Measuring true stress–strain curves of cylindrical bar samples with mirror-assisted multi-view digital image correlation

This paper proposes to measure true stress–strain curves at the necking region of cylindrical bar samples by using an advanced mirror-assisted multi-view digital image correlation (MV–DIC) technique. The mirror-assisted MV–DIC can measure the panoramic shape and deformation fields of a cylindrical bar sample with only a single two-camera stereo-DIC system and two planar mirrors. The measured panoramic shape enables accurate determination of the cross-section area and radius of curvature at the necking region by using cylindrical or torus fitting. The retrieved cross-section area and radius of curvature at the necking region further enable the measurement of the true stress–strain curves and even the Bridgman's correction of the true stress.