Développement d'un modèle analytique pour l'analyse en élasticité linéaire de champs de déformation et contrainte au sein d'un polycristal. comparaison avec la méthode des éléments finis

Abstract

Fatigue damage of materials is a common problem in many areas, including aeronautics. To prevent fatigue failure of materials it is necessary to determine the fatigue lives. Unfortunately, due to the presence of heterogeneities, two identical parts made of the same materials having undergone the same processing can have different fatigue lifes. Therefore these heterogeneities should be considered in our models in order to have a better estimate of the fatigue life of materials. As a first step towards a better consideration of heterogeneities in our models, a study in linear elasticity of the influence of crystallographic orientations on the strain and stress fields in a polycrystal was performed using the finite element method. Correlations have been established from the results, and an analytical model in linear elasticity taking into account the distributions of crystallographic orientations and neighborhood effects was developed. This model is based on conventional homogenization models, such as self-consistent model, and also incorporâtes the neighborhood principles of cellular automata. Taking as reference the results of finite element analysis, the analytical model here developed has shown to have an accuracy twice bigger than the self-consistent model, regardless of the material studied.

Date	14 Mar 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Philippe Bocher (Supervisor)