碳纤维加固钢筋混凝土梁非线性有限元分析

【作者】 赵建立；

【导师】 张雷顺； 郭进军；

【作者基本信息】 郑州大学 ， 水工结构， 2004， 硕士

【摘要】 本文首先综述了到目前为止国内外的钢筋混凝土非线性有限元分析的研究成果，对组成钢筋混凝土结构的两种材料-钢筋和混凝土本构关系做了详细的阐述。 在非线性有限元分析理论的基础上，设计了用于碳纤维布加固的钢筋混凝土梁有限元分析程序。所编制的程序具有以下主要特点： 1、程序中共使用了四种单元形式：混凝土三角形单元、钢筋线单元、加固层线单元和双弹簧粘结单元； 2、模拟了混凝土单元开裂、钢筋屈服造成的应力重分布现象； 3、模拟了主裂缝产生对破坏荷载的影响； 4、考虑了开裂混凝土单元的咬合作用； 5、对不平衡结点荷载的移置使用了各种计算方法，并对计算结果进行对比； 6、通过改变程序的个别参数，可以对使用其它方法加固的梁进行模拟计算； 7、程序的兼容性较好，可在各种计算机上进行快速计算； 8、程序的二次开发性较高，通过对程序的进一步开发，可形成一个较大型的软件系统，对常见的混凝土构件进行分析计算。 考虑到国内外编制碳纤维布加固有限元分析程序不多的特点，在编制程序的基础上，本文还做了以下主要工作： 1、对程序计算结果与试验结果进行对比，验证了程序的可行性和适用性； 2、探讨了如何将开裂混凝土单元的不平衡结点荷载向钢筋和碳纤维布分配的问题，提出了“分配比例”的概念，并给出了计算公式； 3、根据参考文献中有关主裂缝间距的计算公式，探讨了程序实现的方法； 4、通过程序计算和理论分析发现，混凝土单元开裂后，由于混凝土之间的咬合作用，需要将其产生的15％-20％左右的不平衡结点荷载移置到结构中； 5、对碳纤维布加固钢筋混凝土梁还做了两个系列的扩展计算，一个是碳纤维布厚度对结构破坏荷载的影响：另一个是混凝土的强度等级对结构破坏荷载的影响，根据计算结果提出了一些合理的建议。 另外，本文还为今后本课题的进一步研究提供了思路和方向。更多还原

【Abstract】 At first, this paper summarizes recent efforts in finite element analysis of reinforced concrete structures in the world. The constitutive models of steel and concrete are carefully said, which are basic materials of reinforced concrete.And on the base of theory of non-linear finite element analysis, the paper designed a program, which can be used to analyze CFRP strengthened reinforced concrete beams. The program has some main traits:1. It used four elements: concrete triangle element, steel linear element, CFRP linear element, double-spring element;2. It can simulate the phenomena of distribution stress again when the concrete element ripped or the steel bent;3. It simulates the effect of main crack to limit flexural loading;4. It takes into account of friction among ripped concrete elements;5. It used several kinds of methods to distribute the imbalance node loading, and contrast them;6. By changing some parameter of program, it can calculate other strengthening method;7. The compatibility of program is better, and it can be used on all kinds of computers;8. The exploitation of program is so good that it can be designed more and a software system can come into being on base of it.Considering there are not many programs about CFRP strengthened beams in the world so far, on the basis of the program the paper also did the following work:1. The program results is contrasted with experimental results, and the compatibility is well, which proves that the program designed by author is accurate and reliable enough;2. The paper discussed the problem that how to distribute the imbalance node loading to steel and CFRP When concrete element is ripped, and put forward the formula of distribution proportion;3. According to the formula of space between main cracks, the paperdiscussed the achievement method in program;4. The paper found that because of friction among ripped concrete elements, 15%-20% of imbalance node loading must be moved to the structure;5. The paper calculated two series of CFRP strengthened reinforced concrete beams. One is the effect of thickness CFRP to limit flexural loading; the other is the effect of concrete grade to limit flexural loading. The paper also put forward some reasonable advice by calculation.Additionally, this paper also presents a way and direction for the further study on this problem in future.更多还原