Abstract Digital image correlation is utilized to detect automatically crack density in glass/epoxy laminates with different lay-ups under quasi-static and fatigue loading conditions. The DIC setups used in the present work are 2D-DIC and 3D-DIC which are considered to be at meso-scale and macro-scale, respectively. The main objective of this work is to study whether the DIC technique is reliable in automatic crack detection and functional in calculation of crack density. Therefore, an optimization analysis is implemented to evaluate the resolution and the standard uncertainty in strain and displacement measurements. An optimized compromise is attained between the resolution and the uncertainty of both measurements to decide about the final configuration of the DIC setup. The setup is executed by acquiring in-situ images under quasi-static and fatigue experiments so that the images are synchronized with the data acquired from the testing machine. The crack detection analysis is attained by DIC analysis using strain and displacement fields in order to obtain optimum results. Then a semi-automatic program is created to evaluate the crack density and weighted crack density from the edge and top of the specimen, respectively. Moreover, a comparison is established between both strain and displacement fields in crack characterization. Consequently, the displacement field has proved to deliver better and more accurate results than strain fields in crack density calculation and individual crack characterization. Accordingly, the results obtained from DIC analysis are compared and validated by microscopic images which are acquired after performing each test.

中文翻译：

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使用多尺度数字图像相关性在准静态和疲劳载荷下自动检测玻璃纤维复合层压板中的层裂纹边缘

摘要 利用数字图像相关技术，在准静态和疲劳载荷条件下，自动检测不同铺层的玻璃/环氧树脂层压板的裂纹密度。目前工作中使用的 DIC 设置是 2D-DIC 和 3D-DIC，它们分别被认为是在中尺度和宏观尺度上。这项工作的主要目的是研究 DIC 技术在自动裂纹检测和裂纹密度计算中是否可靠。因此，实施优化分析以评估应变和位移测量中的分辨率和标准不确定度。在两种测量的分辨率和不确定性之间获得优化的折衷，以决定 DIC 设置的最终配置。通过在准静态和疲劳实验下获取原位图像来执行设置，以便图像与从试验机获取的数据同步。裂纹检测分析是通过使用应变和位移场的 DIC 分析来实现的，以获得最佳结果。然后创建一个半自动程序来分别评估试样边缘和顶部的裂纹密度和加权裂纹密度。此外，在裂纹表征中的应变和位移场之间建立了比较。因此，在裂纹密度计算和单个裂纹表征中，位移场已被证明比应变场提供更好和更准确的结果。因此，