钢管混凝土拱桥K形节点力学性能有限元研究

发布时间：2018-02-20 08:05

本文关键词： 钢管混凝土拱桥 K形节点有限元数值模拟极限承载力　出处：《广西大学》2015年硕士论文　论文类型：学位论文

【摘要】：钢管混凝土K形节点是钢管混凝土拱桥的重要传力节点,理解和掌握节点的受力性能和破坏模式,有助于深化对钢管混凝土拱桥的认识和研究。本文根据节点的受力情况,主管受一定轴压力水平下,两支管分别受轴压和轴拉力,通过理论分析和有限元数值模拟分析对节点受力性能和破坏模式进行研究,主要的工作和结论为：(1)研究钢管混凝土拱桥K形节点有限元基本理论,选择合理的钢管和混凝土本构关系,提出合理有效的节点有限元建模方法,并对文献中的节点的构件进行有限元分析,通过与试验结果进行对比,分析得出文中的节点有限元建模方法是科学合理的。(2)对钢管混凝土拱桥K形节点和空钢管K形节点的荷载-位移曲线对比分析,研究节点的受力机理,主管有无混凝土有效的约束和支撑主管大大提高了节点的承载力和刚度；分析了节点荷载-位移关系曲线的特征,总体上可分为弹性阶段、弹塑性阶段和破坏阶段三个阶段,并探讨了这三个阶段节点的应力分布情况,得出节点的破坏模式：节点发生受压支管接头支管局部屈曲的破坏和节点发生受拉支管接头处主管扯裂的破坏。(3)通过ANSYS有限元建立构造参数不同的钢管混凝土拱桥K形节点模型,进行数值模拟分析,节点构造参数包括：支管径厚比γ、主管径厚比κ、支管与主管外径比w、支管与主管壁厚比ι、支管与主管轴线夹角θ、两支管间隙g、核心混凝土等级、主管轴压力水平n以及节点尺寸缩放系数ζ等,并对各设计参数取值作出规定。通过研究分析得出：支管与主管几何尺寸是影响节点极限承载力的主要因素,其他因素不同程度影响节点极限承载力,主管轴压力水平n为0.5～0.6时,节点极限承载力达到峰值。(4)在材料力学基本理论和矩形钢管混凝土节点承载力计算方法的基础上,推导出不同破坏模式下计算钢管混凝土拱桥K形节点在的极限承载力建议公式,并与有限元模拟计算值对比,误差较小且偏安全。
[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 纬, 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.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.22

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