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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In these simulations, the friction between the crack surfaces and between the rolling elements and the surface of the hollow shaft is considered. The coefficients of friction used, radius of the rolling element, contact pressure and material parameters are described in Table 3.

Table 3: Parameters used for the prediction of crack path in the hollow shaft. Parameters Friction coefficient: cylinder/hollow shaft

0.15

Friction coefficient: crack surfaces Cylinder radius R Maximum contact pressure Inside radius Outside radius

0.15 9 mm 2400 MPa 32 mm 37.5 mm

The residual stresses in the hollow shaft made of 32CDV13 in Fig. 18 were considered in the rolling contact fatigue crack growth simulations. For this purpose, the residual stresses were measured in the circumferential direction, as shown in Fig. 16. The residual stresses in the hollow shaft were modelled by thermal stresses in the FE-model. Temperatures were specified for all node rings according to the measured residual stress curve, see Fig. 16. Because the measured residual stresses do not provide equilibrium on the FE-model used, the tensile residual stresses were calculated maintaining the measured compressive residual stresses, adjusting the residual stresses across the cross section to ensure equilibrium is reached, see Fig. 16 (dashed curve). This curve was used for crack growth simulations.

Fig. 16. Description of the measured residual stress curve in the hollow shaft (32CDV13) and the residual stress curve used to simulate crack growth under rolling contact fatigue (Boukellif et al. (2024)).

Fig. 17 (a) shows the calculation model under residual stresses, where the relevant area for the fracture mechanical evaluation is meshed much more finely (see Fig. 17 (b)). Next, a notch with a length of 1 mm in the radial direction is made in the model (see Fig. 17 (c)). The compressive residual stresses near the surface push the two edges of the notch together, whereby in the notch base the edges are pulled apart because of high tensile residual stresses (see