Diesel engine bearing liners are prone to mixed or local boundary lubrication during start–stop operation because the lubricant film is not fully established during start-up and can collapse during shutdown. This study develops a transient mixed-lubrication wear model coupling oil-film pressure, asperity contact, journal motion, and wear, and validates it using component-level start–stop tests on full-size bearing-liner specimens with the Archard wear coefficient taken as a nominal engineering value of k = 5 × 10⁻⁶ mm³∙N⁻¹m⁻¹ for the soft electroplated PbSn18Cu2 bearing-liner surface—it is not calibrated against the present wear measurements. The results show that wear accumulates mainly during the early start-up stage, while shutdown contributes relatively little. Wear severity is governed less by the maximum oil-film pressure than by the duration and intensity of asperity contact during the initial film formation. Under a load of approximately 9 kilonewtons (kN), repeated cycles between 0 and 600 revolutions per minute (rpm), and controlled reservoir oil temperatures of 30–90 °C, the measured wear loss decreases from 4.6 mg at 30 °C to 1.6 mg at 90 °C. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) (Philips, Eindhoven, The Netherlands) show more pronounced ploughing grooves, adhesive transfer, plastic deformation, and local spalling at lower reservoir oil temperature. These results indicate that under the present conditions, a higher reservoir oil temperature improves lubricant supply, reduces asperity-contact accumulation, and mitigates start–stop wear. The structural state and elemental composition of the contact zone are also modified by asperity interaction and are treated as a coupled factor in the interpretation of these results.

To predict the mass loss of grooved journal-bearing shells under varying operating conditions while reducing experimental effort, accelerated wear tests were conducted on a component-level journal-bearing test rig. The effects of load, rotational speed, and oil temperature were investigated, and the worn surfaces were characterized microscopically to elucidate the wear mechanism. A backpropagation (BP) neural network was trained on 42 mass-loss samples and evaluated using 18 additional samples. Candidate numbers of hidden-layer neurons were identified using an empirical relation and compared based on prediction performance. A genetic algorithm (GA) and the sparrow search algorithm (SSA) were then used to optimize the initial weights and biases of the BP network. Mass loss increased with load and oil temperature but decreased with rotational speed; all responses were nonlinear. After testing, the groove structure remained visible, while the lead-based overlay became thinner and underwent plastic flow. Pb and Sn were detected on the aluminum-alloy surface, suggesting transfer of overlay material during sliding. The mean absolute percentage error (MAPE) and coefficient of determination (R²) were 26.986% and 0.54552, respectively, for the conventional BP model; 8.436% and 0.9862 for the GA-BP model; and 2.6296% and 0.99714 for the SSA-BP model. For the present dataset, the SSA-BP model achieved lower prediction errors than the BP and GA-BP models and reproduced the variation in mass loss across the investigated operating conditions.

Abnormal wear is a major cause of crankshaft failure, and replacing worn crankshafts usually results in high maintenance costs. Electroplated alloy technology provides a promising and cost-effective approach for the surface repair of damaged crankshafts and the surface strengthening of new crankshafts. In this work, Fe-Ni-Co electroplated coatings with different Co contents were prepared, and the effects of Co content on the surface morphology, microstructure, mechanical properties, and tribological performance of the coatings were investigated. The results showed that Co incorporation improved the overall performance of the Fe-Ni-Co coatings. When the Co concentration in the bath was 7.5 g/L, the coating exhibited a relatively smooth surface, a moderately dense reticulated texture, and better wear resistance. Compared with the Co-free coating, the coating prepared at 7.5 g/L Co exhibited a 10.5% increase in hardness and a 25.4% reduction in wear rate. Under dry friction conditions, the dominant wear mechanisms were oxidative wear and abrasive wear, accompanied by slight adhesive wear. The enhanced mechanical and tribological properties were mainly attributed to the combined effects of solid-solution strengthening and grain-refinement strengthening. These findings provide useful guidance for the practical application of Fe-Ni-Co electroplated coatings in crankshaft surface repair.

The sliding bearing bears the load and the friction, and its wear resistance directly affects the reliability of the related equipment. After a long-term service, the sliding bearing will have surface wear defects and serious adhesive wear, causing damage to the equipment. In this paper, the wear and the failure behaviors of sliding bearings are investigated. Based on the component-level sliding bearing friction and wear testing machine, the wear and the seizure tests are carried out, and the wear and the seizure failure mechanisms of sliding bearings are respectively explored. The results show that the wear loss increases with the rise in the load and lubricating oil temperature yet decreases as rotational speed rises. The anti-seizure performance decreases with increasing press, velocity and lubricating oil temperature. The groove structure of the sliding bearing still remains after wear, and the edge of the ternary electroplating layer undergoes plastic flow, which adheres to the surface of the aluminum alloy and plays a role in reducing friction. After the seizure failure, the groove structure of the bearing is destroyed, and the Al layer is exposed; however, the coating elements still have block-like residues, which adhere to the surface of the aluminum alloy layer. This study can provide a rapid evaluation method for the research on the wear and seizure failure behavior of sliding bearings, and provide a helpful foundation for the improvement of the design.