Strain localization analysis using large deformation anisotropic elastoplastic model coupled with damage

Abstract

This work aims to study the strain localization during the plastic deformation of sheets metals. This phenomenon is precursor for the fracture of drawing parts, so its prediction using advanced behavior models is an active research field. Most often, an accurate prediction of localization requires damage to be considered in the simulation. For this purpose, an advanced, anisotropic elastoplastic model has been coupled with a classical, isotropic damage model. The coupling with the damage model is carried out in the frame of continuum damage mechanics. In order to detect the localization during sheet forming, Rice’s localization criterion is introduced. The coupled elastoplastic damage model is implemented in the Abaqus/Implicit software, via the user routine UMAT, while Rice’s criterion is incorporated in the same code, via the user routine UVARM. Simulations of typical rheological tests are performed in the numerical investigation. The predicted forming limits are very consistent with literature results. The fully 3D formulation adopted in our development allowed for some new results – like the out-ofplane orientation of the normal to the localization band.