混凝土单轴压缩CT观测及三维变形场计算分析

发布时间：2018-02-08 21:51

本文关键词： 岩土工程混凝土单轴压缩 CT扫描三维变形场数字体散斑法　出处：《工程力学》2017年05期 　论文类型：期刊论文

【摘要】：利用微焦点工业CT对混凝土试件单轴压缩过程分阶段进行原位扫描,获得相应的系列CT图像。由数字体散斑法(Digital Volumetric Speckle Photography,DVSP)获得了试件内部三维位移场与应变场。混凝土内部非均匀细观结构可以作为散斑结构成为变形信息的载体用于试件内部变形的测量;通过位移场和应变场的分析,揭示了试件内部变形局部化区域的演化及破坏过程,局部化区域与试件最终破坏面位置相一致。根据试件的体积应变随轴向应力的变化曲线分别定义了小于CT尺度微裂隙和CT尺度裂隙的发育点,分别为峰值应力的54.7%和82.0%,这两点同时对应着试件扩容的起始点及塑性变形的起始点。结果表明,DVSP与CT技术相结合能够直观地揭示混凝土试件内部变形局部化产生及发展过程,为三维变形的精细测量及可视化提供了方法。
[Abstract]:In situ scanning of concrete specimens during uniaxial compression was carried out by microfocal industrial CT. The 3D displacement field and strain field of the specimen were obtained by digital Volumetric Speckle photography with digital volume speckle method. The non-uniform mesoscopic structure of concrete can be used as the carrier of deformation information for speckle structure. The measurement of the internal deformation of the specimen; Through the analysis of displacement field and strain field, the evolution and failure process of the localized deformation region in the specimen are revealed. The localization region is consistent with the location of the ultimate failure surface of the specimen. According to the curves of the volume strain and axial stress of the specimen, the development points smaller than the CT size microfracture and the CT scale fracture are defined, respectively. The results show that the combination of DVSP and CT technology can directly reveal the process of the localization of deformation in concrete specimens, which corresponds to the initial point of expansion and the starting point of plastic deformation, respectively, which are 54.7% and 82.0 of the peak stress, respectively, and the results show that the combination of DVSP and CT technology can directly reveal the process of the localization of deformation in concrete specimens. It provides a method for fine measurement and visualization of three dimensional deformation.
【作者单位】：中国矿业大学(北京)力学与建筑工程学院;北京城市学院城建学部;中国矿业大学煤炭资源与安全开采国家重点实验室;
【基金】：国家自然科学基金项目(51374211,51274209,41472259) 国家重大科学仪器设备开发专项项目(2013YQ240803) 中央高校基本科研业务费专项资金项目(2009QM02)
【分类号】：TU528

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