Material parameter identification within an integrated methodology considering anisotropy, hardening and rupture

• Mechanical behavior of mild steel considering anisotropy, hardening and rupture.
• Inverse identification of numerous material parameters from homogeneous tests.
• Macroscopic rupture criterion identified from tensile test up to rupture.
• Validation on a cup drawing experiment with either full drawing or premature rupture.

The main focus of the present work is the development of a global procedure for a complete characterization of sheet metal behavior, including anisotropy, evolution of hardening and rupture. This efficient procedure involves the mechanical characterization, at room temperature and in quasi-static conditions, of the material up to large strains by evaluating the local strain field. The initial anisotropy, hardening and rupture of DC04 mild steel are characterized using a complex phenomenological model composed by the non-quadratic Yld2004-18p yield criterion combined with a mixed isotropic-kinematic hardening law and a macroscopic rupture criterion. For this purpose, an inverse methodology for material parameter identification is implemented based on several experimental tests considered as homogeneous and also, a mixed experimental-numerical approach to calibrate the rupture criterion is performed. In order to validate the obtained results, a deep drawing test, leading either to full drawing or rupture of the blank, is carried out. Digital image correlation is used to acquire additional data information in the deep drawing test. Strain fields at several stages of the deep drawing experiment are evaluated leading to a better comparison between the experimental observations and the results of the numerical simulation.