Anisotropic Elastoplastic Behaviour Fully Coupled with Isotropic Ductile Damage for Sheet Metal Forming

摘要

Sheet metal drawing is an industrial process widely used in automotive production. The present work shows the ability of using the ductile damage concept in order to predict the ductile damage (or fracture) occurrence during the deep drawing of anisotropic thin sheets. For this purpose a constitutive equations accounting for anisotropic elasto-plasticity coupled with the isotropic damage and a combined isotropic and kinematic hardenings are derived from the thermodynamic of irreversible processes. The quadratic Hill's yield criterion is used in order to take into account the initial plastic anisotropy of the sheet metal. The fully coupled model accounting for isotropic and kinematic hardening as well as the isotropic ductile damage is considered. For the local integration, an iterative implicit scheme is used together with a reduction in the number of the integrated constitutive equations and a fully implicit return mapping algorithm. The Dynamic Explicit scheme is also used to solve the equilibrium problem defined by the principle of virtual power thanks to ABAQUS/Explicit software. After the determination of the materials constants using an experimental data base, this numerical procedure has been applied to the numerical prediction of the ductile damage occurrence during various drawing processes. Results concerning the damage occurrence during these drawing processes are analyzed and compared to some available experimental results.