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Analyse des instabilités plastiques dans les matériaux ductiles endommageables : application à la prédiction de la striction et de la formabilité des tôles métalliques

Abstract : The phenomenon of necking is generally precursor to ductile fracture, andrepresents one of the main causes leading to defective parts in sheet metal forming. Theimplementation of theoretical and numerical tools capable of predicting this type of defects isthus made necessary for economic and environmental reasons. These tools require in part theuse of an adequate behavior model in order to reproduce the underlying key physicalphenomena. Such a constitutive model is then coupled with a plastic instability indicatorallowing us to reliably predict diffuse and localized necking. In the present work, we haveconsidered some micromechanics damage models based on Gurson’s approach, which werecoupled with different plastic instability criteria based on Bifurcation Analysis. The numericalimplementation of these models was achieved in the implicit finite element codeAbaqus/Standard. With regard to damage models, several time integration schemes weretested to analyze their performance and robustness when the material behavior exhibitspronounced softening effects. The approach combining the constitutive model coupled withdamage and the necking criteria has been then applied to the prediction of formability limits,both at diffuse and localized necking, of several metallic materials. The obtained results allowedus to establish a theoretical and numerical classification of the plastic instability criteria used.
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Submitted on : Monday, January 4, 2021 - 4:06:08 PM
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  • HAL Id : tel-01312915, version 1

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Lotfi Zoher Mansouri. Analyse des instabilités plastiques dans les matériaux ductiles endommageables : application à la prédiction de la striction et de la formabilité des tôles métalliques. Mécanique des matériaux [physics.class-ph]. Ecole nationale supérieure d'arts et métiers - ENSAM, 2014. Français. ⟨NNT : 2014ENAM0059⟩. ⟨tel-01312915⟩

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