黏聚单元嵌入技术及其在混凝土细观分析模型中的应用

采用针对随机颗粒的渐变网格剖分和黏聚单元嵌入的方案,建立骨料-砂浆-界面的三维高效细观有限元模型,并在单机上实现了混凝土标准试样的单轴拉伸和单轴压缩数值试验。结果表明:该嵌入方案能够捕捉到骨料-砂浆界面由弱连接到脱开的全过程,再现混凝土试样的破坏形态;通过对细观模拟结果获得的应力-应变关系曲线的对比分析,一定程度上揭示了混凝土宏观力学特性的内在机理,为探究混凝土类复合材料宏观力学特性的内在机制提供了技术保障。

Embedding technique of cohesive element and its application in concrete mirco-level analysis model

By adopting gradually tetrahedral meshing technique for random distributed aggregates and embedding scheme of cohesive element, a high efficiency 3D aggregate-mortar-interface meso finite element model is established, in which the uniaxial tension and uniaxial compression experiments of concrete cube samples are carried out in single computer. The numerical result shows that the whole process from weak connection to separation between aggregates and mortar is readily captured, which reproduces the failure mode of concrete specimens. The inner mechanism of the macro-mechanical properties of concrete is thus revealed by comparing the computed stress-strain curves from uniaxial tension and compression experiments, which is supposed to provide a technical support to explore the inner mechanism of concrete like composite materials.