Evaluation of anisotropic fracture in AA1050-O sheet using uncoupled ductile fracture models with Hill48 plasticity

Abstract

Uncoupled ductile fracture models have gained popularity for accurate prediction of fracture in ductile metallic sheets due to their ease of implementation. Accurate description of anisotropic fracture behavior is an active research field for sheet metal forming. In the present study, two isotropic ductile fracture models, i.e., modified Mohr-Coulomb and Hosford-Coulomb are evaluated for an O-tempered aluminum alloy (AA1050-O) sheet. The plastic anisotropy is modeled with a non-associated Hill48 plasticity model. In order to verify the models, experiments are conducted for a 1.2 mm thick AA1050-O sheet under various loading conditions, such as uniaxial tension, in-plane shear, and plane strain tension at room temperature. For evaluating the anisotropic ductile fracture, tensile tests are carried out in 15° intervals to the rolling direction using digital image correlation technique. The predicted fracture limit strains by the two uncoupled fracture models are compared with experimental results to evaluate the accuracy of these models.