PSI - Issue 66

Ramdane Boukellif et al. / Procedia Structural Integrity 66 (2024) 55–70 Ramdane Boukellif et al. / Structural Integrity Procedia 00 (2025) 000 – 000

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Fig. 20. Measured residual stress curve in the outer ring (M50Nil) and the residual stress curve used to simulate crack growth under rolling contact fatigue (Boukellif et al. (2024)).

Fig. 21. (a) Notch in the outer ring to take into account the complex load situation (b) modelling of the residual stresses in the circumferential direction by thermal stresses in the simulation model and in the area relevant for the crack growth simulation without a crack for outer ring. To compare the results of the crack path with the crack growth in the real tests, the crack in the real tests is divided into two regions I and II, as shown in Fig. 22. In the first part I the crack grows inclined inwards. After the cracks have reached a certain depth, their growth direction changes in part II. The predicted crack paths showed good agreement with only some tests. The calculated crack path with an initial crack length of 1.5 mm was compared with the resulting crack in the outer ring made of M50Nil. The predicted crack path agrees very well with the crack path in the real test. To determine the direction of further crack growth in part II, the maximum principal stresses are evaluated in Fig. 22. This shows that there is a high loading in the remaining cross section. This loading situation can lead to the complete fracture of the remaining cross-section due to strength failure. In this case, sharp kinking of the crack is very likely. The quantitatively expected direction of further crack growth in area II is shown Fig. 22.