大跨度柔性斜拉-悬索体系风致静动力响应研究

在风作用下大跨度斜拉-悬索体系具有明显的三维流动特点, 其风效应较为复杂, 同时斜拉-悬索体系跨度大、刚度小、对风作用较为敏感, 易产生风致振动。该文以空中客车系统为工程背景, 首先通过1∶1足尺节段模型风洞试验得到主缆和轨道的气动力系数, 然后在分析风、主缆、轨道三者相互作用的基础上, 对有限元分析软件ANSYS进行二次开发, 建立风、主缆、轨道非线性空间分析模型, 通过风荷载的自动加载, 实现风致静动力响应全过程仿真模拟, 从而得到主缆、轨道的静动力响应。计算结果表明, 结构整体表现较柔, 在设计风速下轨道和主缆横向位移较大, 结构横向总响应较竖向总响应要大得多, 结构总响应以横桥向为主。研究结论可为大跨度柔性斜拉-悬索体系的进一步优化设计提供依据。

WIND-INDUCED STATIC AND DYNAMIC RESPONSE OF LONG SPAN CABLE-STAYED-SUSPENSION SYSTEMS

Cable-stayed-suspension systems are characterized by the obvious three-dimensional ambient flow under wind action, which is actually a kind of complex wind effect. The cable-stayed-suspension system is sensitive to wind action and is prone to vibration due to its long span and flexibility. Taking the aerobus systems as engineering background, the aerodynamic coefficients of the main cable and guideway are firstly measured by a wind tunnel test with an 1∶1 scale section model. Then, considering the interactions of wind, cable and guideway, the secondary development of the finite element software ANSYS has been carried out. The whole process of wind induced static and dynamic responses is simulated by automatical loading on the basis of the nonlinear three-dimensional finite element model of wind, cable and guideway. Finally, the static and dynamic responses of the cable and the guideway are obtained. The results show that the structure is flexible, and the lateral displacement of the cable and guideway is comparatively large at the design wind speed. The lateral response is dominated and much larger than the vertical response. The research conclusions can provide a reference for the design optimization of long span cable-stayed-suspension systems.