How to reduce the duration of multiaxial fatigue tests under proportional service loadings

Thierry Palin-Luc (1, 2) , Alexis Banvillet (2) , Jean-François Vittori (3)

1 I2M - Institut de Mécanique et d'Ingénierie de Bordeaux
2 LAMEFIP - Laboratoire Matériaux Endommagement Fiabilité et Ingénierie des Procédés
3 Technocentre Renault [Guyancourt]

This paper deals with a technique to transform a multiaxial stress and strain-time sequence (in service recorded) in a simplified sequence. This simplified sequence is shorter than the original one and equivalent in terms of damage and lifetime: the number of simplified sequences to crack initiation is equal to the number of original sequences. The proposal is based on an energy threshold, below which no micro-crack can initiate or grow in the material. This technique was validated with real loading sequences recorded by strain gauges pasted on a car suspension arm. Fatigue tests were carried out on smooth specimens made of spheroidal graphite cast iron loaded in bending, in torsion and in combined bending and torsion. Experimental fatigue lives under the original sequence and under the simplified one are in very good correlation. Fatigue test duration is reduced up to a factor of 10 for the severe stress–strain sequences tested in this study.

Mots clés: Multiaxial fatigue; Accelerated fatigue test; Load sequence; Energy; Threshold; Variable amplitude

Domaines: Génie mécanique [physics.class-ph]; Mécanique des solides [physics.class-ph]

Thierry Palin-Luc, Alexis Banvillet, Jean-François Vittori. How to reduce the duration of multiaxial fatigue tests under proportional service loadings. International Journal of Fatigue, 2006, Selected papers from the 7th International Conference on Biaxial/Multiaxial Fatigue and Fracture (ICBMFF), 7th International Conference on Biaxial/Multiaxial Fatigue and Fracture, 28 (5-6), pp.554-563. ⟨10.1016/j.ijfatigue.2005.07.041⟩. ⟨hal-01373462⟩