Stability of critical distance approach to predict fretting fatigue cracking: a “ℓ_opt – b_opt” concept

Camille Gandiolle (1) , Siegfried Fouvry (1)

1 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes

Fretting fatigue life prediction is a strategic issue for modern industry. Accurate prediction of total lifetime depends on crack nucleation time prediction. However, fretting fatigue is characterized by a high stress gradient which overestimates cracking risk at the hotspot. Hence non-local analyses are required. The present study focused on the critical distance method. However, no defined method is currently established to obtain this value, which has been shown to depend on microstructure or stress gradient. The present study investigated the influence of incipient crack length on critical distance crack nucleation prediction. An optimal ‘opt–bopt condition was introduced enabling accurate prediction of the crack nucleation condition whatever the loading condition. This approach was then applied to fretting endurance experiments, allowing to correlate fretting cracking endurance with shear fatigue data. Finally it was used on fretting fatigue lifetime experiments, showing good endurance prediction.

Mots clés: Critical distance; Stress gradient; Fretting fatigue; Lifetime prediction

Domaines: Mécanique des matériaux [physics.class-ph]

Camille Gandiolle, Siegfried Fouvry. Stability of critical distance approach to predict fretting fatigue cracking: a “ℓ_opt – b_opt” concept. International Journal of Fatigue, 2016, 82, part 2, pp.199-210. ⟨10.1016/j.ijfatigue.2015.07.016⟩. ⟨hal-01526059⟩