型钢混凝土框架结构宏观有限元的方法研究

发布时间：2018-06-09 13:43

本文选题：型钢混凝土 + 框架结构　；参考：《西安建筑科技大学》2013年博士论文

【摘要】：型钢混凝土（SRC）组合结构以其刚度大、承载能力高、抗震性能优越等优点，成为高烈度设防地区高层、大跨、重载及高耸结构的首选结构形式。鉴于试验采集到的试验数据普遍存在较大离散性且在数量上不具备统计意义，现阶段采用理论分析和数值方法相结合对相关科学问题进行探究不失为一种可行的研究手段。考虑到基于微观单元的数值模拟建模过程较为复杂，加之计算成本较高且对计算机硬件有着高标准需求，难以对大型复杂结构非线性力学行为进行有限元数值分析。借助宏观单元的有限元数值模拟在确保计算精度的前提下可实现对计算成本的有效控制，得到了广大科研工作者的青睐。为满足SRC框架结构宏观力学行为研究的需要，论文基于纤维单元模型理论并结合课题组前期关于型钢-混凝土间粘结滑移性能试验研究成果，在纤维层面上通过修正钢纤维的应变以实现对材料间粘结滑移的数值体现，使其更为精确地反映构件强非线性力学行为，同时提出了模拟SRC节点剪切变形的剪切块模型，并结合现阶段最新2D单元理论，从而构建了SRC节点单元，最终基于OpenSEES软件平台建立了SRC框架宏观有限元计算模型，取得了理想的验证效果。主要研究内容及研究结论有： 1.分别采用宏观单元和微观单元对SRC柱抗震性能进行数值模拟分析，并结合试验实测数据，探讨了宏观单元和微观单元有限元数值模拟在单元原理、材料本构、网格划分、加载控制及模拟结果等方面的优缺点，提出了基于宏观单元的SRC梁-柱构件精细化建模方法，为深入进行SRC梁-柱宏观有限元理论研究奠定了基础。 2.本课题组前期的研究成果表明，SRC构件在粘结滑移发生后，，构件的承载力有较大改变。本文基于纤维单元模型理论，根据课题组前期提出的型钢-混凝土粘结滑移本构模型及粘结滑移沿截面高度的变化规律，提出在纤维层面上通过修正钢纤维应变的方法以实现对材料间粘结滑移的数值体现，该方法的意义在于精确的反映SRC构件非线性力学行为。 3.为洞悉SRC节点内部应力的传递模式与分布情况，通过辅以微观有限元模拟以弥补试验研究无法观察节点内部应力分布形态的不足，对SRC平面框架涉及的中节点、边节点、角节点及屋面中节点进行剪切变形分析，结果表明节点内部应力主要分布在节点核心区型钢腹板、型钢翼缘内部混凝土斜压短柱及核心区外箍筋约束的混凝土斜压短柱区域，为建立剪力传递公式提供了分析依据。 4.提出用于模拟SRC节点剪切变形的剪切块模型，并结合现阶段最新2D节点单元理论以构建SRC节点单元。根据SRC节点构造特点及内部应力传递模式与分布情况，认为SRC框架梁-柱节点剪力应由节点核心区型钢腹板、内部斜压杆及外部斜压杆三个部分承担，结合主要建筑材料的非线性本构模型，提出了SRC节点剪力传递公式，同时辅以试验得到的斜压杆宽度调整系数，最终建立了用于模拟SRC节点剪切变形的剪切块模型，随即利用C++计算机语言将剪切块模型编译为计算程序，以供2D节点单元程序调用，实现了SRC节点单元的数值体现。 5.将纤维单元精细化模拟SRC梁-柱构件的方法与SRC梁-柱节点单元相结合，基于OpenSEES软件平台建立SRC框架宏观有限元计算模型。试验结果与模拟结果对比表明，本方法建立的SRC框架模型较好的模拟了SRC框架循环荷载作用下的力学响应。
[Abstract]:The composite steel concrete (SRC) composite structure has become the first structure of high level, large span, heavy load and high towering structure in high intensity fortification area with its advantages of large stiffness, high bearing capacity and superior seismic performance. In view of the large discreteness and no statistical significance in the experimental data collected by the test, the theory is adopted at the present stage. The combination of analysis and numerical methods is a feasible research method. Considering the complexity of the modeling process of numerical simulation based on the microelement, and the high cost of calculation and high standard of computer hardware, it is difficult to carry out the finite element analysis of the nonlinear mechanical behavior of large complex structures. With the help of the finite element numerical simulation of the macro element, the effective control of the calculation cost can be realized on the premise of ensuring the calculation precision.
In order to meet the needs of macro mechanical behavior research of SRC frame structure, the paper based on the theory of fiber element model and combined with the previous research results of the experimental study on the bond slip behavior between steel and concrete in the project group, and by modifying the strain of steel fiber at the fiber level, the numerical expression of the bond slip between the materials is realized, so that it is more accurate. It reflects the strong nonlinear mechanical behavior of the component. At the same time, the shear block model is proposed to simulate the shear deformation of the SRC node. The SRC node unit is constructed with the latest 2D element theory at the present stage. Finally, the macro finite element calculation model of the SRC frame is established based on the OpenSEES software platform, and the ideal results are obtained. The main research content and the main research content are obtained. The conclusions are as follows:
1. the seismic performance of SRC column is numerically simulated by macro element and microelement, and combined with the experimental data, the advantages and disadvantages of the element principle, material constitutive, mesh division, loading control and simulation results are discussed, and the SRC beam based on macro element is proposed. The detailed modeling method for column members lays a foundation for further research on SRC beam column macro finite element theory.
2. the previous research results of the project group show that the bearing capacity of the component is greatly changed after the bond slip occurs in the SRC component. Based on the theory of fiber element model, this paper proposes the modification of the bond slip constitutive model and the change law of the bond slip along the height of the cross section. The method of steel fiber strain is used to realize the numerical expression of bond slip between materials. The significance of this method is to accurately reflect the nonlinear mechanical behavior of SRC components.
3. in order to understand the transmission mode and distribution of the internal stress in the SRC node, by using the microscopic finite element simulation to make up for the inability to observe the stress distribution in the node, the shear deformation analysis of the middle nodes, side nodes, corner nodes and the joints in the roof of the SRC plane frame is analyzed. The results show the internal stress of the node. It is mainly distributed in the core zone type steel web, the concrete baroclinic short column inside the steel flange and the concrete baroclinic short column confined by the outer stirrup in the core area, which provides the basis for the establishment of shear transfer formula.
4. the shear block model used to simulate the shear deformation of SRC nodes is proposed, and the latest 2D node element theory is combined with the present stage to construct the SRC node unit. According to the structural characteristics of the SRC node and the internal stress transmission mode and distribution, it is believed that the shear of the beam column joint of the SRC frame should be composed of the core section steel web, the internal baroclinic bar and the external baroclinic pressure. In connection with the three parts of the bar, combining the nonlinear constitutive model of the main building material, the shear transfer formula of SRC node is proposed. At the same time, the shear block model used to simulate the shear deformation of the SRC node is established, and the shear block model is finally established to simulate the shear deformation of the barotropic bar. Then the shear block model is compiled into a computing program by using the C++ computer language. In order to invoke the 2D node unit program, the SRC node unit is reflected numerically.
5. the method of finely simulating the SRC beam column component with the fiber element is combined with the SRC beam column node element, and the macro finite element calculation model of the SRC frame is established based on the OpenSEES software platform. The test results and the simulation results show that the SRC frame model established by this method is better to simulate the mechanical response of the SRC frame under cyclic loading.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU398.9

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