S téphan Courtin

EDF R&D, ERMES, Palaiseau, France

Research engineer, with over fifteen years of working experience in fatigue in nuclear applications. Fatigue expert for Areva NP/Framatome between 2005 and 2018, now at EDF R&D


Austenitic stainless steel large nuclear components, with high thicknesses, may experience cyclic large scale yielding due to mechanical and thermal loadings during their service life. International codes and standards only provide inadequate and very conservative methods for dealing with the fatigue crack growth associated with this situation. Non-codified alternatives, such as ΔJ approaches reported in References [1] and [2], then appear to be good candidates for predicting fatigue crack growth beyond small scale yielding.

This paper aims to apply a ΔJ approach on the PACIFIC experiment permitting thermal fatigue crack propagation in large scale yielding conditions [3]. Numerical protocol and modelling assumptions will be detailed. Thanks to sensitivity analyses, a particular focus will be given on the choice of the cyclic elastic-plastic stress-strain curve. Comparisons between numerical results and experimental fatigue crack growth data will be finally provided and discussed.

[1] J. Li, O. Ancelet, A. Double and S. Chapuliot, Evaluation of fatigue crack propagation by ΔJ approach, in Proceedings of the ASME 2019 Pressure Vessels & Piping Conference

[2] K. Hojo and S. Kumagai, Fatigue crack growth prediction of a pipe with a circumferential surface flaw using ΔJ and reference stress method, in Proceedings of the ASME 2022 Pressure Vessels & Piping Conference

[3] G. Leopold, F. Curtit and S. Courtin, Thermal fatigue crack propagation in large scale yielding (LSY) conditions: PACIFIC experiment on a 316L quasi-structure, in Proceedings of the ASME 2017 Pressure Vessels & Piping Conference


Room 6Wednesday 29th November09:45-10:30Stéphan Courtin
Plenary session
6 - Application of a ΔJ Approach for Thermal Fatigue Crack Growth Assessment on the Large Scale Yielding PACIFIC Experiment
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