Direct Experimental Calibration of Hosford–Coulomb and Modified Mohr–Coulomb Damage Criteria in AHSS Using Digital Image Correlation

This study presents a Digital Image Correlation (DIC)-based experimental framework for the calibration of the Hosford-Coulomb (HC) and Modified-Mohr Coulomb (MMC) damage initiation criteria in an Advanced High Strength Steel (AHSS) DP1000. Three characteristic loading conditions in sheet metal forming—pure shear, uniaxial tension, and plane strain tension—were reproduced using flat specimens in a universal tensile testing machine, thus eliminating the need for costly and time-consuming tooling systems. An additional notch tension specimen was employed to validate the stress-state sensitivity of the proposed calibration approach. By integrating full-field strain data from DIC with tensile test results, stress–strain relationships were directly obtained without finite element modeling. The results confirm the effectiveness of dogbone, mini shear, and plane strain tension specimens in achieving proportional loading path histories up to fracture initiation, with constant stress state evolution during deformation. Comparison of the HC and MMC damage criteria reveals similar fracture loci, with the HC model exhibiting slightly higher resistance between shear and uniaxial tension conditions. This study discusses the suitability of a fully experimental DIC-based methodology for the calibration of stress-state-dependent damage initiation criteria. The results highlight the ability of the proposed methodology as a simplified and lower time-consuming alternative to traditional numerical assisted frameworks.