Wear characteristics of three-lobe semi-floating ring bearings during start-up based on the energy model

Purpose The cumulative wear of three-lobe semi-floating ring bearings (SFRBs) in marine turbochargers significantly limits their service reliability. This study aims to predict the unsteady wear evolution during frequent start-stop cycles and propose optimization strategies. Design/methodology/approach A transient lubrication-wear coupled model integrating the energy dissipation principle, asperity contact mechanics and temperature-viscosity effects was established. The model’s accuracy was validated through high-fidelity bench tests and microscopic characterization. Findings The study reveals that the “Edge Effect” driven by fluid end-leakage is a primary wear mechanism. Results indicate that the axial “deep ends, shallow middle” wear distribution is a persistent physical constraint that does not improve with the running-in process. Experimental measurements confirm that wear depths at the edge regions (>16 µm) exceed the sacrificial coating thickness (11.5 µm), causing substrate exposure. Furthermore, a trade-off between rotor dynamic stability and tribological performance is identified; notably, start-up modes with high initial acceleration (e.g. Inverse Sigmoid) are proven to reduce cumulative wear significantly. Originality/value This paper clarifies the boundary between surface running-in and coating depletion for three-lobe bearings and provides a theoretical basis for optimizing start-up control strategies to extend bearing life.