A multiaxial life prediction method applied to a sequence of non similar loading in high cycle fatigue

This paper shows how an original critical plane high cycle multiaxial fatigue life prediction method can deal with sequential application of nonsimilar loading. In this mesoscopic damage model, the plastic strain accumulated at the scale of the grain is considered the damage variable. Two load conditions are said to be similar if they present the same fatigue limit according to a proper multiaxial endurance criterion. It is more specifically detailed how the successive applications of a torsion loading and a tension loading can lead to interaction mechanisms between microcracks. The critical plane fatigue damage model is applied to the block sequence with two different damage interaction assumptions. It leads to an upper bound and a lower bound of fatigue life prediction which are compared to fatigue tests under a sequence of tension and torsion carried out on a mild steel.