臺風(fēng)非平穩(wěn)激勵(lì)下的懸索橋時(shí)域抖振分析
發(fā)布時(shí)間：2019-02-15 08:06
【摘要】：摘要：隨著對極端風(fēng)(臺風(fēng)、下?lián)舯┝鞯?風(fēng)速時(shí)程非平穩(wěn)特性的深入了解,以及大跨度橋梁朝著更輕、更柔的方向發(fā)展,位于臺風(fēng)多發(fā)地帶的柔性體系橋梁(懸索橋,斜拉橋)在臺風(fēng)非平穩(wěn)激勵(lì)下的氣動(dòng)穩(wěn)定性研究越來越受到重視。探索利用實(shí)測臺風(fēng)數(shù)據(jù)進(jìn)行臺風(fēng)非平穩(wěn)脈動(dòng)風(fēng)激勵(lì)下的橋梁抖振響應(yīng)的研究方法,對于進(jìn)行橋梁精細(xì)化抖振分析有著重要意義。 本文的主要研究內(nèi)容是,利用臺風(fēng)實(shí)測數(shù)據(jù),結(jié)合時(shí)頻譜估計(jì)技術(shù)、非平穩(wěn)時(shí)程模擬方法和有限元分析方法,探索進(jìn)行臺風(fēng)非平穩(wěn)激勵(lì)下的懸索橋抖振響應(yīng)時(shí)程分析方法。本文主要開展了以下幾方面工作： 1、利用諧波合成法在Fortran90平臺上編制常態(tài)平穩(wěn)高斯風(fēng)場模擬的程序,并利用FFT技術(shù)加速計(jì)算,對石登門懸索橋主梁45個(gè)節(jié)點(diǎn)進(jìn)行平穩(wěn)脈動(dòng)風(fēng)時(shí)程模擬。 2、利用希爾伯特-黃變換分析臺風(fēng)時(shí)程,揭示實(shí)測臺風(fēng)時(shí)程的時(shí)變特性。 3、用短時(shí)傅里葉變化估計(jì)實(shí)測臺風(fēng)數(shù)據(jù)的時(shí)頻譜；利用實(shí)測臺風(fēng)的時(shí)變均值特性調(diào)制工程上常用的風(fēng)速功率譜,經(jīng)對比后選取Von-Karman譜作擬合時(shí)頻譜；對比短時(shí)傅里葉變化估計(jì)的時(shí)頻譜和Von-Karman擬合時(shí)頻譜,結(jié)果顯示二者結(jié)果十分吻合。 4、利用實(shí)測臺風(fēng)擬合時(shí)頻譜在Fortran90平臺編制一維n點(diǎn)非平穩(wěn)脈動(dòng)風(fēng)時(shí)程的諧波合成法模擬程序；對石登門懸索橋主梁45個(gè)節(jié)點(diǎn)進(jìn)行非平穩(wěn)脈動(dòng)風(fēng)時(shí)程模擬。希爾伯特-黃變化對模擬的脈動(dòng)風(fēng)時(shí)程的分析顯示,非平穩(wěn)脈動(dòng)風(fēng)模擬時(shí)程比平穩(wěn)脈動(dòng)風(fēng)模擬時(shí)程的前兩階模態(tài)瞬時(shí)頻率隨時(shí)間變化明顯,具有非平穩(wěn)特性。 5、基于大型通用有限軟件ANSYS建立石登門懸索橋的空間有限元模型,并通過調(diào)整主纜初應(yīng)變找到懸索橋的近似初狀態(tài),并據(jù)此進(jìn)行石登門橋模態(tài)分析。 6、應(yīng)用非平穩(wěn)抖振時(shí)變方程的數(shù)值解法,在ANSYS上進(jìn)行石登門懸索橋的非平穩(wěn)和平穩(wěn)激勵(lì)下的時(shí)域抖振響應(yīng)分析,結(jié)果顯示非平穩(wěn)激勵(lì)下的橋梁主梁節(jié)點(diǎn)位移響應(yīng)均方值大于平穩(wěn)激勵(lì)下的橋梁節(jié)點(diǎn)位移響應(yīng)均方值,因此對橋梁結(jié)構(gòu)進(jìn)行更加精細(xì)化非平穩(wěn)抖振分析有重要意義。
[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.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441.3;U448.25
本文編號：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.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441.3;U448.25
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2 李錦華;李春祥;;土木工程隨機(jī)風(fēng)場數(shù)值模擬研究的進(jìn)展[J];振動(dòng)與沖擊;2008年09期
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