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Auteur / Autrice : Thomas Sayet
Direction : Jean-Michel BergheauEric FeulvarchJean-Baptiste Leblond
Type : Thèse de doctorat
Discipline(s) : Mécanique et ingénierie
Date : Soutenance en 2014
Etablissement(s) : Ecole nationale d'ingénieurs (Saint-Etienne ; 1961-....)

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Résumé

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Welding with material fusion is a high temperature joining process widely used in the industry. The development of a simulation software able to reproduce the distortion and residual stresses must take into account the complexity of this multi-physical process. The work of this thesis is part of an ANR project entitled SISHYFE "simulation of hybrid welding of large thicknesses". In this thesis, we propose a numerical simulation tool of the arc welding process. We model the material in its solid state in a Lagrangian formulation and its liquid state in an ALE approach. The transition between the two states during heating and cooling is ensured in a "continuous" way using a specific behaviour law. This model brings three important points. The first point is the development of a solid tetrahedron linear finite element formulated in velocity/pressure. This element ensures results free of volumetric locking and a significant calculation time saving. The second point concerns the modeling of the surface tension effects, precisely the tangential effects known as "Marangoni flow" and the normal effects or "curvature effects". The last point is a behaviour law based on a parallel and series model. Several examples are presented in the chapters of this manuscript. The results are compared with analytical solutions in order to judge the ability of the tool to reproduce these results.