五边形钢管混凝土翼缘组合梁整体稳定性能研究

发布时间：2018-04-07 18:58

本文选题：钢管混凝土翼缘　切入点：集中荷载　出处：《华中科技大学》2014年硕士论文

【摘要】：钢管混凝土结构因其结合了钢材和混凝土的优点被广泛应用于梁柱设计中，填充混凝土可以改善外钢管的局部稳定性、提高构件的整体稳定性和强度，而钢材给内填混凝土提供有效的约束作用，使混凝土处于复杂应力（三向应力）状态。如果传统I型梁的平板受压翼缘用钢管混凝土替换，则形成一种新型截面组合梁——钢管混凝土翼缘梁，与平板翼缘钢混形式的组合梁相比，该类梁具有更高的强度、刚度以及稳定性。目前对于该类型梁的相关试验及数值模拟研究较少，本文利用已有的试验数据，，对五边形钢管混凝土翼缘梁（CFPFB）在集中力作用下的整体稳定性能进行深入研究。主要内容如下：首先，利用有限元软件ANSYS建模，钢管采用SHELL181单元模拟，混凝土采用SOLID65单元模拟，并利用已有的试验数据对模型进行破坏模式、极限承载力、荷载-位移曲线等方面的验证，结果表明，有限元能较好的模拟CFPFB的受力性能。随后，对空翼缘梁以及CFPFB进行对比分析，结果表明内填混凝土可以增强翼缘的稳定性，增加翼缘的抗扭刚度和抗弯刚度。并研究CFPFB的五个重要几何参数（上翼缘含钢率(s)、腹板高厚比(f)、底部翼缘宽厚比(d)、跨高比(k)、五边形夹角(θ)）对整体稳定性能的影响，对提高构件的承载力提出合理的建议。基于能量法得出的弹性临界弯矩公式与出现整体失稳破坏的CFPFB弹性屈曲结果符合较好。通过分析中长跨和长跨CFPFB的荷载-应变曲线，用失稳极限、失稳发生以及初始屈服三种极限状态来定义不同跨度的CFPFB的侧向弯扭屈曲强度。最后，对整体稳定性能影响较大的四个参数s、f、d、k进行正交组合，建立192个模型，基于单参数分析的结果利用非线性拟合软件Datafit软件进行多元回归分析，得到集中荷载作用下的CFPFB整体稳定参数方程，有限元计算结果与试验结果的验证分析表明该参数方程有相对较高的精度和可靠度。
[Abstract]:Concrete-filled steel tube (CFST) structure is widely used in Liang Zhu design because of its advantages of combining steel and concrete. Filling concrete can improve the local stability of outer steel tube and enhance the overall stability and strength of members.Steel can effectively restrain the concrete and make the concrete in the state of complex stress (triaxial stress).If the flange of the traditional I-beam is replaced by concrete filled steel tube, a new type of composite beam-CFST flange beam is formed, which has higher strength than the composite beam with steel-concrete flange of flat flange.Stiffness and stability.At present, there are few experimental and numerical simulation studies on this type of beam. In this paper, the overall stability of CFPFB with pentagonal CFPFB under concentrated force is studied by using the existing experimental data.The main contents are as follows:Firstly, the finite element software ANSYS is used to model the model, the steel tube is simulated by SHELL181 element, and the concrete is simulated by SOLID65 element. The failure mode, ultimate bearing capacity and load-displacement curve of the model are verified by the existing test data.The results show that the finite element method can simulate the mechanical behavior of CFPFB.The results show that the stability of the flange can be enhanced and the torsional and flexural stiffness of the flange can be increased by the contrast analysis of the empty flange beam and CFPFB.The influence of five important geometric parameters of CFPFB (the steel content of upper flange, the ratio of web height to thickness), the ratio of width to thickness of bottom flange, the ratio of span to height, the angle of pentagonal angle (胃) to the overall stability performance are studied, and some reasonable suggestions for improving the bearing capacity of members are put forward.The formula of critical moment of elasticity based on energy method is in good agreement with the results of CFPFB elastic buckling with global instability.By analyzing the load-strain curves of CFPFB with medium long span and long span, the lateral bending and torsional buckling strength of CFPFB with different span is defined by three limit states: instability limit, instability occurrence and initial yield.Finally, the four parameters sffdnk, which have a great influence on the overall stability, are orthogonal combined, and 192 models are established. Based on the results of single parameter analysis, the multivariate regression analysis is carried out by using the nonlinear fitting software Datafit software.The global stability parameter equation of CFPFB under concentrated load is obtained. The results of finite element analysis and experimental results show that the parameter equation has relatively high accuracy and reliability.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU398.9

【相似文献】