PSI - Issue 75

Fabrice Deleau et al. / Procedia Structural Integrity 75 (2025) 392–418 Deleau Fabrice, Emmanuel Persent, Guillaume Coudouel, Guillaume Perrin/ Structural Integrity Procedia (2025)

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Fig. 24: Activity recorded on small-sized i-Clip 987 - 2,444,559 to 2,643,069 cycles - Left: Energy versus time with cracking filter - Right: Energy versus time

To enable better visualization of the end-of-test activity, the EA files were concatenated (Fig. 25) and the cumulative cracking activity represented for both lugs. This EA activity was compared with the evolution of IFPEN strain gauges on the same test.

Fig. 25: Cumulative cracking activity recorded on small-sized i-Clip 987 - Time intervals without cycling are included in the graph, explaining the difference in size of the cycling intervals.

The graph above highlights the sharp acceleration in damage observed from around 2,050,000 cycles, and a fortiori the significant increase observed around 2,445,000 cycles. We also note the higher proportion of activity coming from lug No 1, with around twice as much activity recorded at the end of the test on this lug. Activity on lug No 2 increases significantly at the very end of the test, at around 2,545,000 cycles. These results are entirely consistent with the phenomena observed on the deformation gauges (Fig. 18), which also show an acceleration in the deformations recorded on both lugs at around 2,000,000 cycles, as well as a slight stalling of certain gauges on the rear lug at around 2,500,000 cycles. IFPEN decided to definitively stop the test after 2,643,069 cycles and perform dye penetrant testing on the two lugs of the assembly. It should be noted that the results of this penetrant test were not provided to Institut de Soudure prior to presentation of their preliminary conclusions.