The experimental characterization of ductile fracture in Advanced High Strength Steels (AHSS) is influenced by the choice of specimen geometry used to represent specific stress states. In this work, a comparative experimental assessment of different specimen geometries designed to represent uniaxial tension and shear-dominated stress states in DP1000 is presented. A Smiley shear specimen and two mini-shear specimens with 0 mm (‘MiniShear0’) and −1 mm (‘MiniShear-1’) offsets were used to represent shear loading conditions. For uniaxial tension, conventional Dogbone specimens and Central Hole specimens manufactured through laser cutting and electro-discharge machining were tested. Digital Image Correlation (DIC) was employed to analyze strain-field evolution, strain-path stability, and deformation proportionality throughout loading up to the assumed fracture initiation point. The results highlight significant differences between specimen geometries in terms of stress-state stability. Among the uniaxial tension stress state, the Dogbone specimen exhibited the most stable and proportional strain-path evolution, closely approaching ideal uniaxial tension conditions. For shear-dominated loading, while all shear specimens converged toward low stress triaxiality, the mini-shear geometries showed the most homogeneous strain-field behavior.
Pereira et al. (Wed,) studied this question.