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.