混凝土破裂过程三维数值模拟及CT验证

将混凝土简化成由骨料、水泥砂浆及其二者之间的界面层所组成的三相复合材料，建立了混凝土骨料随机分布三维模型，用界面单元多次细分技术进行有限元网格划分，基于弹性损伤本构关系采用双折线损伤演化模型描述混凝土细观各相弹性损伤退化，用弹性模量的折减程度来反映混凝土试件在加载过程中的损伤程度。对混凝土圆柱体试件进行了数值模拟计算，并从混凝土破坏过程图和荷载-位移曲线图两方面比较了数值模拟的破坏过程与CT试验结果，发现试件破坏时裂纹的萌生、扩展过程与CT观测到的过程具有相似性，说明用本文建立的三维数值模型模拟混凝土材料的损伤破坏过程是基本可行的。

3-D numerical simulation of concrete failure process and CT verification

The concrete is conceptually simplified as a three-phase composite material consisting of aggregates, mortar and bonding material, and a model for describing the 3-D random distribution of aggregate is established. The boundary element method and multi-subdivision technology is applied to carry out the meshing. Based on the constitutive relationship of elastic damage the broken-line damage evolution model is adopted to describe the meso-mechanics deterioration of elastic damage of concrete and the damage of concrete in the process of loading is reflected by the decrease of elastic modulus. The failure of a cylindrical concrete specimen is numerical simulated by the proposed method. The failure process graph and load-displacement relationship are verified by experiment using CT technology. It is found that the calculated initiation and development of cracking during failure are in good agreement with the experimental data. It shows that the proposed 3-D numerical model is feasible in simulating the damage and failure of concrete material.