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Sur une approche pragmatique de l’endommagement anisotrope par fatigue basée sur un critère de fatigue et ses gradients

Sujet: Damage, Fatigue, Failure, Cracks, Damage propagation, [SPI.MECA]Engineering Sciences [physics]/Mechanics [], [SPI.GCIV]Engineering Sciences [physics]/Civil Engineering
Auteur: Manai, Asma
Résumé: A new practical engineering methodology for the analysis of structures undercyclic loading is proposed in this work. A new anisotropic fatigue damage model isdeveloped. The evolution of material properties degradation depends on a failure criterion andits gradient. The anisotropic material degradation will guide the damage propagation. Thepropagation of damage is mainly depending on the ridges of the criterion’s “surface” (zerogradients). The proposed approach can describe the initiation and propagation of the damageuntil the structural failure under fatigue loading. For each finite element, non-homogeneousanisotropic distributions of material properties are associated. Schematically, it seems like amaterial “surfing” on the criterion’s “surface” and damages follow the crest of the criterion’s“surface” (level and gradient). A global approach criterion, based on invariants of the stresstensor, is adopted. The reduction of material properties is assigned to a number of cycles anda global level of stresses, using an experimental Wöhler curve.Two simplified forms of the model are proposed and results are compared with a cruciformexperimental reference example and an industrial case. A mapping with Dang Van criterion isalso computed to analyze the numerical results
Editeur: HAL CCSD