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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are presented in dimensionless form, being normalized by the selected threshold value,  K * . This threshold correspond to the resistance of Si3N4 to crack propagation, and the exact value of this parameter is not given for the sake of confidentiality. All three modes are normalized by the same  K * value, enabling to compare the criticality related to each of the modes.

Truncation peak

Pressure, [MPa]

y -coordinate, [mm]

Fig. 12: Pressure distribution along the y -coordinate at x =0 (see Fig. 1) for the roller of 11×12 mm. Due to the extreme loading conditions (high contact load + misalignment of 3(!) minutes) the contact load occupies 102% of the raceway

Crack size, b × d [  m] Crack orientation,  ° Crack location, S1 [  m] Loading conditions Crack faces friction,  Contact friction,  c Roller dimensions, D w × L [mm]

Fixed to 300×150 From ≈ 170 to ≈ 510 (depending on the orientation) Fixed to 11×12 Fixed to extreme conditions – see Fig. 11 0º (horizontal), 45º (inclined) and 90º (vertical)

Fixed to 0.7

Fixed to 0.05 Table 1: Summary of the parameters defining the RCF problem (satisfying the “worst case scenario”) .

 K II

 K III

 K /  K *

Crack front coordinate,  °

Fig. 13. Crack of vertical orientation (  =90 ° ): distribution of the dimensionless SIF ranges along the crack front. The data corresponding to the mode K I is not presented because for the crack of this ordination the opening mode is suppressed.