PSI - Issue 57

Stéphan Courtin et al. / Procedia Structural Integrity 57 (2024) 4–13 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Crack growth direction

Fig. 8. Evolutions of the numerical freecrack fronts in thethickness ofthe mock-up, for the so-called F4 crack, with the thermal loading #1, with a semi-elliptical initial crack front (a) and with a straight initial crack front (b).

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Fig. 9. Numerical andexperimental crackgrowths for theso-called F4crack, with thethermal loading #1, on the bottom face of the mock-up with a semi-elliptical initial crack front (a) and with a straight initial crack front (b). 6. Comparisons between numerical results and experimental data for the thermal loading #2 Similar numerical analyses have been performed for the thermal loading #2 which generates fatigue cracks propagating only on the bottom face of the mock-up, and whose experimental results have never been reported before. Free crack fronts are here considered in the thickness of the mock-up, with a straight initial crack front. The ‘shifted RCC - MRx’ option, and the mean PWR water environment law, have been chosen , respectively, for the cyclic elastic-plastic stress-strain curve, and the codified crack growth Paris law. Fig. 10 (a) illustrates the evolution of the numerical crack fronts for a given crack of the test. The experimental trend giving fatigue cracks propagating only on the bottom face of the mock-up, is well captured. Fig. 10 (b) shows a good agreement between the numerical results and the experimental data on the bottom face of the mock-up. Here the margin on the number of cycles to reach the final experimental crack length, is approximately 3.5.