Crack propagation in Large Scale Yielding (LSY) Conditions

In Industry, some components are subjected to fatigue thermal loadings due to thermal fluctuations coming from the meet of a cold and a hot fluid. A Large Scale Yielding (LSY) conditions zone can be created: plasticity is not only located at the crack tip, but extends to a larger area of the component. Thus, traditional hypothesis of elasticity cannot be used for numerical predictions. Nevertheless, crack propagation needs to be estimated with adapted numerical models.Thermomechanical fatigue crack propagation tests are performed with an EDF facility in the desired large scale yielding conditions. During the thermal fatigue tests, temperatures, strains and surface crack lengths are measured and registered. Microscopic analyses are carried out in order to observe the influence of the microstructure on the fatigue crack path.This paper presents first experiments performed with the PACIFIC test rig and first results get for crack propagation in Large Scale Yielding conditions.