于庆磊, 杨天鸿, 唐世斌, 刘洪磊, 梁正召, 郑喜, 贾蓬. 基于CT的准脆性材料三维结构重建及应用研究[J]. 工程力学, 2015, 32(11): 51-62. DOI: 10.6052/j.issn.1000-4750.2014.06.0474
引用本文: 于庆磊, 杨天鸿, 唐世斌, 刘洪磊, 梁正召, 郑喜, 贾蓬. 基于CT的准脆性材料三维结构重建及应用研究[J]. 工程力学, 2015, 32(11): 51-62. DOI: 10.6052/j.issn.1000-4750.2014.06.0474
YU Qing-lei, YANG Tian-hong, TANG Shi-bin, LIU Hong-lei, LIANG Zheng-zhao, ZHENG Xi, JIA Peng. THE 3D RECONSTRUCTION METHOD FOR QUASI-BRITTLE MATERIAL STRUCTURE AND APPLICATION[J]. Engineering Mechanics, 2015, 32(11): 51-62. DOI: 10.6052/j.issn.1000-4750.2014.06.0474
Citation: YU Qing-lei, YANG Tian-hong, TANG Shi-bin, LIU Hong-lei, LIANG Zheng-zhao, ZHENG Xi, JIA Peng. THE 3D RECONSTRUCTION METHOD FOR QUASI-BRITTLE MATERIAL STRUCTURE AND APPLICATION[J]. Engineering Mechanics, 2015, 32(11): 51-62. DOI: 10.6052/j.issn.1000-4750.2014.06.0474

基于CT的准脆性材料三维结构重建及应用研究

THE 3D RECONSTRUCTION METHOD FOR QUASI-BRITTLE MATERIAL STRUCTURE AND APPLICATION

  • 摘要: 准脆性材料的结构及其细观组分的力学性质决定了材料的力学性质及破裂机制,在数值模型中尽可能准确的考虑材料的真实结构已成为了数值计算与数值模拟发展的一种趋势。该文以混凝土为研究对象,借助于先进的CT技术获取混凝土内部结构切片图像,利用数字图像处理技术实现了基于CT图像的混凝土材料结构的识别和表征,并针对CT图像具有颜色亮度不均并呈环状分布的特点,提出了环状分区与分割阈值自动识别相结合的CT图像分割算法;在此基础上,建立了基于位图矢量化理论的三维实体材料结构模型的重建方法和三维网格化材料结构模型重建方法,并将三维网格化方法建立的材料结构模型与三维岩石破裂过程分析系统RFPA3D结合进行了初步应用,对混凝土单轴压缩破裂过程进行了数值模拟。通过数值试验与物理实验结果对比发现,考虑混凝土骨料真实分布的数值实验结果与物理实验具有一定可比性,数值试验结果从得到的力学参数和破裂模式方面比较接近于物理实验结果,为深入研究混凝土、岩石、复合材料等力学特征提供了一种可行的研究思路。

     

    Abstract: Physical and mechanical properties of quasi-brittle mater as well as its failure mechanism are determined by the material structure and the properties of each constituent. Therefore, it has become a developing trend to consider the actual structure of material as accurate as possible in numerical methods. In this paper, computerized tomography (CT) technology is employed to capture a serial of section images of the concrete material structure. Because the color density of CT image is uneven and annular distribution, a segment method based on annular zonal method and automatically identifying threshold is proposed to identify and characterize the concrete material structures from CT images. After that, the reconstruction methods for the 3D digitized solid model of material structure based on the vectorization of the BMP image and for the 3D grid model of material structure have been developed. Finally, the 3D grid model of the concrete material structure is transferred into the 3D Rock Failure Process Analysis (RFPA3D) to build a numerical concrete specimen which can reflect the actual distribution of coarse aggregates, and the uniaxial compressive test of concrete is simulated. It is found that the results of the numerical test in which the actual distribution and geometry of coarse aggregates are taken into account are of comparability with the experimental results. The mechanical parameters and final failure patterns of the specimen from the numerical test are similar to those from the experimental test, which provides a new method for studying the mechanical behaviors of quasi-brittle materials such as concrete, rock and composite materials.

     

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