Issue 38

C. Gourdin et alii, Frattura ed Integrità Strutturale, 38 (2016) 170-176; DOI: 10.3221/IGF-ESIS.38.23 174 The first fatigue test campaign is performed on austenitic stainless steel type 316L. Five levels of deflection are studied: 1.6 / 1.4 / 1.2 / 1.1 and 0.9 mm. a) propagation of crack at 16500 cycles b) propagation of crack at 22000 cycles Figure 4: Image from the camera 2 (side 2) (a) and from the camera 1 (side 1) (b). In the frame of CEA-EDF-AREVA working group, a second fatigue test campaign is performed on austenitic stainless steel 304-CLI provided by EDF. This material completely agrees with the RCC-MRx [9] and RCC-M [10] specification. Three levels of deflection are carried out 1.4 / 1.3 and 1.2 mm. I NTERPRETATION OF THE EXPERIMENTAL RESULTS ll tests performed in this study are carried out with imposed displacement (strain) with alternating load (without mean stress or strain), means with a stress ratio R=-1. To compare the experimental data obtained from uniaxial and equibiaxial tests, it is necessary to define a total equivalent strain. Two definitions of equivalent strain are proposed: the first is based on the definition of von Mises (used in the RCC-MRx) and the second on the definition of TRESCA (used in the RCC-M, RSE-M). 0,000 0,100 0,200 0,300 0,400 0,500 0,600 0,700 0,800 0,900 1,000 1000 10000 100000 1000000 10000000 100000000 Equivalent Strain (%) Cycles Number 316L von Mises 316L Tresca Uniaxiale 316L 304CLI von Mises 304CLI Tresca Uniaxiale 304CLI  /2 Figure 5: Austenitic stainless steel fatigue curve for 304L-CLI and 316L under uniaxial and equibiaxial loadings A