轻,阻尼低,在常风速的条件下,悬索桥桥梁及其构件(如主梁、主缆、吊索等)极易发生涡激共振响应,因此,对于悬索桥铰接式吊索的涡激振动研究是很有必要的,也是很有意义的。为了探讨用数值方法研究悬索桥吊索涡激振动现象,本文以某大跨径悬索桥铰接式吊索为背景,采用计算流体力学软件CFX和ANSYS结构建模软件Workbench相结合的流固耦合模拟方法进行悬索桥铰接式吊索的涡激振动数值模拟,模拟得到铰接式吊索发生涡激共振时的相关参数,求出最大振幅及吊索发生涡激共振时的锁定风速,具有一定的工程实用价值。首先,本文参考已有文献分别建立了二维单圆柱绕流模型和二维单圆柱流固耦合模型,分别进行了单圆柱绕流计算和单圆柱流固耦合计算,得到绕流及流固耦合的相关参量,并与已有参考文献进行了对比分析,验证了本文所使用的流固耦合模拟方法的正确性;其次,利用本文的建模方法和流固耦合模拟方法建立并计算了并列两圆柱在两种不同湍流模型(RNG??-和SST??-湍流模型)下的涡激振动响应,对这两种不同的湍流模型的计算结果进行比较分析,得到相应的结论:在进行并列两圆柱涡激振动数值计算时,两种湍流模型的结果存在一定差异,而且从结果可以看出SST??-湍流模型的数值模拟结果更加接近于实验值,SST??-湍流模型优于RNG??-湍流模型;最后,利用本文的建模方法建立了某大跨径悬索桥铰接式吊索的二圆柱吊索流固耦合模型,采用有限元软件ANSYS对五种不同长度的吊索(D39号、D41号、D44号、D46号和D49号吊索)进行模态分析,以确定吊索的自振频率,进而确定吊索的刚度及阻尼;选取其中的三种吊索(D39号、D44号和D46号吊索)进行涡激振动仿真计算,分别计算了这三种不同长度吊索的涡激振动响应,得到吊索发生涡激振动的锁定风速,发生涡激振动时吊索的最大振幅等,得到结论:D39号、D44号和D46号吊索发生涡激振动的锁定风速依次增大,而D39号吊索的锁定风速较D44号吊索和D46号吊索小得多,说明D39号吊索在较低风速下最容易发生涡激振动,在实际工程中要做好抑振措施。
[Abstract]:As we all know, suspension bridge is a typical flexible structure, which takes cable bearing force as an important load-bearing component. However, because of its light weight and low damping, the suspension bridge is under the condition of constant wind speed. The vortex-induced resonance response of suspension bridge and its components (such as main girder, main cable, sling and so on) is easy to occur. Therefore, it is necessary and meaningful to study the vortex-induced vibration of suspension bridge hinged slings. In order to study the vortex-induced vibration of suspension bridge by numerical method, this paper takes the hinged slings of a long-span suspension bridge as the background. The numerical simulation of vortex-induced vibration of hinged slings of suspension bridges is carried out by using the fluid-structure coupling simulation method of CFX and ANSYS structure modeling software Workbench. The relevant parameters of vortex-induced resonance of hinged slings are obtained by simulation. It is of great practical value to calculate the maximum amplitude and the locked wind speed when the sling resonates with vortex-induced resonance. First of all, two dimensional single cylinder flow model and two dimensional single cylinder fluid-solid coupling model are established with reference to the previous literatures. The calculation of single cylinder flow and single cylinder fluid-solid coupling are carried out respectively, and the related parameters of flow and fluid-solid coupling are obtained. The results are compared with the references, and the validity of the fluid-solid coupling simulation method used in this paper is verified. Secondly, the vortex-induced vibration responses of two parallel cylinders under two different turbulence models (RNG??- and SST??- turbulence models) are established and calculated by using the modeling method and the fluid-solid coupling simulation method in this paper. The results of the two different turbulence models are compared and analyzed, and the corresponding conclusions are obtained: the results of the two turbulence models are different when the vortex-induced vibration of two parallel cylinders is numerically calculated. From the results, it can be seen that the numerical simulation results of the SST??- turbulence model are closer to the experimental results, and the SST??- turbulence model is better than the RNG??- turbulence model. Finally, the fluid-solid coupling model of two cylindrical slings of a long span suspension bridge with hinged slings is established by using the modeling method in this paper. The finite element software ANSYS is used to analyze five kinds of slings of different lengths (D39, D41, D44). In order to determine the natural vibration frequency of the sling and then determine the stiffness and damping of the sling, the modal analysis is carried out for D46 and D49 sling. Three kinds of sling (D39, D44 and D46 sling) are selected to simulate the vortex-induced vibration. The vortex-induced vibration responses of the three slings of different lengths are calculated respectively, and the locked wind speed of the vortex-induced vibration of the sling is obtained. It is concluded that the locking wind speed of Vortex excited vibration of D39, D44 and D46 sling increases in turn, while the locked wind speed of D39 sling is much smaller than that of D44 and D46 sling. It is shown that the vortex vibration of D39 sling is most likely to occur under low wind speed, and the vibration suppression measures should be done well in practical engineering.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3;U448.25

【参考文献】