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Theses

Étude numérique de la nocivité des défauts dans les soudures

Abstract : Defects can be formed during assembly processes such as welding and additive manufacturing. Current non-destructive inspection techniques are able to detect these voids in a mass production context. Thus there is a critical need of methods able to assess the harmfullness of these defects. These methods must be reliable to derive acceptation criteria. Their application in a industrial context requires efficiency to give an answer in a short time. This work aims at proposing an innovative design methodology that takes these defects into account. This work focuses on a particular welded joint : two titanium alloy parts are assembled by means of a pulsed laser. Three main topics are adressed. First, the cyclic behavior of the fusion zone is studied and modeled. X-Ray tomography is used to characterize the defects formed by the process. Their morphology is studied and a library of defects is built. The spatial distribution of the defects is closely linked to the welding process. A quantitative analysis provides a model able to generate realistic defect populations. To decrease the computational cost of numerical simulations of structures with defects, a model order reduction technique is proposed. It relies on the hyper-reduction method. A multi-scale reduced order basis building enables the use of data coming from tomographic analysis. Moreover, the offline phase cost is decreased.
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  • HAL Id : tel-02512870, version 1

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Laurent Lacourt. Étude numérique de la nocivité des défauts dans les soudures. Matériaux. Université Paris sciences et lettres, 2019. Français. ⟨NNT : 2019PSLEM050⟩. ⟨tel-02512870⟩

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