發(fā)布時(shí)間：2018-02-20 08:05

  本文關(guān)鍵詞： 鋼管混凝土拱橋 K形節(jié)點(diǎn) 有限元 數(shù)值模擬 極限承載力　出處：《廣西大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：鋼管混凝土K形節(jié)點(diǎn)是鋼管混凝土拱橋的重要傳力節(jié)點(diǎn),理解和掌握節(jié)點(diǎn)的受力性能和破壞模式,有助于深化對鋼管混凝土拱橋的認(rèn)識和研究。本文根據(jù)節(jié)點(diǎn)的受力情況,主管受一定軸壓力水平下,兩支管分別受軸壓和軸拉力,通過理論分析和有限元數(shù)值模擬分析對節(jié)點(diǎn)受力性能和破壞模式進(jìn)行研究,主要的工作和結(jié)論為：(1)研究鋼管混凝土拱橋K形節(jié)點(diǎn)有限元基本理論,選擇合理的鋼管和混凝土本構(gòu)關(guān)系,提出合理有效的節(jié)點(diǎn)有限元建模方法,并對文獻(xiàn)中的節(jié)點(diǎn)的構(gòu)件進(jìn)行有限元分析,通過與試驗(yàn)結(jié)果進(jìn)行對比,分析得出文中的節(jié)點(diǎn)有限元建模方法是科學(xué)合理的。(2)對鋼管混凝土拱橋K形節(jié)點(diǎn)和空鋼管K形節(jié)點(diǎn)的荷載-位移曲線對比分析,研究節(jié)點(diǎn)的受力機(jī)理,主管有無混凝土有效的約束和支撐主管大大提高了節(jié)點(diǎn)的承載力和剛度；分析了節(jié)點(diǎn)荷載-位移關(guān)系曲線的特征,總體上可分為彈性階段、彈塑性階段和破壞階段三個階段,并探討了這三個階段節(jié)點(diǎn)的應(yīng)力分布情況,得出節(jié)點(diǎn)的破壞模式：節(jié)點(diǎn)發(fā)生受壓支管接頭支管局部屈曲的破壞和節(jié)點(diǎn)發(fā)生受拉支管接頭處主管扯裂的破壞。(3)通過ANSYS有限元建立構(gòu)造參數(shù)不同的鋼管混凝土拱橋K形節(jié)點(diǎn)模型,進(jìn)行數(shù)值模擬分析,節(jié)點(diǎn)構(gòu)造參數(shù)包括：支管徑厚比γ、主管徑厚比κ、支管與主管外徑比w、支管與主管壁厚比ι、支管與主管軸線夾角θ、兩支管間隙g、核心混凝土等級、主管軸壓力水平n以及節(jié)點(diǎn)尺寸縮放系數(shù)ζ等,并對各設(shè)計(jì)參數(shù)取值作出規(guī)定。通過研究分析得出：支管與主管幾何尺寸是影響節(jié)點(diǎn)極限承載力的主要因素,其他因素不同程度影響節(jié)點(diǎn)極限承載力,主管軸壓力水平n為0.5～0.6時(shí),節(jié)點(diǎn)極限承載力達(dá)到峰值。(4)在材料力學(xué)基本理論和矩形鋼管混凝土節(jié)點(diǎn)承載力計(jì)算方法的基礎(chǔ)上,推導(dǎo)出不同破壞模式下計(jì)算鋼管混凝土拱橋K形節(jié)點(diǎn)在的極限承載力建議公式,并與有限元模擬計(jì)算值對比,誤差較小且偏安全。
[Abstract]:Concrete-filled steel tubular (CFST) K-shaped joint is an important force transfer node of CFST arch bridge. Understanding and mastering the mechanical behavior and failure mode of the joints is helpful to deepen the understanding and research of CFST arch bridge. Under a certain axial pressure level, two branch pipes are subjected to axial compression and axial tension respectively. The mechanical behavior and failure mode of the joints are studied by theoretical analysis and finite element numerical simulation. The main work and conclusions are as follows: (1) the basic theory of finite element method for K-joints of concrete-filled steel tubular arch bridge is studied, and the reasonable constitutive relation between steel tube and concrete is selected, and a reasonable and effective finite element modeling method for joints is proposed. The finite element analysis of the joints in the literature is carried out, and the results are compared with the experimental results. It is concluded that the finite element modeling method of joints in this paper is scientific and reasonable. The load-displacement curves of K-joints and empty steel tubes of concrete-filled steel tubular arch bridges are compared and analyzed, and the stress mechanism of the joints is studied. The bearing capacity and stiffness of joints are greatly improved by the effective restraint and bracing of concrete, and the characteristics of load-displacement curve of joints are analyzed, which can be divided into three stages: elastic stage, elastic-plastic stage and failure stage. The stress distribution of the joints in these three stages is also discussed. The failure mode of joint is obtained: the local buckling failure of the joint under pressure branch joint and the fracture of the joint in charge of tension branch joint. 3) the concrete filled steel tube arch with different structural parameters is established by ANSYS finite element method. Bridge K-node model, Numerical simulation analysis shows that the node construction parameters include: diameter to thickness ratio 緯, diameter to thickness ratio 魏, external diameter ratio of branch to supervisor, wall thickness ratio of branch to supervisor, angle 胃 between branch pipe and supervisor axis, gap between two branch pipes, and grade of core concrete. The axial pressure level n and the dimension scaling coefficient 味 of the joint are determined, and the values of the design parameters are defined. Through the research and analysis, it is concluded that the main factors affecting the ultimate bearing capacity of the joints are the geometry dimensions of the branch pipes and the superintendents. Other factors affect the ultimate bearing capacity of joints in varying degrees. When the axial pressure level n is 0.5 ~ 0.6, the ultimate bearing capacity of joints reaches the peak value. 4) on the basis of the basic theory of mechanics of materials and the calculation method of bearing capacity of concrete filled rectangular steel tube joints, The suggested formulas for calculating the ultimate bearing capacity of K-joints of concrete-filled steel tubular arch bridges under different failure modes are derived and compared with the calculated values of finite element simulation.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U441;U448.22

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本文編號：1519162