【摘要】 为了研究混凝土材料的细观结构破坏机理,将其视为由骨料、界面、水泥浆和孔隙组成的复合材料。利用微焦点工业CT对试件进行扫描,获得高精度CT图像。通过图像处理与分割,应用Mimics软件建立三维数值模型,采用有限元软件ANSYS进行数值模拟并与试件单轴压缩CT原位扫描试验进行对比。结果表明:试件内部界面是其薄弱部位,裂纹首先在界面处产生,沿界面扩展到水泥浆,同时裂纹也会穿过部分骨料,最终贯通形成破裂面。通过对比发现数值模拟高应变区的萌生、扩展、联通与试件单轴压缩CT试验的破坏过程以及最终的破裂面形状都具有一致性,表明该建模方法是可行性。该模型能够充分反映试件内部真实结构特征,为数值方法研究混凝土材料细观特性提供了建模手段。更多还原

【Abstract】 In order to study the meso- scale failure mechanism,the concrete is considered as a composite material consisting of aggregate,interface,liquid cement and pore.By using micro focus industrial computer tomography,the specimen was scanned and the CT images in high resolution were obtained.After CT image processing and segment,the three dimensional numerical model for ANSYS was built with the aid of Mimics software.By comparing the results of the numerical simulation with that of uniaxial compression experiment by using CT scan in situ,it is shown that the interface is the weakest part and the cracks are generated from the interface at first.Along the interface,the cracks extend to the liquid cement,meanwhile the cracks pass through some aggregates coalesce,and then form the failure surface.It can be found that the initiation and development of the high strain areas in the sample numerical model are consistent to the destruction of the specimen under uniaxial compression,which indicates that the method proposed to build model is feasible.The real structure characteristics of the sample can be reflected in this model which provides a new model building mean to research meso-scale characteristics of the concrete by using numerical simulation.更多还原