桥梁风致振动的混沌特性

发布时间：2018-05-04 19:50

本文选题：桥梁工程 + 风致振动　；参考：《交通运输工程学报》2014年03期

【摘要】：利用非线性理论和混沌时间序列分析方法,建立了桥梁风致振动的数学模型,开发了计算桥梁振动加速度时间序列Lyapunov指数的MATLAB程序,进行了桥梁涡振和颤振的风洞试验,分析了不同风攻角下的桥梁风致振动的阻尼比、Lyapunov指数与风速的关系以及涡振振幅与风速的关系,研究了桥梁颤振和涡振的混沌特性。试验结果表明:在颤振试验中,当风速小于颤振临界风速15.5m·s-1时,Lyapunov指数小于0,Lyapunov指数与阻尼比存在很大的相关性,当风速从3m·s-1增大为18m·s-1时,相空间逐渐发散;在涡振试验中,当风速从4.5m·s-1增大至8.5m·s-1时,Lyapunov指数大于0,桥梁发生明显涡振,并由多频振动逐渐转变为单频振动,相空间变为一个较为理想的圆。桥梁的涡振与颤振均属于混沌现象,低风速下的Lyapunov指数可用来预测高风速下的风致振动,并且利用相空间也能识别涡振与颤振。
[Abstract]:By using nonlinear theory and chaotic time series analysis method, the mathematical model of wind-induced vibration of bridges is established. The MATLAB program for calculating the Lyapunov exponent of bridge vibration acceleration time series is developed, and the wind tunnel tests of bridge vortex vibration and flutter are carried out. The relationship between the damping ratio Lyapunov exponent and wind speed of bridge wind-induced vibration at different attack angles and the relationship between the amplitude of vortex vibration and wind speed are analyzed. The chaotic characteristics of bridge flutter and vortex-induced vibration are studied. The experimental results show that there is a great correlation between the Lyapunov exponent and damping ratio when the wind speed is less than 15.5m s ~ (-1), and the phase space gradually diverges when the wind speed increases from 3m s ~ (-1) to 18m s ~ (-1). When the wind speed increases from 4.5m s ~ (-1) to 8.5m s ~ (-1), the vortex vibration of the bridge is obvious, and the phase space becomes an ideal circle from multi-frequency vibration to single-frequency vibration. The vortex vibration and flutter of the bridge are both chaotic phenomena. The Lyapunov exponent at low wind speed can be used to predict wind-induced vibration at high wind speed, and the vortex vibration and flutter can be recognized by using phase space.
【作者单位】：长安大学公路学院;长安大学理学院;
【基金】：国家自然科学基金项目(51078038) 土木工程防灾国家重点实验室开放基金项目(SLDRCE10-MB-02) 中央高校基本科研业务费专项资金项目(CHD2010ZD001)
【分类号】：U441.3

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