%0 Conference Paper
%F Oral
%T Ductile fracture modelling using local approaches, application to steel welded joints in nuclear components
%+ CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN))
%+ Institut des Sciences de la mécanique et Applications industrielles (IMSIA - UMR 9219)
%+ Istituto di Scienze dell'Atmosfera e del Clima (ISAC)
%A Kebiri, S.
%A Maitournam, H.
%A Bourgeois, M.
%A Di Paola, F.
%< avec comité de lecture
%B World Congress of Computational Mechancis (WCCM)
%C New York, United States
%8 2018-07-22
%D 2018
%K Ductile fracture
%K modelling
%Z Physics [physics]/Nuclear Experiment [nucl-ex]
%Z Physics [physics]/Nuclear Theory [nucl-th]Conference papers
%X The simulation of crack propagation in ductile materials using the finite element method requires appropriate models for describing the nucleation, growth and coalescence of voids in a robust way. Local models, such as Rousselier and Gurson-Tvergaard-Needleman are now available in the finite element softwares as Cast3m [3]. A large number of models of this kind can be found in the literature, but they suffer from numerical drawbacks. First, they often show a marked mesh dependency of the solution. Second, volumetric locking of the elements is common in elastoplastic damage models in near-incompressible conditions. These two major issues must be solved in order to insure the robustness of such approaches. Our goal is to propose a model which be able to handle these two problems. The mesh dependency can solved by using regularization techniques, such as implicit gradient enrichment of an internal variable [1]. The locking can be treated, either using selective integration techniques, or a mixed formulation [2], which adds the volume variation as a new variable in addition to the displacement.The proposed models, based on the existing Rousselier and GTN models in Cast3m [3], address both issues using an implicit-enriched gradient of damage, and include a mixed formulation in the local models to ensure the desired robustness. In this presentation, the new models and the implementation of the new models are first presented. In a second part, simulations of crack propagation using the proposed models for axisymmetric and compact-tensile specimens in 2D using the Cast3m finite element software [3] are used to illustrate the relevancy of the approach.
%G English
%L cea-02339301
%U https://cea.hal.science/cea-02339301
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%~ UNIV-PARIS-SACLAY
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