大跨度悬索桥主梁颤振特性数值模拟与试验研究

发布时间：2018-03-25 21:48

本文选题：悬索桥　切入点：CFD　出处：《西南交通大学》2017年硕士论文

【摘要】：随着大跨度桥梁的广泛运用,其风致振动的敏感性问题日益受到关注。在风致振动中,颤振对于桥梁结构的安全有非常大的隐患。本文针对颤振进行重点研究,对于实际应用具有重要意义。首先,本文总结分析了桥梁风毁病害案例及特征,介绍了风对桥梁结构的作用类型和作用方式,综述了国内外颤振理论的发展和研究现状。介绍了 CFD数值模拟技术,给出了流体的基本运动方程,简要介绍了数值模拟的方法,以及数值模拟运用到的软件。其次,介绍了湍流的数值模拟方法,介绍了某大跨度悬索桥的工程背景,以其主梁断面为研究对象,建立三种湍流模型下的数值模型,利用Fluent进行数值模拟,识别了断面的8个颤振导数,并与理论解对比,研究湍流模型对颤振导数识别的影响;改变湍流度,观察在不同湍流度下的识别模拟表现,研究湍流度对颤振导数识别精度的影响;改变强迫振动振幅,观察在不同振幅下的识别模拟表现,探讨了振幅对识别精度的影响。介绍了利用颤振导数,计算悬索桥主梁颤振临界风速的方法。最后,建立基于全桥的ANSYS有限元模型,分析研究了悬索桥的动力特性,获取风洞试验参数。通过主梁节段模型颤振性能的风洞试验,利用直接颤振法测定了结构成桥及施工态的颤振临界风速,利用颤振导数计算了主梁颤振临界风速,分析评价了主梁的颤振稳定性,在此基础上提出气动优化方案,并进行试验比较。
[Abstract]:With the wide application of long-span bridges, the sensitivity of wind-induced vibration has been paid more and more attention. In wind-induced vibration, flutter has great hidden danger to bridge structure safety. It is of great significance for practical application. Firstly, this paper summarizes and analyzes the cases and characteristics of bridge wind damage disease, and introduces the type and mode of action of wind on bridge structure. This paper summarizes the development and research status of flutter theory at home and abroad, introduces the CFD numerical simulation technology, gives the basic equations of motion of fluid, briefly introduces the method of numerical simulation and the software used in numerical simulation. The numerical simulation method of turbulence is introduced, and the engineering background of a long-span suspension bridge is introduced. Taking the section of its main beam as the research object, the numerical models under three kinds of turbulence models are established, and the numerical simulation is carried out by using Fluent. Eight flutter derivatives of cross-section are identified, and compared with theoretical solutions, the influence of turbulence model on flutter derivative identification is studied. The effect of turbulence on the identification accuracy of flutter derivatives is studied, and the effect of amplitude on identification accuracy is discussed by changing the amplitude of forced vibration, observing the performance of identification simulation under different amplitudes, and introducing the use of flutter derivatives. Finally, the ANSYS finite element model based on the whole bridge is established, and the dynamic characteristics of the suspension bridge are analyzed, and the wind tunnel test parameters are obtained. The flutter critical wind speed of the bridge and its construction state is measured by direct flutter method. The flutter critical wind speed of the main beam is calculated by using flutter derivative, and the flutter stability of the main beam is analyzed and evaluated. On the basis of this, the aerodynamic optimization scheme is proposed. The experimental results were compared.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.3;U448.25

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