基于数值模拟的π形主梁断面颤振导数研究

发布时间：2018-03-22 14:18

本文选题：π形断面　切入点：颤振导数　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：桥梁的风致振动研究中,颤振稳定性分析是必不可少的,桥梁颤振是发散性的自激振动,一旦发生,会造成毁灭性的灾难。颤振导数是大多数现有颤振分析方法的核心,是决定颤振临界风速的关键参数。本文围绕π形断面的颤振导数主要作了以下工作:首先简要介绍了桥梁风致效应,并回顾了桥梁颤振稳定性研究的发展历程和近况;对桥梁断面颤振导数的识别理论及方法做出总结分析,为本文的风洞试验和数值模拟提供理论基础;介绍了计算机流体动力学基本理论,分析并确定了适合本文的分状态强迫振动算法和数值模型。然后对带风嘴的π形主梁断面分别进行风洞试验和数值模拟识别其颤振导数,对比二者结果,四个主颤振导数值吻合较好,四个副颤振导数在个别工况下差异略大,总体来说可用本文的数值算法识别π形断面的颤振导数。通过数值模拟结果,分析了风攻角对π形断面八个颤振导数的影响。最后,提出了π形断面的尺寸系数φ,定义φ为π形断面宽度B与两腿间距L的比值,数值计算了四种尺寸系数下的π形断面,研究尺寸系数φ对颤振导数的影响,结果表明不同风攻角、不同风速下,φ对各个颤振导数影响有差异,要结合风攻角与来流风速考察各个颤振导数随φ的变化情况;同一风速下,φ对A1、A2、A4三个颤振导数几乎没有影响;当风攻角为0°、+3°、+5°时,φ对H4也没有影响;其他工况时,尺寸系数φ对π形断面的五个颤振导数影响程度各不相同。
[Abstract]:In the study of wind-induced vibration of bridges, flutter stability analysis is essential. Bridge flutter is self-excited vibration with divergence, once it occurs, it will cause devastating disaster. Flutter derivative is the core of most existing flutter analysis methods. This paper focuses on the flutter derivatives of 蟺 shaped section. Firstly, the wind-induced effects of bridges are briefly introduced, and the development and recent development of flutter stability of bridges are reviewed. The identification theory and method of flutter derivative of bridge section are summarized and analyzed, which provides a theoretical basis for wind tunnel test and numerical simulation in this paper, and introduces the basic theory of computer fluid dynamics. This paper analyzes and determines the algorithm and numerical model of forced vibration in separate states for this paper. Then wind tunnel test and numerical simulation are carried out to identify the flutter derivatives of 蟺 shape main beam section with wind nozzles, and the two results are compared. The numerical results of the four main flutter conductors agree well, and the four auxiliary flutter derivatives vary slightly under individual working conditions. In general, the numerical algorithm in this paper can be used to identify the flutter derivatives of 蟺 shaped sections. The influence of wind attack angle on the eight flutter derivatives of 蟺 shaped section is analyzed. Finally, the dimension coefficient 蠁 of 蟺 shaped section is proposed, which is defined as the ratio of the width of 蟺 shaped section B to the distance between two legs, and the 蟺 shaped section with four dimension coefficients is numerically calculated. The effect of dimension coefficient 蠁 on flutter derivative is studied. The results show that the influence of 蠁 on flutter derivative is different under different wind attack angle and different wind speed. Under the same wind speed, 蠁 has almost no effect on the three flutter derivatives of A _ (1) A _ (2) A _ (2) A _ (4), 蠁 has no effect on H _ 4 when the attack angle is 0 掳, 3 掳and 5 掳, and the influence degree of dimension coefficient 蠁 on the five flutter derivatives of 蟺 section is different under other conditions.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3

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