PSI - Issue 75

D. Jbily et al. / Procedia Structural Integrity 75 (2025) 158–175 Author name / Structural Integrity Procedia (2025)

161

4

REF Pinion (65.5 hours)

SP Pinion (239 hours)

Fig. 2. View of

the flanks at the end of the tests

Profile measurements showed that SP gears experienced a significantly faster initial wear compared to the unpeened reference (REF) teeth. After just 18.5 hours, the SP tooth exhibited a profile loss of approximately 11 μm, the same amount of wear observed on the REF tooth after approximately 65.5 hours (see Fig. 3). Between 18.5 and 139 hours, the SP tooth underwent an additional profile loss of about 11 μm over 120 hours, indicating slower wear rate following the initial phase. This wear pattern suggests that the SP tooth experiences two distinct wear rates: a rapid initial loss within the first 18.5 hours, followed by a slower rate until 139 hours. This behavior may be attributed to surface conformity established during the initial hours of operation under nominal load. Such conformity could manifest at two scales: micro-geometric evolution at the roughness scale and macro-geometric evolution at the contact scale. However, further testing and investigation are necessary to validate these hypotheses. However, further testing and investigation are necessary to confirm these assumptions.

Fig. 3. Profile loss comparison ISO 6336-22:2018 calculations predicted a higher theoretical safety factor against micropitting in SP gears ( Fig. 4 ), despite the fact that these teeth exhibit more micropitting damage.