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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7. Conclusion This study presented a comprehensive FE methodology for analyzing the fatigue behavior of gear pairs in high performance automotive applications. The proposed workflow involved detailed discretization using HyperMesh, followed by model definition and simulation in MarcMentat. The initial goal was to validate the numerical model through a simplified simulation focusing on the first reduction stage. Upon successful validation, a parametric fatigue analysis was carried out to evaluate the influence of time step resolution on result accuracy and computational efficiency. A time step of 220 increments, corresponding to a 0.1° angular resolution, was identified as the optimal compromise. Subsequent simulations progressively introduced model complexity. The first refinement incorporated both shafts and updating boundary conditions. While the quasi-static response remained similar to the initial configuration, stress levels increased at the tooth root due to the revised boundary condition, now applied at the bearing locations. The model was further enhanced with the inclusion of bearing stiffness, simulated using spring elements on each side of the shaft. This addition led to slight modifications in contact behavior, accompanied by a reduction in localized pressure and stress. The influence of the second-stage reduction load was also integrated, producing minor shifts in the contact pattern due to global system deformation. The final enhancement involved the introduction of gear micro-geometry. As expected, this resulted in a centering of the contact area, with a corresponding redistribution of pressure and stress. Notably, the inclusion of micro geometry provided more accurate predictions of the most critically stressed zones and highlighted its beneficial effect on noise and vibration characteristics, and a localized increase in the safety factor. Overall, the proposed methodology effectively captures the influence of successive model refinements on contact mechanics, stress distribution, and fatigue life prediction. The final simulation represents the most accurate configuration, offering high fidelity in both qualitative and quantitative assessments. The proposed framework offers gear designers a powerful tool to push the boundaries of gear optimization by accurately assessing fatigue safety factors and enabling material reduction in the gear body. This contributes to lower mass and a decrease in associated performance losses, which are critical in high-efficiency applications. Furthermore, the study establishes a solid foundation for future research focused on enhancing gear design under realistic loading and operating conditions, integrating advanced simulation techniques with experimental validation. Acknowledgement This research project has received funding from “Progetti di formazione per la ricerca - Territorio: transizione tecnologica, culturale, economica e sociale verso la sostenibilità – 39° Ciclo RIF. PA 2023-19066/RER– Codice CUP: E83C23000510002”. References Bonaiti, L., Concli, F., Gorla, C., & Rosa, F. (2019). Bending fatigue behaviour of 17-4 PH gears produced via selective laser melting. Procedia Structural Integrity , 24 , 764–774. https://doi.org/10.1016/j.prostr.2020.02.068 Chen, Y.-C., & Tsay, C.-B. (n.d.). Finite Elements in Analysis and Design 38 (2002) 707-723 Stress analysis of a helical gear set with localized bearing contact . www.elsevier.com/locate/ÿnel Chen, Z., Zeng, M., & Fuentes-Aznar, A. (2020). 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