Micromechanical Polycrystalline Damage-Plasticity Modeling for Metal Forming Processes

International audienceThis chapter deals with the presentation of micromechanical modeling of the elastoplastic material behavior exhibiting ductile damage together with microstructural evolution in terms of grain rotation and phase transformation, under large inelastic strains. A description of the main experimental methods is proposed and multiscale measurements are discussed. For the mesoscopic scale, diffraction techniques are presented as well as microscopy’s results for a specific material. For the macroscopic scale, techniques of tensile test coupled with digital image correlation are described. This allows the damage measurement at different scales. Micromechanical modeling aspects based on the thermodynamics of irreversible processes with state variables defined at different scales are discussed. A non-exhaustive review of several possible models is given. These models depend on the hypothesis for the energy or strain equivalence and on the smallest scale considered. Two particular models are then detailed with their associated constitutive equations and the corresponding numerical aspects. Application is made to two different materials to test the ability of the model to be used for metal forming simulations