Model reduction strategy applied to a problem of crack propagation in anisotropic materials
Résumé
Fatigue affects components subjected to cyclic loadings such as high pressure turbine blades that work in aggressive environments. In order to predict their life, a damage tolerance approach must be set. This approach requires a study of crack propagation and encounters two main problems. The first one is the non linear behavior of the material (Nickel base super-alloy) especially under complex loadings where the definition of a cycle is no longer obvious. The second problem is running long and expensive elastic-plastic finite element computations on complex 3D structures over millions of cycles. In order to overcome the first problem an incremental model was proposed. It's mainly based on the blunting of the crack tip and hence the crack propagates due to plasticity. To address the second problem a model reduction strategy was used to reduce the cost of finite element analysis while taking into account the anisotropy of single crystals.