Abstract
Three different tools for Digital Image Correlation (DIC) were used for evaluation of dynamic experiments performed using custom Open Hopkinson Pressure Bar (OHPB) apparatus. High strain-rate measurements were performed on specimens of advanced cellular materials with predefined structure and negative Poisson’s ratio. Low impedance polymethyl methacrylate (PMMA) bars instrumented with foil strain-gauges were used for dynamic loading of the specimens. Experiments were observed using a pair of high-speed cameras for imaging of loading process in sufficient quality. Custom developed evaluation DIC tool implemented in Matlab, open-source Matlab tool (NCorr) and commercial DIC software (ISTRA 4D) were all used for evaluation of image sequences recorded by high-speed cameras. Comparison of results obtained using all three different DIC tools and results of complementary strain-gauge measurement are shown in this paper. Verification of reliability of custom made DIC software tool is presented.
Highlights
Digital Image Correlation (DIC) is a well established method used for contactless assessment of full-field maps of displacement and strain on the surface of the deformed specimen
Custom developed evaluation DIC tool implemented in Matlab, open-source Matlab tool (NCorr) and commercial DIC software (ISTRA 4D) were all used for evaluation of image sequences recorded by high-speed cameras
Three different DIC software tools were used for evaluation of direct impact Open Hopkinson Presure Bar (OHPB) experiments performed on specimens of advanced materials with predefined structure and negative Poisson’s ratio
Summary
Digital Image Correlation (DIC) is a well established method used for contactless assessment of full-field maps of displacement and strain on the surface of the deformed specimen. It shows a great promise for evaluation of high strain-rate experiments performed using Hopkinson Bar experimental device with specimens of geometrically complex structures [1]. Three different DIC software tools were used for evaluation of direct impact Open Hopkinson Presure Bar (OHPB) experiments performed on specimens of advanced materials with predefined structure and negative Poisson’s ratio (so called auxetic structures). Obtained results were compared visually and quantitatively. Results were compared with complementary strain-gauge measurement. Correlation of single nodal point of the specimen structure was performed and influence of correlation coefficient was discussed
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