钢筋混凝土框架结构非线性性能的离散元分析

发布时间：2018-07-12 20:55

本文选题：钢筋混凝土 + 框架结构　；参考：《沈阳建筑大学》2014年硕士论文

【摘要】：地震作用下结构非线性反应与倒塌破坏的研究是结构工程学科的一项重要课题,也是目前的研究热点之一。尽管国内外学者们已对此提出了一些数值分析方法,但这些方法仍难以较好地对结构进行从弹性到塑性、从小变形到大变形直至倒塌塌落的全过程分析。作为一种非连续性的数值分析方法,离散单元法不要求单元之间位移协调,适用于结构倒塌破坏中的位移场不连续、接触碰撞以及大位移、大转动等问题的求解。离散单元法首先是在岩土工程领域发展起来的,目前已逐步用于结构的非线性地震反应与倒塌破坏机理分析研究。而以往的离散单元计算模型由于模型中的本构关系没有明确的物理意义且单元数目巨大,很难用于大型复杂结构的倒塌破坏分析,特别是以往方法对于结构倒塌前的非线性性能模拟的准确性尚需进一步进行研究。本文主要对离散单元法在钢筋混凝土框架结构的非线性分析中的应用进行研究,具体工作如下：1.在查阅大量国内外文献的基础上,对结构非线性与倒塌分析的数值分析方法,尤其是离散单元法在结构工程领域的研究现状进行了总结、评述。并对基于离散单元法提出的杆段多弹簧模型作了改进研究,通过在弹簧组中添加扭转弹簧来满足构件的多向加载以及模拟构件扭转性能的需求。2.运用杆段多弹簧模型以及本文SMS-Collapse程序,对低周往复加载下钢筋混凝土柱的受力行为进行了数值模拟,并与试验结果及有限元模拟结果进行了对比研究。分析结果表明,杆段多弹簧模型能够准确描述混凝土梁柱构件的轴力-弯矩耦合效应,并可细致描述截面材料的力学行为发展历程。本文模型能够较准确地描述钢筋混凝土梁柱构件在低周往复荷载下的非线性滞回行为。3.对低周反复水平荷载作用下的钢筋混凝土平面框架进行了数值模拟,计算结果与试验结果吻合良好。说明本文所建立的结构计算分析模型是合理的,SMS-Collapse程序可以真实、正确描述结构的反应,能适用于整体结构的非线性分析,并具有较高的精度。4.对钢筋混凝土框架结构非线性反应与倒塌仿真分析程序SMS-Collapse进行二次开发。采用FORTRAN语言对本程序前处理模块进行改进,添加了前处理模型INPUT文本输出、自定义材料子程序接口两个模块,用户能够在INPUT文本中直接修改模型参数并且调用已有的单轴材料本构模型,大大提高了程序的通用性和可拓展性。5.对离散单元法中的结构静力算法进行改进,通过采用准静态加载方法来降低惯性力效应对结构静力加载的影响。准静态加载方法在处理非线性问题时无需迭代求解,与以往的迭代算法相比,在保证计算精度的前提下大大降低了计算工作量。
[Abstract]:The study of nonlinear response and collapse failure of structures under earthquake action is an important subject in the field of structural engineering, and is also one of the research hotspots at present. Although scholars at home and abroad have put forward some numerical analysis methods, it is still difficult to analyze the whole process of structure from elasticity to plasticity, from small deformation to large deformation to collapse and collapse. As a discontinuous numerical analysis method, the discrete element method does not require the coordination of displacement between the elements, and is suitable for the solution of discontinuous displacement field, contact collision, large displacement and large rotation in the collapse and failure of structures. The discrete element method has been developed in the field of geotechnical engineering and has been applied to the analysis and study of nonlinear seismic response and collapse failure mechanism of structures. However, the previous discrete element calculation model is difficult to be used to analyze the collapse failure of large and complex structures because the constitutive relation in the model has no explicit physical meaning and the number of elements is huge. In particular, the accuracy of the nonlinear performance simulation before the collapse of the structure by the previous methods needs to be further studied. In this paper, the application of discrete element method in nonlinear analysis of reinforced concrete frame structures is studied. The specific work is as follows: 1. On the basis of consulting a large number of literatures at home and abroad, the numerical analysis methods of nonlinear and collapse analysis of structures, especially the research status of discrete element method in the field of structural engineering, are summarized and reviewed. An improved multi-spring model based on discrete element method is proposed. The torsion spring is added to the spring group to meet the requirements of multi-direction loading and torsional performance simulation. By using the multi-spring model and SMS-Collapse program, the behavior of reinforced concrete columns under low-cycle reciprocating loading is numerically simulated and compared with the experimental results and finite element simulation results. The results show that the multi-spring model can accurately describe the coupling effect of axial force and bending moment of concrete Liang Zhu members, and can be used to describe the development of mechanical behavior of cross-section materials in detail. The model in this paper can accurately describe the nonlinear hysteretic behavior of reinforced concrete Liang Zhu members under low cycle reciprocating loads. The numerical simulation of reinforced concrete plane frame under low cyclic horizontal load is carried out, and the calculated results are in good agreement with the experimental results. It is shown that the structural calculation and analysis model established in this paper is reasonable, and the SMS-Collapse program can describe the response of the structure correctly, and it can be applied to the nonlinear analysis of the whole structure, and has a higher accuracy. The simulation program SMS-Collapse for nonlinear response and collapse of reinforced concrete frame structures is developed. The preprocessing module of this program is improved by FORTRAN language. Two modules are added: input text output of pre-processing model and interface of self-defined material subroutine. The user can modify the model parameters directly in input text and call the existing uniaxial material constitutive model, which greatly improves the generality and expansibility of the program. The structure static method in discrete element method is improved, and the quasi-static loading method is adopted to reduce the influence of inertial force effect on the static loading of the structure. The quasi-static loading method does not need to be solved iteratively when dealing with nonlinear problems. Compared with the previous iterative algorithms, the computational workload is greatly reduced under the premise of ensuring the accuracy of the calculation.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.4

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