High cycle multiaxial fatigue crack initiation : experimental observations and microstructure simulations

Komlan Agbessi (1) , Nicolas Saintier (1) , Thierry Palin-Luc (1)

1 I2M - Institut de Mécanique et d'Ingénierie de Bordeaux

This study provides an analysis of high cycle multiaxial fatigue crack initiation modes based on SEM observations.The statistical study of crack initiation preferential sites shows that grains with multiple slip have a high probability of crack initiation. The application of Dang Van criterion at the grain scale using finite element analysis (cubic elasticity with / or without crystal plasticity) on 3D synthetic semi-periodic microstructures shows a strong heterogeneity of both the hydrostatic stress and shear. The evolution of this heterogeneity introduced by the material behavior is discussed. Finally, a method based on the extreme values statistics is proposed and applied to the fatigue indicative parameter associated to the Dang Van criterion. The effects of free surface and constitutive material model were analyzed.

Mots clés: high cycle multiaxial fatigue; crack initiation; extreme value statistic

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]

Komlan Agbessi, Nicolas Saintier, Thierry Palin-Luc. High cycle multiaxial fatigue crack initiation : experimental observations and microstructure simulations. Congrès français de mécanique (21 ; 2013 ; Bordeaux (Gironde))., Aug 2013, France. pp.1-6. ⟨hal-00906451⟩