Extension of the DF2016 isotropic model into an anisotropic ductile fracture criterion

The paper extends the recently proposed ductile fracture criterion of DF2016 (Lou, Chen, Clausmeyer, Tekkaya and Yoon, 2017. Modeling of ductile fracture from shear to balanced biaxial tension for sheet metals. International Journal of Solids and Structures 112, 169-184) to consider the anisotropic ductile fracture behaviour of sheet metals. The DF2016 criterion is coupled with the Hill48 yield function to model the anisotropy in ductile fracture. For the verification purpose, experiments are conducted for AA6082-T6 sheet with a thickness of 1.0 mm in various loading conditions: in-plane shear, uniaxial tension, plane strain tension, and the balanced biaxial tension. Tests are carried out in the rolling direction, diagonal direction and transverse direction. Fracture strains are measured by digital image correlation along different loading directions. The anisotropic fracture of the sheet is modelled by the DF2016 criterion by incorporating an anisotropic yield function. The predicted anisotropic fracture loci are compared with experimental results in shear, uniaxial tension, plane strain tension and balanced biaxial tension. The comparison demonstrates that the anisotropic DF2016 criterion accurately models the anisotropic fracture behaviour of AA6082-T6 sheet in wide loading conditions from shear to balanced biaxial tension.