Browsing by Author "Brisley, JE"

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    An open-source digital image correlation software system.
    (Stellenbosch : Stellenbosch University, 2024-02) Brisley, JE; Venter, G; Conradie, PDF; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT:Digital Image Correlation (DIC) is a popular computer vision-based optical measurement technique typically used for material characterisation and load response tests. In this project, an open source software system in Python is developed for full-field DIC measurements. An overview of the numerical implementations underpinning local and global planar-DIC solvers for displacement measurements is provided. It is shown that the planar-DIC implementations accurately recover complex, sub-pixel level displacements, by testing the software on the synthetic image sets made available for the DIC challenge 2.0. The local-DIC implementation achieves metrological performance on par with the benchmark, while the global counterpart achieves metrological performance in the mid-range of the codes participating in the challenge. Strain filters implementing a Gaussian smoothing scheme and linear polynomial fit, respectively, to subsequently filter the displacement data are shown to achieve metrological performance on par with the benchmarks. Stereo-DIC combines the independent planar measurements from two cameras in a triangulation routine to estimate a depth component, and thus 3D fullfield displacement data. The stereo-DIC implementation is validated against displacements as set by a secondary measurement system, namely, high-precision optical translation stages. Additionally, the quantification of measurement uncertainty in stereo-DIC measurements is explored. A tensile test case study is performed to illustrate the influence of different user-defined software settings on the resolution characteristics of the full-field displacement and strain measurements obtained by stereo-DIC.