Failure Case Study Series Part Three: Investigation of Wear and Failure Mechanisms in Heavy-Duty Gear Coupling
Abstract
This paper investigates the failure mechanisms of the gear teeth in a heavyduty coupling, emphasizing the combined effects of mechanical loading, metallurgical microstructure, and tribological wear mechanisms.
Detailed characterization using optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and both chemical and mechanical testing identified pronounced wear and progressive degradation of the coupling sleeve, largely driven by operational misalignments and external contamination, such as mill cobbles. The analysis underscores the critical importance of precise material compatibility, a controlled hardness differential, and manufacturing accuracy in mitigating localized stress concentrations and wear. The findings highlight that abnormal wear progression results from a complex interaction among load redistribution owing to misalignment, tribological deterioration, manufacturing tolerances, and dynamic rotor–coupling interactions. Recommendations focus on optimizing design parameters, manufacturing processes, and operational routines to enhance the reliability, durability, and safety of high-torque coupling systems in harsh industrial environments.
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References
[2]. Miao X., et al., Dynamic characteristics of rotor system with parallel and angular misaligned involute spline coupling, Meccanica, 59, p. 1061-1085, 2024.
[3]. Wang J., et al., An accurate finite element model for tooth contact and meshing force distribution of crown gear coupling, Journal of Mechanical Science and Technology, 39(5), p. 2767-2778, 2025.
[4]. Zhang C., et al., An improved dynamic model of the spline coupling with misalignment and its load distribution analysis, International Journal of Mechanics and Materials in Design, 20, p. 393-408, 2024.
[5]. Jangra D., et al., Gear sliding wear: The role of radial, axial, and combined misalignment, Journal of Mechanical Science and Technology, 39, p. 5375-5383, 2025.
[6]. Zhao Y., et al., A lubrication contact pair model for simulating gear micro pitting damage characteristics based on contour integral, Advances in Mechanical Engineering, 13(8), p. 1-9, 2021.
[7]. Li Z., et al., Nonlinear dynamics of unsymmetrical rotor bearing system with fault of parallel misalignment, Advances in Mechanical Engineering, 10(5), p. 1-17, 2018.
[8]. Wang J., et al., Finite element analysis of gear tooth root crack under misalignment, The Journal of Engineering, (In press), https://doi.org/10.1049/joe.2018.9209, 2025.
[9]. Iñurritegui A., et al., Spherical gear coupling design space analysis for high misalignment applications, Mechanism and Machine Theory, 173, 104837, 2022.
[10]. Guan Y., et al., Clearance distribution and contact characteristics considering hob feed path in misaligned gear couplings, Scientific Reports, 15, p. 1-16, 2025.
[11]. de Bechillon N. G., et al., A new experimental methodology to assess gear scuffing initiation, Tribology-Materials, Surfaces & Interfaces, 16(3), p. 245-255, 2022.
[12]. Jangra D., et al., Gear sliding wear: The role of radial, axial, and combined misalignment, Journal of Mechanical Science and Technology, 39, p. 5375-5383, 2025.
[13]. Olson R., et al., Case study of ISO/TS 6336 22 micropitting calculations, Proceedings of the NREL/CP 5000 77731, 2020.
[14]. McCormick M., Scuffing. Gear Solutions Magazine, Retrieved from https://gearsolutions.com, 2016.
[15]. Gurau L., Failure Case Study Series Part One: Analysis of Oxygen Compressor Shaft Breakage, The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science, vol. 49, no. 1, p. 11-18, 2026.
