PSI - Issue 57

Yuri Kadin et al. / Procedia Structural Integrity 57 (2024) 236–249 Kadin et. al / Structural Integrity Procedia 00 (2023) 000 – 000

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integral method cannot be used for the SIF evaluation, hence it is computed from the crack tip displacement (see e.g. Zolotarevskiy et. al (2020)).

x

y

z

Fig. 8: Local tension at the roller chamfer; no imperfection is present.

Recall, that RCF belongs to multi-axial fatigue, meaning that the crack front can be simultaneously subjected to all three modes: the shearing modes and the opening mode K I . Note, that the last mode is typically suppressed in the rolling contact conditions due to compression, however in some cases K I can get active. In the current problem, the tension can locally developed at the roller edge (see Fig. 8), meaning that K I should be also included into the RCF analysis. Note, that the distribution of tensile stress  xx , presented in Fig. 8, is not symmetric, but gets higher behind the contact zone which is associated with surface traction. This traction is resulted by the surface friction, which in the current work is also modelled with the Coulomb law, assuming the friction coefficient of 0.05 (corresponding to satisfactory lubrication conditions).

Raceway

Fig. 9: Modelling of a crack at the roller chamfer.