New Development of Digital Volume Correlation for the Study of Fractured Materials
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This study reports on Digital Volume Correlation and its limitation in the case of fracture mechanics. Due to its sensitivity, detecting the crack opening in sub pixel level is extremely difficult and in-turn it does not provide an accurate estimation of the stress intensity factors. To address these limitations an improved DVC method was proposed to solve the uncertainty problems in the vicinity of cracks. The method (H-DVC) was developed using classical minimization process, including Heaviside functions in the kinematical field representation. Initial simulation has been performed for opening and sliding modes using classical DVC and proposed H-DVC. From these tests, crack detection limit has be evaluated to a jump of 0.1 voxels. A direct comparison of performances of DVC and H-DVC has been carried out on a fractured polymer sample to detect the kinematics discontinuity and to highlight the significant contribution of this novel approach. Furthermore, the local Crack Opening Displacement and local Stress Intensity Factor (KI) are calculated for mode-I loading (opening mode activated) condition. Parallelized computation of the proposed H-DVC method gave an access to high-resolution details, which indeed are not observable using classical DVC method. This allows a better evaluation of the distribution of localization phenomena in volumes under loading.
KeywordsDigital volume correlation Fracture Full field measurement Cracks High resolution
This work was partially funded by the French Government program “Investissements d’Avenir” (EQUIPEX GAP, reference ANR-11-EQX-0018).
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