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. 17 (d)).

Fig. 17. Modelling of residual stresses by thermal stresses, (a) distribution of residual stresses in the cross section of the raceway, (b) distribution of residual stresses in the cross section without notch, (c) adding the notch in the raceway and (d) influence of residual stresses on the notch (Boukellif et al. (2024)). The crack growth simulations are compared with the experimental tests. For the tests a hollow shaft with a laser scratch was used (see Fig. 18).

Fig. 18: Consideration of the complex load situation: nitride hollow shaft (32CDV13) for testing with laser scratch 704 µm.

The predicted crack path and the crack growth in the test of the hollow shaft are shown in Fig. 19. The crack in the simulation grew straight from the notch in the radial direction without crack branching, as shown Fig. 19 (a). A comparable crack propagation from 1 mm, as indicated by the red line (starting from the laser scratch) can be observed in Fig. 19 (b), whereby a crack network also formed during the test and the presence of any crack propagation in to the depth from the bottom of laser scratch, as indicated by the red line, is questionable. It was predicted by the simulation that the crack would continue to grow due to high tensile residual stresses until total failure of the hollow shaft. The cracks only grew slightly deeper in the real tests. The resulting crack networks on the surface next to the notch were probably due to the influence of the white layer. This assumption requires further study (Boukellif et al. (2024)).