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| 基于可靠子区DIC方法的裂纹位移场测量 |
| Crack displacement field measurement based on the Reliable Subset Digital Image Correlation Method |
| 投稿时间：2023-08-22 修订日期：2023-10-22 |
| DOI： |
| 中文关键词: 数字图像相关方法 裂纹 位移场测量 可靠子区 数据分类 |
| 英文关键词:digital image correlation method crack displacement field measurement reliable subset data classification |
| 基金项目:国家自然科学基金(52074142)、山西省基础研究计划青年科学研究项目（2022032122325）、山西工程技术学院引进人才科研启动经费（2022QD-09） |
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| 中文摘要: |
| 裂纹位移场测量是数字图像相关(DIC)方法应用面临的难题之一。可靠子区DIC方法充分结合了SIFT特征匹配和DIC方法的优势，通过SIFT特征匹配选择DIC方法中的子区（可靠子区），这种子区的相关运算不易受到裂纹的影响。在该方法中，测点的变形参数是通过其周围多个可靠子区中心点位移拟合得到。裂纹附近位移场具有非连续性，而在拟合时采用连续型拟合函数，这会使得裂纹附近测点的位移测量存在较大的误差。针对这种情况，采用了对拟合区域内的可靠子区中心点进行分类的方法降低误差。在分类时，首先，通过位移变异系数判断拟合区域内是否包含裂纹。然后，通过位移极值比较方法对包含裂纹的拟合区域内的可靠子区中心点进行分类。最后，选择合适的一类数据点进行拟合获取测点变形参数。采用I型裂纹模拟散斑图实验和相似材料单轴压缩实验验证了可靠子区DIC方法的有效性。结果表明，对于裂纹位移场测量，可靠子区DIC方法具有较高的精度和可靠性。 |
| 英文摘要: |
| Crack displacement field measurement is one of the challenges faced in the application of digital image correlation (DIC) methods. The reliable subset DIC method can fully combines the advantages of SIFT feature matching and DIC method, and subsets (reliable subsets) in the DIC method are selected by SIFT feature matching. Correlation operations of these subsets are not easily affected by cracks. In this method, the deformation parameters of points of interest (POIs) are obtained by fitting displacements of the center points of reliable subsets around them. The displacement field near the crack has discontinuity, which can lead to significant errors in displacement measurements of POIs near the crack by use of a continuous fitting function. A method of classifying reliable subset center points within fitting regions is used to reduce the errors. First, displacement variation coefficients are used to determine whether there are cracks in fitting regions before classifying. Then, reliable subset center points in fitting regions with cracks are classified by the displacement extremum comparison method. Finally, deformation parameters of POIs are obtained by fitting a suitable type of data points. The effectiveness of the RS-DIC method was verified by a simulation speckle pattern experiments of mode I crack and a uniaxial compression experiment of similar material. The results indicate that the RS-DIC method has high accuracy and reliability for crack displacement field measurement. |
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