A mechanistic approach to the Kitagawa-Takahashi diagram using a multiaxial probabilistic framework

Etienne Pessard (1) , Daniel Bellett (1) , Franck Morel (1)

1 LAMPA - PMD - Laboratoire des Arts et Métiers ParisTech d'Angers - Procédés Matériaux Durabilité

The aim of this paper is to propose a flexible multiaxial modelling framework that is capable of combining two fatigue damage mechanisms so as to continuously describe the Kitagawa-Takahashi diagram. It is proposed that this diagram represents two distinct fatigue damage mechanisms: one associated with crack initiation (or microstructurally small cracks) and the other with crack propagation (or long cracks). It is further postulated that these damage mechanisms are more appropriately modelled using di erent fatigue criteria. A probabilistic modelling framework is proposed in which any two suitable fatigue criteria can be combined in order to simultaneously model both damage mechanisms and the transition between them. This framework is based on the weakest link hypothesis and results in a probabilistic Kitagawa-Takahashi type diagram.

Mots clés: Probabilistic Kitagawa-Takahashi diagram; Fatigue damage mechanisms; High cycle fatigue; Small crack problem; Defects

Domaines: Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]

Etienne Pessard, Daniel Bellett, Franck Morel. A mechanistic approach to the Kitagawa-Takahashi diagram using a multiaxial probabilistic framework. Engineering Fracture Mechanics, 2013, 109, pp.89-104. ⟨10.1016/j.engfracmech.2013.06.001⟩. ⟨hal-00875771⟩