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 9 In Fig. 12(b), the curves of for the initial crack with and without consideration of the residual stresses are calculated and compared. There was a clear difference between cracks that were also under residual stress. In this case, there is only one clear maximum value. That is, the crack is expected to grow towards the surface without branching, while the crack without residual stress may exhibit crack branching, with one crack branch growing into the surface and the other growing into the inner material. Fig. 12(b) also shows that the maximum value of the crack loading is higher due to the residual stresses. 63

Fig. 12. (a) Distribution of residual stresses without rolling contact; (b) at the initial crack under rolling contact (Boukellif et al. (2024)). The crack path with consideration of residual stresses was compared with the crack path without residual stresses, as shown in Fig. 13. For this comparison, only the crack path (without residual stresses) in the direction of the surface was considered. Here, it can be clearly seen that the residual stresses have no influence on the crack path with these selected parameters and boundary conditions. Since the crack grows after kinking mainly under Mode I loading, values were calculated for the two crack paths in Fig. 13(b) and compared. While the crack stops in the half-plane without residual stresses ( close to ℎ =150 N/mm 3/2 ), the crack can grow taking into account the residual stress.