PSI - Issue 75

20

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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5.1. Details of a reference case fatigue test One small-sized i-Clip was tested under a tension load of 70 kN ± 50 kN, with an initial preload of 160 kN. This solicitation is equivalent to 7,000 kN +/-5,000 at scale 1. A total of 2,643,069 cycles were completed to observe crack propagation. By the end of the test, the crack length visible on the surface had reached 10 mm (Fig. 15).

Fig. 15: Lug 1 fracture surface of small-sized prototype, male part

• Strain gauges analysis Crack initiation can be detected at an early phase, even before it becomes observable through magnetic particle testing. The crack initiation signature on Lug No. 1 can be identified using the strain gauge. This is initially evident in the average strain value, which began to increase after 1,600,000 cycles (Fig. 16).

Fig. 16: Average strain values on lug n°1