Development of Finite Element Method Program for the Analysis of Shear Failure of R.C.Structures.

本课题的目的是开发一个非线性有限元计算程序，用于预测钢筋混凝土结构由于少量斜向裂缝的发展而发生剪切破坏时的力学性能，本论文从混凝土的本构关系、裂缝模型以及混凝土与钢筋之间的粘结滑移等方面对应采用何种数学模型进行了数值研究。通过对分析结果和实验结果的对比研究，确定了目前最佳的分析条件组合为：1.采用不连续旋转裂纹模型，其中极限旋转角是裂纹宽度的函数.对于受压和受拉的混凝土，使用基于断裂能确定的软化曲线。作为元素的等效长度，使用相贯线的长度。3.考虑由于垂直方向的拉应变引起的混凝土抗压强度的降低。考虑混凝土与钢筋之间的粘结滑移。

The aim of this project is to develop a non-linear finite element method computer program, which is able to predict the mechanical behavior of RC structures failing in shear due to the development of few dominant diagonal cracks.In this accademic year, numerical study has done on what types of mathematical models should be used, in terms of constitutive law of concrete, crack model and bond slip between concrete and reinforcement. The best combination of analytical conditions, at this moment, was proved to be as below, through the comparative study of analytical and experimental results.1. Use discontinuously rotating crack model where the limiting angle for rotation is the function of crack width.2. For concrete under both compression and tension, use softening curves determined based on the fracture energy. As the equivalent length of the element, use length of intersection line.3. Consider reduction of concrete compressive strength due to the tensile strain in the perpendicular direction.Consider bond slip between concrete and reinforcement.