Skip to Main content Skip to Navigation
Theses

Contribution à la modélisation de la mise en forme des tôles métalliques : application au retour élastique et à la localisation

Abstract : The aim of this work, part of a larger European project, was the study of the sheet metals behaviour during forming operations. The applications in mind concern the prediction, through the forming process numerical simulation, of major defects like springback and strain localization. In this context, a phenomenological material modelling has been considered. An elastic-plastic behaviour model has been adopted, in which two hardening models have been introduced to reproduce induced anisotropy during complex loading. The microstructural work-hardening model of Teodosiu-Hu, based on the evolution of dislocation structures, has been considered to take into account transient work-hardening due to the strain-path changes. This model has been improved, by coupling with the Lemaitre-Chaboche damage model, in order to reproduce the softening that appears prior to failure. In addition, in order to represent the ductility limit of the sheet metals, Rice's localisation criterion by shear bands has been introduced and written in the large strain framework. The developed modelling takes into account the initial plastic anisotropy, the work-hardening-induced anisotropy, the damage and finally strain localisation. A robust and efficient computer implementation has been performed in a finite element code, in order to apply the developed models to forming process simulation. Different time integration algorithms have been tested and compared in order to obtain the best compromise between accuracy and computing time. Direct and sequential rheological tests have been simulated in order to validate the computer implementation, with very good results. The application of the elastic-plastic model to a springback analysis has highlighted the effect of various parameters (rheological, numerical, process-related). Especially, the impact of advanced hardening models, like the microstructural one, proved to be important for some specific applications. Eventually, a strain localisation analysis has been performed using Rice's criterion and the elastic-plastic model coupled to damage. This study showed the capability of this approach to predict the forming limit diagrams as well as the orientation of the shear bands, during direct and two-step loading paths.
Document type :
Theses
Complete list of metadatas

Cited literature [176 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00002780
Contributor : Ecole Arts Et Métiers Paristech <>
Submitted on : Thursday, July 19, 2007 - 8:00:00 AM
Last modification on : Monday, April 16, 2018 - 10:42:04 AM
Long-term archiving on: : Wednesday, September 8, 2010 - 5:39:07 PM

Identifiers

  • HAL Id : pastel-00002780, version 1

Citation

Badis Haddag. Contribution à la modélisation de la mise en forme des tôles métalliques : application au retour élastique et à la localisation. Sciences de l'ingénieur [physics]. Arts et Métiers ParisTech, 2007. Français. ⟨NNT : 2007ENAM0002⟩. ⟨pastel-00002780⟩

Share

Metrics

Record views

731

Files downloads

2978