混凝土细观随机骨料结构与有限元网格剖分

Random aggregate structure of mesoscopic concrete and finite element mesh

在细观层次上,混凝土被认为是一种由粗骨料、水泥砂浆及二者间的粘结带所组成三相非均质复合材料。本文首先基于蒙特卡罗随机抽样原理,用“取和放”方法在计算机上产生形状、尺寸和骨料颗粒分布与真实混凝土相似的随机骨料结构,再使用有限元分析软件AN SY S对骨料区域及砂浆区域分别划分网格,并编程在骨料和砂浆之间生成三角形三结点可控制厚度粘结单元,从而使三相网格缝合为一个整体,为混凝土非线性有限元分析提供可靠的细观计算模型。最后利用建立的模型进行混凝土轴心受拉和轴心受压的仿真模拟,在细观层次研究的基础上揭示出混凝土的宏观力学性能。

Concrete is a composite material with a three-phase of heterogeneity in mesoscopic level. In this paper, a procedure that adopts the take-and-place method to generate random aggregate structures based on the Monte Carlo random sampling principle. The random aggregate structure in which the shape, size and distribution of the aggregate particles resemble real concrete. Then meshing the aggregate domain and the mortar matrix domain separately using finite element analysis software： ANSYS and generating triangle and three-node element with controllable thickness in the interface domain by procedure. So the three-phase mesh can set up. The mesh is a mesoscopic calculation model of nonIinear finite element analysis of concrete. Finally the model is applied to simulate the process of concrete trial under axial tension and axial compression. Some macro-properties of concrete are obtained on the base of mesolevel research and reveal the mechanism of mesolevel failure of concrete.