基于CT图像的混凝土细观力学层次模型重建

基于已研究的混凝土随机模型和CT重建模型,本文从混凝土CT扫描切片入手,结合已有模型的特点,根据CT数的物理含义,依据自行编制的程序,重建了混凝土模型。模型以CT图片为基础,考虑了CT图像中的所有信息,包括骨料的形状、级配、孔洞等。对骨料和砂浆结合部位进行了考虑,摒弃以前加接触单元的方法,在骨料和砂浆之间加了一层界面单元,并对模型进行了动压、动拉荷载作用下的力学分析,与CT物理试验结果进行对比验证。结果表明:该模型可以很好的进行混凝土数值试验。

Reconstruction of micromechanics hierarchical models of concrete based on CT images

This paper presents a random model for concrete materials from CT scanning of concrete sections and a reconstruction model using the information abstracted from CT images. According to the physical meaning of CT number, we have developed a computer code for the reconstruction by integrating the characteristics of existing models. This reconstruction model considers various types of information abstracted from the CT images, including the shapes and gradation of aggregates and the features of pores. Adhesion of mortar to aggregates is modeled using a new method of adding one layer of interface elements between aggregates and mortar, in replacement of the traditional method of adding contact elements. We conducted a detailed analysis on the mechanical behaviors of concrete under dynamic loads, compressive or tensile, and made a comparison with the CT test results. The analysis shows that the reconstruction model has good performances in numerical tests of concrete.