基于渐变网格剖分方法的再生混凝土细观数值试验

Meso-numerical Experiment of Recycle Concrete Based on Gradually Mesh Division Scheme

细观上,把混凝土看成是由骨料、砂浆以及它们之间的界面等组成的多相复合材料,对于光滑的球形骨料,预先进行镶边处理,并在此基础上首先对封闭域形成表面单元,然后采用拓扑映射的渐变网格剖分方法往里拓扑成四面体单元网格,按同样方法依次生成界面单元网格和砂浆单元网格,删除表面单元和多余节点后形成混凝土试件的三维细观有限元网格模型。采用该细观有限元模型进行再生混凝土的单轴压缩数值破坏试验,结果表明,该网格模型在单机环境下很快的就能完成数值试验,与以往的自由网格剖分法和映射网格剖分法生成的细观有限元模型相比不仅在计算规模上大大缩小了,而且模拟的破坏形态与实际非常吻合,精度也很高。

Based on the surface trimming technique,a gradually Delaunay tetrahedron division scheme is proposed to mesh the concrete specimen which can be taken as an inhomogeneous multi-phase composite consisting of mortar matrix,aggregates and the bond between them in mesoscopic.By this scheme,the sphere or ellipsoid aggregate can be meshed easily and the amount of elements generated is far less than that by the free mesh division scheme and the map mesh scheme,according to the same precision.By the gradually mesh division scheme,the 3D concrete meso finite element models are established.Finally,with these models,uniaxial compress numerical fracture experiments of recycle concrete specimens have been made,and their failure processes are also simulated.The simulation process and result show that the computation efficiency is much higher when compared with the finite element model established by the map mesh scheme or the free mesh division method on the same precision.What's more,the fracture form by simulation agrees better with experiments.