【摘要】：隨著橋梁工程設(shè)計和施工技術(shù)的不斷發(fā)展,大跨度斜拉橋不斷涌現(xiàn),斜拉橋結(jié)構(gòu)的剛度變得越來越柔,對風(fēng)和地震為主的動力荷載作用十分敏感。因此對斜拉橋的結(jié)構(gòu)健康監(jiān)測及損傷識別等的要求不斷提高,必須建立一個能全面準(zhǔn)確地反映大跨度斜拉橋的真實性態(tài)的有限元模型,用于其結(jié)構(gòu)健康監(jiān)測狀態(tài)的有效評估。為此以大跨度橋梁的靜動力實測結(jié)果為依據(jù),對大跨度斜拉橋初始有限元模型進(jìn)行模型修正,保證計算結(jié)果與實測的結(jié)果基本吻合,在此基礎(chǔ)上建立適用于大跨度斜拉橋長期健康監(jiān)測的基準(zhǔn)有限元模型。本文以廣州鶴洞大橋長期結(jié)構(gòu)健康監(jiān)測為背景,采用基于時、頻域的系統(tǒng)參數(shù)辨識方法,對大跨度斜拉橋的拉索索力和實測加速度信號進(jìn)行信號分析,獲得斜拉橋預(yù)拉力及主體結(jié)構(gòu)相關(guān)的結(jié)構(gòu)動力特征參數(shù);探索了利用大型通用有限元SAP2000應(yīng)用程序接口(API)的Matlab開發(fā)環(huán)境,進(jìn)行后續(xù)有限元模型修正等方面的研究。為此本文主要展開了以下幾個方面的工作:首先利用廣州鶴洞大橋長期結(jié)構(gòu)健康監(jiān)測數(shù)據(jù),分析了斜拉索的索力、橋面振動特性。建立了識別拉索基頻辨識的MATLAB工具箱,運用自互譜法、隨機子空間法及無線監(jiān)測系統(tǒng)對橋面振動特性進(jìn)行了分析。獲得了現(xiàn)階段廣州鶴洞大橋的部分索力及前幾階振型的實測動力特征(固有頻率、振型、阻尼),并將時域與頻域法識別結(jié)果進(jìn)行了對比,最后還與ARTeMIS軟件分析結(jié)果進(jìn)行了校核。參照廣州鶴洞大橋工程設(shè)計施工圖紙,截面物理屬性,建立了與其對應(yīng)的SAP2000初始有限元模型,通過反復(fù)調(diào)整模型參數(shù),直至使得初始模型在恒載和索力作用下橋面線型與該橋的成橋線型,計算索力與實測索力基本吻合,在此基礎(chǔ)上建立了大跨度斜拉橋基于索力測試的鶴洞大橋初始修正模型。對鶴洞大橋初始修正模型進(jìn)行了模態(tài)分析,得出了其前20階振型的自振頻率及三維振型圖;分析了不同參數(shù)(斜拉索的不同類型有限元單元模擬、彈性模量、邊界條件及邊墩等)對大跨度斜拉橋結(jié)構(gòu)動力特征的影響。得出影響結(jié)構(gòu)動力特性的幾個重要參數(shù),為大型斜拉橋有限元模型修正的目標(biāo)函數(shù)、靈敏度分析研究提供了依據(jù)。最后將有限元分析結(jié)果與實測結(jié)果進(jìn)行了對比,初步得到用于廣州鶴洞大橋結(jié)構(gòu)健康監(jiān)測的基準(zhǔn)有限元模型;并利用結(jié)構(gòu)參數(shù)識別系統(tǒng)PARIS,結(jié)合其對UFC橋梁有限元模型修正的相關(guān)分析結(jié)果,探討了有限元模型修正理論,采用敏感度分析和結(jié)構(gòu)優(yōu)化理論,研究廣州鶴洞大橋結(jié)構(gòu)健康監(jiān)測基準(zhǔn)有限元模型修正中的潛在應(yīng)用。
[Abstract]:With the continuous development of bridge engineering design and construction technology, long-span cable-stayed bridges are emerging, and the stiffness of cable-stayed bridges becomes more and more flexible, which is very sensitive to the dynamic loads of wind and earthquake. Therefore, the requirements for structural health monitoring and damage identification of cable-stayed bridges are constantly raised, so it is necessary to establish a finite element model which can fully and accurately reflect the authenticity of long-span cable-stayed bridges and be used to effectively evaluate the structural health monitoring state of cable-stayed bridges. Based on the static and dynamic test results of long-span bridges, the initial finite element model of long-span cable-stayed bridges is modified to ensure that the calculated results are in good agreement with the measured results. On this basis, a benchmark finite element model for long term health monitoring of long span cable-stayed bridges is established. Based on the long term structural health monitoring of Guangzhou Hedong Bridge, the system parameter identification method based on time-frequency domain is used to analyze the cable force and the measured acceleration signal of the long-span cable-stayed bridge. The structural dynamic characteristic parameters related to the pretension force and the main structure of the cable-stayed bridge are obtained. The Matlab development environment of large universal finite element SAP2000 application interface (API) and the following finite element model modification are explored in this paper. The main work of this paper is as follows: firstly, the cable force and the vibration characteristics of the bridge deck are analyzed by using the long-term structural health monitoring data of Guangzhou Hedong Bridge. A MATLAB toolbox is established to identify the fundamental frequency of the cables. The vibration characteristics of the bridge deck are analyzed by using the self-cross spectrum method, the random subspace method and the wireless monitoring system. In this paper, some cable forces of Guangzhou Hedong Bridge and the measured dynamic characteristics (natural frequency, mode shape, damping) of the first few modes are obtained, and the identification results of time domain method and frequency domain method are compared. Finally, the results are checked with ARTeMIS software. Referring to the engineering design and construction drawings of Guangzhou Hedong Bridge and the physical properties of the section, the corresponding initial finite element model of SAP2000 is established, and the parameters of the model are adjusted repeatedly. Until the initial model is subjected to dead load and cable force, the initial modified model of Hedong Bridge based on cable force test is established. The modal analysis of the initial modified model of Hedong Bridge is carried out, and the natural frequency and three dimensional mode diagram of the first 20 modes are obtained. The influence of different parameters (finite element simulation of cable, elastic modulus, boundary condition and side pier etc.) on the dynamic characteristics of long-span cable-stayed bridge is analyzed. Several important parameters affecting the dynamic characteristics of the structure are obtained, which provide a basis for the objective function and sensitivity analysis of the finite element model modification of the large cable-stayed bridge. Finally, the results of finite element analysis are compared with the measured results, and the benchmark finite element model for structural health monitoring of Guangzhou Hedong Bridge is preliminarily obtained. Using the structural parameter identification system (PARIS,) combined with the related analysis results of the UFC bridge finite element model correction, the finite element model modification theory is discussed, and the sensitivity analysis and the structure optimization theory are adopted. The potential application of structural health monitoring benchmark finite element model modification of Guangzhou Hedong Bridge is studied.
【學(xué)位授予單位】：廣州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U446

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本文編號：2405046