PSI - Issue 80

Simone Messina et al. / Procedia Structural Integrity 80 (2026) 232–243 Simone Messina/ Structural Integrity Procedia 00 (2019) 000–000

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Time step 55 Maximum Principal Value of Stress Node 353035 110 Maximum Principal Value of Stress Node 353035 220 Maximum Principal Value of Stress Node 353035 330 Maximum Principal Value of Stress Node 353035

Maximum principle value of stress

Fig. 8 Maximum principle value of stress in different time step simulations for Gear 2.

5. Fatigue analysis The fatigue analysis has been conducted only on the best set up among the four cases. More in detail, the fatigue analysis (Yang, 1996) has been performed on the teeth that has seen the full meshing operation using the Dang Van criterion (Dang Van - 1984 - Multiaxial Fatigue Limit, a New Approach), implemented through a Python-based code. The output of this analysis has provided a detailed distribution of the safety factor across all gear teeth, node by node, for both gears. Fatigue analysis results Fig. 9 and 10 show the results of the fatigue analysis. Only the fifth tooth has undergone the full fatigue cycle, and it is therefore the only area where the reader’s attention should be focused. Fig. 9 refers to the case without microgeometry, whereas Fig. 10 includes it. From the images, it can be observed that the minimum safety factor shifts from the tooth edge toward the center, mirroring the trends observed in the static analysis shown in Fig. 6 and confirming the well-known experimental evidence on the beneficial effects of applying an appropriate microgeometry. Table 2 numerically reports the lowest safety factor for each gear. An increase of 2 % is observed in the case with microgeometry. This behavior has been attributed to the fact that the contact area is no longer affected by stress concentration and they are distributed along the entire tooth surface. While this contact distribution offers substantial benefits in terms of vibration damping and noise reduction, thanks to the introduction of micro-geometry, it also results in an increase of the overall safety factor. 5.1