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As the crucial support component of the propeller power system, the reliability of the operation of submersible pumps is influenced by the lubrication performance of water-lubricated thrust bearings. When the water-lubricated thrust bearings are under start-stop or heavy load conditions, the effect of surface morphology is crucial as the mixed lubrication regime is encountered. This paper aims to develop one mixed lubrication model for the water-lubricated thrust bearings to predict the effects of surface skewness, kurtosis and roughness orientation on the loading carrying capacity and tribological behavior.

This paper developed one improved mixed lubrication model specifically for the water-lubricated thrust bearing system. In this model, the hydrodynamic model was improved by using the height of the rough surface and its probability density function, combined with the average flow model. The asperity contact model was improved by using the equation for the Pearson system of frequency curves to characterize the non-Gaussian aspect of surface roughness distribution.

According to the results, negative skewness, large kurtosis and lateral surface pattern can improve the tribological performance of water-lubricated thrust bearings. Optimizing the surface morphology is a reasonable design method that can improve the performance of water-lubricated thrust bearings.

In this paper, one mixed lubrication model specifically for the water-lubricated thrust bearing with the effect of surface roughness into consideration was developed. Based on the developed model, the effect of surface morphology on tribological behavior can be evaluated.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2023-0247/

This paper aims to study the startup performance of thrust bearing. The effects of acceleration scenarios, roughness, the area ratio of texture and texture depth on the transient startup performance of the thrust bearing were analyzed.

The lubrication model is solved by the Reynolds equation with the mass-conservation boundary condition. The Greenwood and Tripp contact model is used to predict asperity contact load. The finite volume method is used to discretize the governing equations.

By studying the bearing performance with different acceleration functions, it was found that the higher the acceleration at the beginning of the startup, the faster the thrust bearing operates under the hydrodynamic lubrication regime in the start stage. It appears that the friction and contact time of asperity increase with the increasing roughness. The optimal area ratio of texture is within 30%–50%. The depth of texture ranging from 1 to 2 is the best.

This paper proposes a transient mixed lubrication analysis model of the thrust bearing. This model can be used to analyze the variations of tribological performance and lubrication regime of the thrust bearing under different acceleration scenarios.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2022-0268/

This paper aims to investigate the gear performance during meshing. The effects of line load, velocity and rough surfaces (kurtosis and skewness) on the lubrication characteristics and fatigue life of gears were analyzed.

In the mixed thermoelastohydrodynamic lubrication (TEHL) model, the distributions of pressure and film thickness are predicted using the Reynolds equation. The elastic–plastic rough contact model is used to calculate the contact force and area. To predict the fatigue life of the gears, the Dang–Van fatigue model is used to obtain the fatigue parameters under different line loads, velocities and rough surfaces.

The skewness of rough surfaces has a more significant effect on gear performance. In addition, according to fatigue parameters, it is found that when the load is too large, it leads to an increase in the probability of gear failure.

In this paper, a mixed TEHL model considering the effects of kurtosis and skewness is developed for the line contact to predict the mixed lubrication problem during gear meshing.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2024-0356/

Surface coatings have been introduced on the contact surfaces to protect the mechanical parts for a long time. However, in terms of the optimum design of coatings, some key coating parameters are still selected by trial and error. The optimum design of coatings can be conducted by numerical experiments. This paper aims to predict the contact behavior of the coated rough surfaces accurately. One improved asperity contact model for the coated rough surfaces considering the misalignment of asperities would be developed.

Incorporating the coated asperity contact model into the improved Greenwood Tripp-based statistical approach, the proposed model can predict the elastic-plastic behaviors of the interacting coated asperities.

According to numerical experiments, compared with the coated asperity contact model in which an equivalent rough surface against a plane is assumed, the improved asperity contact model for the coated contacts can account for the effect of permitting misalignment of two rough surfaces. The contacts having the thicker, stiffer and harder coatings result in higher asperity contact pressure and smaller real contact area fraction under the given Stribeck oil film ratio.

In this paper, one statistical coated asperity contact model for two rough surfaces was developed. The developed model can consider the elastic-plastic behavior of interacting coated asperities. The effects of the coating thickness and its mechanical properties on the contact behavior of the rough surfaces with coatings can be evaluated based on the developed model.