Theoretical modelling of ductile damage in Duplex stainless steels- Comparison between two micro-mechanical elastoplastic approaches.
Computational Materials Science
Ductile damage is a consequence of large strains more or less localized. Taking into account damage in constitutive behaviour of metallic materials is necessary to model forming processes (stamping, punching, shearing...). It would lead to accurate prediction only taking into account microstructural features of the material [1-2]. In this study, comparisons between several models with or without damage using transitions scales methods are presented. Two main modelling are developed based on different approaches with application to duplex stainless steel. The first approach is a generalized Cailletaud-Pilvin model taking into account damage. The second one is a variant of the Berveiller-Zaoui-Lipinski model taking also account damage. Because of the microstructural complexity of this material, some particular developments of the micromechanics approach are considered. Moreover, use of a continuous damage approach (CDM) is done at grain scale including its effect (or coupling) on plastic or elastoplastic flow with more or less complex isotropic hardening. The modelling is justified on some previous experimental results on damage in metallic materials [3-4]. Models developed allow deducing the macroscopic behaviour with damage effects from the grains local behaviour. Then, experimental loading tests at macroscopic scale enable to identify some parameters with an inverse method approach. Finally, some comparisons with experimental results from neutron diffraction measurements at mesoscale are done.