Issue 38

C. Gourdin et alii, Frattura ed Integrità Strutturale, 38 (2016) 170-176; DOI: 10.3221/IGF-ESIS.38.23 170 Focussed on Multiaxial Fatigue and Fracture Equi-biaxial loading effect on austenitic stainless steel fatigue life C. Gourdin CEA, DEN, DM2S, SEMT, LISN, F-91191 Gif-sur-Yvette, France, cedric.gourdin@cea.fr S. Bradaï, S. Courtin AREVA NP SAS, Tour AREVA, F-92084 Paris La Défense, France. J.C. Le Roux EDF, R&D, Site des Renardières, F-77818 Moret sur Loing Cedex, France. C. Gardin Institut Pprime, CNRS-ENSMA UPR 3346 BP40109, F-86961 Futuroscope Chasseneuil Cedex, France. A BSTRACT . 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 are available on austenitic stainless steels. It is essential to improve the fatigue assessment methodologies to take into account the potential equi-biaxial fatigue damage. Hence this requires obtaining experimental data on the considered material with a strain tensor in equi- biaxial tension. Two calibration tests (with strain gauges and image correlation) were used to obtain the relationship between the imposed deflection and the radial strain on the FABIME2 specimen. A numerical study has confirmed this relationship. Biaxial fatigue tests are carried out on two austenitic stainless steels for different values of the maximum deflection, and with a load ratio equal to -1. The interpretation of the experimental results requires the use of an appropriate definition of strain equivalent. In nuclear industry, two kinds of definition are used: von Mises and TRESCA strain equivalent. These results have permitted to estimate the impact of the equibiaxiality on the fatigue life of components. K EYWORDS . Design fatigue curve; Equibiaxiality; Experimental device; Austenitic steel. Citation: Gourdin, C., Bradaï, S. Courtin, S., Le Roux, J.C., Gardin, C., Equi-biaxial loading effect on austenitic stainless steel fatigue life, Frattura ed Integrità Strutturale, 38 (2016) 170-176. Received: 12.05.2016 Accepted: 14.06.2016 Published: 01.10.2016 Copyright: © 2016 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.