台风非平稳激励下的悬索桥时域抖振分析
发布时间：2019-02-15 08:06
【摘要】：摘要：随着对极端风(台风、下击暴流等)风速时程非平稳特性的深入了解,以及大跨度桥梁朝着更轻、更柔的方向发展,位于台风多发地带的柔性体系桥梁(悬索桥,斜拉桥)在台风非平稳激励下的气动稳定性研究越来越受到重视。探索利用实测台风数据进行台风非平稳脉动风激励下的桥梁抖振响应的研究方法,对于进行桥梁精细化抖振分析有着重要意义。 本文的主要研究内容是,利用台风实测数据,结合时频谱估计技术、非平稳时程模拟方法和有限元分析方法,探索进行台风非平稳激励下的悬索桥抖振响应时程分析方法。本文主要开展了以下几方面工作： 1、利用谐波合成法在Fortran90平台上编制常态平稳高斯风场模拟的程序,并利用FFT技术加速计算,对石登门悬索桥主梁45个节点进行平稳脉动风时程模拟。 2、利用希尔伯特-黄变换分析台风时程,揭示实测台风时程的时变特性。 3、用短时傅里叶变化估计实测台风数据的时频谱；利用实测台风的时变均值特性调制工程上常用的风速功率谱,经对比后选取Von-Karman谱作拟合时频谱；对比短时傅里叶变化估计的时频谱和Von-Karman拟合时频谱,结果显示二者结果十分吻合。 4、利用实测台风拟合时频谱在Fortran90平台编制一维n点非平稳脉动风时程的谐波合成法模拟程序；对石登门悬索桥主梁45个节点进行非平稳脉动风时程模拟。希尔伯特-黄变化对模拟的脉动风时程的分析显示,非平稳脉动风模拟时程比平稳脉动风模拟时程的前两阶模态瞬时频率随时间变化明显,具有非平稳特性。 5、基于大型通用有限软件ANSYS建立石登门悬索桥的空间有限元模型,并通过调整主缆初应变找到悬索桥的近似初状态,并据此进行石登门桥模态分析。 6、应用非平稳抖振时变方程的数值解法,在ANSYS上进行石登门悬索桥的非平稳和平稳激励下的时域抖振响应分析,结果显示非平稳激励下的桥梁主梁节点位移响应均方值大于平稳激励下的桥梁节点位移响应均方值,因此对桥梁结构进行更加精细化非平稳抖振分析有重要意义。
[Abstract]:Absrtact: with the in-depth understanding of the non-stationary characteristics of extreme wind (typhoon, downburst current, etc.) wind speed, and the development of long-span bridges towards lighter and softer directions, the flexible system bridges (suspension bridges) located in typhoon-prone areas, More and more attention has been paid to the aerodynamic stability of cable-stayed bridges under non-stationary excitation of typhoons. It is of great significance to study the buffeting response of bridges under the excitation of non-stationary pulsating wind by using the measured typhoon data, which is of great significance for the detailed buffeting analysis of bridges. The main content of this paper is to explore the time-history analysis method of buffeting response of suspension bridge under non-stationary excitation by using the measured data of typhoon, time spectrum estimation technique, non-stationary time-history simulation method and finite element analysis method. The main work of this paper is as follows: 1. The harmonic synthesis method is used to program the wind field simulation of normal stationary Gao Si on Fortran90 platform, and the FFT technique is used to accelerate the calculation. The stationary pulsating wind time history of 45 nodes of main girder of Shidengmen suspension bridge was simulated. 2. Using Hilbert-Huang transform to analyze typhoon time history, the time-varying characteristics of measured typhoon time history are revealed. (3) the time-frequency spectrum of the measured typhoon data is estimated by short-time Fourier transform, and the wind speed power spectrum is modulated by the time-varying mean characteristic of the measured typhoon, and the Von-Karman spectrum is selected as the fitting time spectrum after comparison. Comparing the time spectrum of short time Fourier transform estimation with that of Von-Karman fitting time spectrum, the results show that the two results are in good agreement with each other. 4. Using the measured typhoon fitting time spectrum in the Fortran90 platform, the harmonic synthesis simulation program of one-dimensional n-point non-stationary pulsating wind history is compiled, and the non-stationary pulsating wind time history simulation is carried out on 45 nodes of the main girder of the Shidengmen suspension bridge. The analysis of the simulated pulsating wind time history by Hilbert-Huang variation shows that the first two modes instantaneous frequency of the non-stationary pulsating wind simulation history is more obvious than that of the stationary pulsating wind simulation time history, and the transient frequency of the first two modes of the simulated time history of the non-stationary pulsating wind has the characteristics of non-stationary. 5. Based on ANSYS, a finite element model of the suspension bridge is established, and the approximate initial state of the suspension bridge is found by adjusting the initial strain of the main cable, and the modal analysis of the bridge is carried out. 6. The time-domain buffeting response analysis of a stone landing suspension bridge under non-stationary and stationary excitation is carried out on ANSYS by using the numerical solution of the non-stationary buffeting time-varying equation. The results show that the mean square value of the displacement response of the bridge main beam under non-stationary excitation is larger than that of the bridge node under the stationary excitation, so it is important to analyze the bridge structure with more detailed non-stationary buffeting.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3;U448.25
本文编号：2423133
[Abstract]:Absrtact: with the in-depth understanding of the non-stationary characteristics of extreme wind (typhoon, downburst current, etc.) wind speed, and the development of long-span bridges towards lighter and softer directions, the flexible system bridges (suspension bridges) located in typhoon-prone areas, More and more attention has been paid to the aerodynamic stability of cable-stayed bridges under non-stationary excitation of typhoons. It is of great significance to study the buffeting response of bridges under the excitation of non-stationary pulsating wind by using the measured typhoon data, which is of great significance for the detailed buffeting analysis of bridges. The main content of this paper is to explore the time-history analysis method of buffeting response of suspension bridge under non-stationary excitation by using the measured data of typhoon, time spectrum estimation technique, non-stationary time-history simulation method and finite element analysis method. The main work of this paper is as follows: 1. The harmonic synthesis method is used to program the wind field simulation of normal stationary Gao Si on Fortran90 platform, and the FFT technique is used to accelerate the calculation. The stationary pulsating wind time history of 45 nodes of main girder of Shidengmen suspension bridge was simulated. 2. Using Hilbert-Huang transform to analyze typhoon time history, the time-varying characteristics of measured typhoon time history are revealed. (3) the time-frequency spectrum of the measured typhoon data is estimated by short-time Fourier transform, and the wind speed power spectrum is modulated by the time-varying mean characteristic of the measured typhoon, and the Von-Karman spectrum is selected as the fitting time spectrum after comparison. Comparing the time spectrum of short time Fourier transform estimation with that of Von-Karman fitting time spectrum, the results show that the two results are in good agreement with each other. 4. Using the measured typhoon fitting time spectrum in the Fortran90 platform, the harmonic synthesis simulation program of one-dimensional n-point non-stationary pulsating wind history is compiled, and the non-stationary pulsating wind time history simulation is carried out on 45 nodes of the main girder of the Shidengmen suspension bridge. The analysis of the simulated pulsating wind time history by Hilbert-Huang variation shows that the first two modes instantaneous frequency of the non-stationary pulsating wind simulation history is more obvious than that of the stationary pulsating wind simulation time history, and the transient frequency of the first two modes of the simulated time history of the non-stationary pulsating wind has the characteristics of non-stationary. 5. Based on ANSYS, a finite element model of the suspension bridge is established, and the approximate initial state of the suspension bridge is found by adjusting the initial strain of the main cable, and the modal analysis of the bridge is carried out. 6. The time-domain buffeting response analysis of a stone landing suspension bridge under non-stationary and stationary excitation is carried out on ANSYS by using the numerical solution of the non-stationary buffeting time-varying equation. The results show that the mean square value of the displacement response of the bridge main beam under non-stationary excitation is larger than that of the bridge node under the stationary excitation, so it is important to analyze the bridge structure with more detailed non-stationary buffeting.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3;U448.25
【参考文献】
相关期刊论文 前2条
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