混凝土受压性能的均质细观数值模拟

将混凝土看作由骨料、砂浆及它们之间的界面组成的三相复合材料，在细观层次上建立了均质混凝土棱柱体试件的随机骨料模型，分别赋予细观单元弹脆性和弹塑性本构关系，研究了采用不同本构关系的混凝土棱柱体试件在单轴压缩荷载作用下的细观损伤演化过程，分析了宏观应力应变曲线的差异，并将计算结果与试验结果做了比较。结果表明：混凝土试件的破坏是由于细观损伤的积累导致的；界面相是混凝土材料内部最薄弱的地方；砂浆单元采用弹塑性本构关系时所得混凝土棱柱体受压的宏观应力－应变全曲线与试验结果吻合较好。

MESOSCOPIC NUMERICAL SIMULATION ON COMPRESSIVE BEHAVIOUR OF HOMOGENEOUS CONCRETE

In order to study the compressive behavior of concrete under uniaxial compressive load on mesoscopic level, considering the concrete as a three-phase composite material of aggregate, mortar and the interface between them, a random aggregate model at mesoscopic level using monte carlo method was developed. Mesoscopic numerical models for homogeneous concrete were established, in which elastic brittle constitutive relationship for aggregate and the interface elements, and elasto-plastic constitutive relationship for motar elements were adopted,respectively. The results show that the failure of concrete is mostly due to the accumulation of damage at mesoscopic level, and the predicted macro-stress strain relationships of concrete under uniaxial compression agree better with test results when using elasto-plastic relationship for motar element.