Fast time-scale average for a mesoscopic high cycle fatigue criterion

Stefano Bosia (1, 2) , Andrei Constantinescu (1)

1 LMS - Laboratoire de mécanique des solides
2 Dipartimento di Matematica "F. Brioschi"

The paper discusses the lifetime prediction of structures in high-cycle fatigue based on the two-scale fatigue criteria of Dang Van type and several of its extensions in finite lifetime regime. The main assumptions for this criteria are (i) the material is polycrystalline and undergoes localised plasticity in one of the misoriented grains and (ii) crack initiation arises as a consequence of cumulated plasticity in this grain. The novelty of the presented approach is twofold. On the one hand a generalisation of mesoscopic plasticity model is presented, on the other a fast time scale average is introduced for tracking the cyclic material behaviour and the subsequent evolution of damage. The tracking method is based on the split between a quick quasi-periodic response of the system to the cyclic load and a slow evolution of the internal hardening and damage parameters of the material at the mesoscopic scale. The proposed method can be extended to a large class of local material behaviours involving not only plasticity, but also crack and damage evolution. The paper proposes a simplified plasticity-based model for the mesoscopic material behaviour and presents a comparison between predicted and experimental lifetimes. The results are discussed in terms of prediction capabilities and also in terms of the identification procedure of parameters of the mesoscopic model.

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

Stefano Bosia, Andrei Constantinescu. Fast time-scale average for a mesoscopic high cycle fatigue criterion. International Journal of Fatigue, 2012, 45, pp.39-47. ⟨10.1016/j.ijfatigue.2012.01.012⟩. ⟨hal-00761153⟩