混凝土四相复合模型的三维细观破坏模拟

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发布时间：2022-03-03

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：考虑到混凝土内部细微裂隙的存在对混凝土强度和变形的重要影响，提出将混凝土视为砂
浆、骨料、界面和随机缺陷组成的四相复合材料模型。混凝土细观单元服从应变空间内增量形式的
弹塑性损伤本构，采用破坏单元网格消去法模拟混凝土裂纹扩展，数值模拟了三维混凝土单轴压缩
和不同均质度试样的单轴拉伸弹塑性损伤破坏过程。结果表明：文中建立的混凝土四相复合材料
模型中增加随机缺陷的模拟，一定程度上符合混凝土成形实际情况；随机缺陷的体积百分比是决定
弱化混凝土宏观强度程度的主要因素；均质度低的单轴拉伸试样裂纹咬合明显，均质度高的试样断
裂更清晰，数值模拟结果与试验结果较吻合。
关键词：混凝土；四相复合材料；弹塑性损伤；随机缺陷；破坏单元网格消去法
中图分类号：TU317．1 文献标志码：A 文章编号：1674—4764(2009)04—0037—07
3D M eso-scale Failure Simulation of Four-phase Composite Concrete
zHA0 Ji-kun
(College of Engineering，Nanjing Agricultural University，Nanjing 210031，P．R ．China)
Abstract：Taking into account the influence of the internal micro cracks on the strength and deformation of
concrete，a four—phase composite material model was proposed， in which it included mortar，aggregate，
interface and random defects． Meso—scale unit in concrete was subjected to elastic—plastic damage
constitutive of increments form in strain space． W ith the sim ulation of mesh concrete crack growth by
damage elimination，the damage processes of concrete under 3-D uniaxial compression and the elasto—plastic
damage process of concrete under uniaxial tension with heterogeneous specimen were obtained． It was
show n that the proposed four—phase model added the simulation of random defects，with which it was more
appropriate to the actual situation in concrete form ing．The percentage of random defects in volum e was the
key to determine the weakening degree of m acro—strength of concrete．The cracks occlusion was obvious for
the lower homogeneous uniaxial tension specimen and the fracture was clearer for higher homogeneous
specimen．The simulation results was in good agreem ent with test results．
Key words：concrete；four—phase com posite m aterials；elasto—plastic damage；random defects；mesh damage
elimjnatjon
在细观层次上，混凝土是由粗、细骨料、水泥水
化产物、未水化水泥颗粒、孔隙、裂缝等所组成的连
续不匀质的多相复合材料。因此，研究人员提出了
一些研究混凝土细观问题的数值模型。杜修力教
授利用蒙特卡罗方法生成混凝土随机骨料模型，
将混凝土视为由骨料、水泥砂浆及二者间的粘结带
所构成的三相复合材料，其他学者同样将混凝土
模拟为三相复合材料，主要在骨料形状和投放方法