Modélisation de la propagation des fissures courtes en fatigue dans le cas du 316L

Abstract

The experience demonstrates that the fatal crack is not necessarily the longest one taken at a given moment of the fatigue lifetime of a material, and it can be the result of other microcracks. Thus, the damage (by fatigue) is often related to the development and the growth of microcracks on the material surface. The advantage to consider a population of cracks as a physical factor of damage is that cracks' lengths and their number are quantifiable data which can be measured on the surface of material. The present work is driven in this sense and aims to characterize the damage and its evolution by the measure of the crack density on surface. A numerical model based on a probabilistic process concerning the nucleation of cracks, their propagation and their mutual interaction is proposed. It is then applied in the case of the 316L at ambient temperature and for plastic deformation equal to 8 × 10-3, 4 × 10-3 and 8 × 10-4. © AFM, EDP Sciences 2010.