This paper aims to explore the DIC technique for use in wide width tensile testing of geogrids, from specimen preparation to selection of DIC parameters required for analysis to provide a guide for a proper use. A series of monotonically loaded wide width tensile tests were conducted on a PET geogrid to investigate the effects of specimen surface preparation methods and the user-defined DIC parameters. An additional set of tests under cyclic loading was conducted to investigate the effect of the image sampling rate. The results indicate that the speckle pattern (image texture) has a significant effect on the DIC results such that the larger is the speckle size, the greater is the uncertainty level, eventually leading to increased nonuniformity in the calculated strains. Also, it was revealed that a subset size smaller than optimal, typically 20–30 pixels, results in highly localized strain distribution. A similar trend was observed in step size. In addition, the image sampling rate was found to have a significant effect on the DIC-calculated cyclic strains, such that the lower is the image sampling rate, the lower is the calculated cyclic strain.

中文翻译：

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数字图像相关技术在土工格栅宽幅拉伸试验中的应用


本文旨在探索 DIC 技术在土工格栅宽幅拉伸试验中的应用，从试样制备到分析所需 DIC 参数的选择，为正确使用提供指导。在 PET 土工格栅上进行了一系列单调加载的宽幅拉伸试验，以研究样本表面处理方法和用户定义的 DIC 参数的影响。在循环加载下进行了一组额外的测试，以研究图像采样率的影响。结果表明，散斑图案（图像纹理）对 DIC 结果具有显着影响，散斑尺寸越大，不确定性水平越大，最终导致计算应变的不均匀性增加。此外，研究还发现，小于最佳大小（通常为 20-30 像素）的子集大小会导致高度局部化的应变分布。在步长方面也观察到类似的趋势。此外，还发现图像采样率对DIC计算的循环应变有显着影响，图像采样率越低，计算出的循环应变越低。