【摘要】：隨著我國大跨徑橋梁的迅速發(fā)展,扁平鋼箱梁的應(yīng)用越來越廣泛,其局部穩(wěn)定問題日益突出,本文在總結(jié)中外學(xué)者研究成果的基礎(chǔ)上,對扁平鋼箱梁進行局部穩(wěn)定研究,主要做了以下工作：(1)介紹了斜拉橋發(fā)展歷程及現(xiàn)狀；分析了扁平鋼箱梁的構(gòu)造和力學(xué)特性：對橋梁結(jié)構(gòu)的穩(wěn)定問題、局部穩(wěn)定理論進行了概述；(2)研究了四邊簡支板的屈曲臨界應(yīng)力的理論解,然后用Timoshenko法(能量法)和比擬正交異性板法(靜力法)推導(dǎo)了加勁板的屈曲臨界應(yīng)力理論解；(3)介紹了幾何非線性的成因及其類型,用ANSYS建立了薄板、開口及閉口加勁板的有限元模型,分析了幾何非線性對其承載力的影響,得到了荷載與位移曲線圖。(4)用ANSYS建立了薄板、開口及閉口肋加勁板有限元模型,對它們進行了屈曲分析,得到了第一階屈曲系數(shù)和屈曲應(yīng)力及屈曲時的變形形態(tài),分析了影響加勁板屈曲的因素,即板厚、肋條間距及剛度、橫隔板的間距,在分析的基礎(chǔ)上得出了各因素對加勁板屈曲影響的規(guī)律。(5)對工程背景中的扁平鋼箱梁進行了有限元模型分析,可知整個梁段在進行屈曲分析時橫隔板最先發(fā)生屈曲。(6)概述了肋條剛度對加勁板的影響,提出合理剛度比的概念,分析了加勁板的肋條和母板同時局部屈曲時所要剛度比的規(guī)律。
[Abstract]:With the rapid development of long-span bridges in China, the application of flat steel box girder is becoming more and more extensive, and the problem of local stability is becoming more and more prominent. In this paper, the local stability of flat steel box girder is studied on the basis of summing up the research results of Chinese and foreign scholars. The main work is as follows: (1) the development history and current situation of cable-stayed bridge are introduced; The structural and mechanical properties of flat steel box girder are analyzed. The stability problem of bridge structure and the theory of local stability are summarized. (2) the theoretical solution of buckling critical stress of simply supported plates with four edges is studied, and the theoretical solution of buckling critical stress of stiffened plates is derived by using Timoshenko method (energy method) and analogy orthotropic plate method (static method). (3) the causes and types of geometric nonlinearity are introduced. The finite element model of thin plate, open and closed stiffened plate is established by ANSYS, and the influence of geometric nonlinearity on its bearing capacity is analyzed. The curves of load and displacement are obtained. (4) the finite element model of thin plate, open and closed rib stiffened plate is established by ANSYS, and their buckling analysis is carried out, and the first order buckling coefficient, buckling stress and deformation pattern during buckling are obtained. The factors affecting buckling of stiffened plate are analyzed, such as thickness of plate, spacing and stiffness of ribs, and spacing of transverse partition. On the basis of analysis, the influence of various factors on buckling of stiffened plate is obtained. (5) finite element model analysis of flat steel box girder in engineering background is carried out. It can be seen that the first buckling occurs in the whole beam section when the transverse diaphragm is buckled. (6) the influence of rib stiffness on stiffened plate is summarized, and the concept of reasonable stiffness ratio is proposed. The stiffness ratio of stiffened plate is analyzed when the rib and the motherboard are buckled at the same time.
【學(xué)位授予單位】：長沙理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U441;U448.27
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本文編號：2428081