CRACK INITIATION UNDER EQUIBIAXIAL FATIGUE, DEVELOPMENT OF A PARTICULAR EQUIBIAXIAL FATIGUE DEVICE

摘要

Fatigue lifetime assessment is essential in the design of structures. Under-estimated predictions may result in unnecessary in service inspections. Conversely, over-estimated predictions may have serious consequences on the integrity of structures. In some nuclear power plant components, the fatigue loading may be equi-biaxial because of thermal fatigue. So the potential impact of multiaxial loading on the fatigue life of components is a major concern. Meanwhile, few experimental data on austenitic stainless steels is available. It is essential to improve the fatigue assessment methodologies to take into account the potential equi-biaxial fatigue damage. For this reason, a new experimental data must be obtained on the considered material with a strain tensor in equi-biaxial tension. The aim of this paper is to present a new device "FABIME2" developed in the LISN in collaboration with EDF and AREVA. This new device allows accurate quantification of the effects of both equi-biaxial strain state as well as structure (such as mean stress) on the fatigue life. A Finite Element Modeling is also performed in order to obtain a precise description of the strain state in the specimen.