Fatigue Life Assessment under Multiaxial Complex Loading

This paper aims at comparing two different modeling to assess the fatigue life of steel under complex multiaxial fatigue spectrum. The first model is based on a multiaxial fatigue criterion able to describe out of phase loading plus non-linear damage rule. The second one is based on an incremental mesoscale plasticity/damage modeling applied directly on the spectrum studied. Experimental results on 1045 steel are obtained under tension/torsion loading for out of phase variable loading spectrum representative of automotive chassis loading type. It is shown that the criterion with a non-linear damage rule is able to describe the experimental result for full spectrum (with overload) but the identification of the non-linearity is a function of spectrum type. The incremental approach gives better results for simplified spectrum (without overload) without any identification of the non-linearity of the damage.