The incident of the Civaux Ⅰ pewer plant as some works in thermal fatigue have disproved current methodologies and usual criteria to predict propagation when components are submitted to thermal fatigue. Improvements in analytical methodologies and new experimental data are required to get better assessments of crack propagation under thermal fatigue.As part of this work, a new thermal fatigue test, Fat3D, has been developed to study the problem of fatigue crack growth under thermal fatigue conditions on AISI 304L quasi-structure specimens. The importance of the initiation and the propagation phases on a notched specimen and the evolution of the stress intensity factor according to the propagation were also investigated. This experimental campaign has also been completed by a characterisation campaign on the AISI 304L material and by a benchmark of different non destructive techniques to detect and follow crack propagation. In parallel, numerical analyses have been developed using the French finite element code of the CEA, Cast3M. This combined experimental and numerical study enables to evaluate the proposed improvements in analytical methods to accurately predict crack growth under thermal loadings and to understand the influence of the main parameters concerning crack propagation in such components.
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