A mathematical model for rolling/sliding line contacts in boundary and near boundary lubrication

Yu, Qingtao; Chang, L.; Jeng, Yeau-Ren

doi:10.1177/1350650115577115

Cited by 8 publications

(9 citation statements)

References 24 publications

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“…The simulation of mixed lubrication contacts has been the subject of much research, from early work using sinusoidal roughness features and non-Newtonian lubricant treatments in transient micro-EHL models [10, 11], to more recent developments which feature real, measured rough surfaces [12], applied under realistic conditions representative of gear contacts [13], in three-dimensional point contacts [14], and in more heavily mixed and even boundary lubrication conditions [15].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Micropitting Initiation in Real Rough Surfaces in a Micro-elastohydrodynamic Lubrication Regime

et al. 2018

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Micropitting is a form of surface fatigue damage that happens at the surface roughness scale in lubricated contacts in commonly used machine elements, such as gears and bearings. It occurs where the specific film thickness (ratio of smooth surface film thickness to composite surface roughness) is sufficiently low for the contacts to operate in the mixed lubrication regime, where the load is in part carried by direct asperity contacts. Micropitting is currently seen as a greater issue for gear designers than is regular pitting fatigue failure as the latter can be avoided by control of steel cleanliness. This paper describes the results of both theoretical and experimental studies of the onset of micropitting in test disks operated in the mixed lubrication regime. A series of twin disk mixed-lubrication experiments were performed in order to examine the evolution of micropitting damage during repeated cyclic loading of surface roughness asperities as they pass through the contact. Representative measurements of the surfaces used in the experimental work were then evaluated using a numerical model which combines a transient line contact micro-elastohydrodynamic lubrication (micro-EHL) simulation with a calculation of elastic sub-surface stresses. This model generated time-history of stresses within a block of material as it passes through the contact, based on the instantaneous surface contact pressure and traction at each point in the computing mesh at each timestep. This stress time-history was then used within a shear-strain-based fatigue model to calculate the cumulative damage experienced by the surface due to the loading sequence experienced during the experiments. The proposed micro-EHL model results and the experimental study were shown to agree well in terms of predicting the number of loading cycles that are required for the initial micropitting to occur.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of Micropitting Initiation in Real Rough Surfaces in a Micro-elastohydrodynamic Lubrication Regime

et al. 2018

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“…The paper also presents a unified model for line contacts spanning the entire spectrum of mixed lubrication. Chang and Jeng 1 and Yu et al 3 extensively describe various approaches and contributions to mixed-lubrication modeling and justify the needs for additional developments to which the current paper is an integral part. The reader is referred to the two references for the literature review and background orientation of the subject matter.…”

Section: Introductionmentioning

confidence: 94%

“…The problem is now more tractable theoretically and a first-principle-based model may be developed for the contacts operating at this end of the mixed-lubrication spectrum. One such model for line contacts was recently developed in Yu et al 3…”

Section: Modeling Preliminariesmentioning

confidence: 99%

“…The model builds on the platform of Johnson et al 2 and incorporates into it a number of thermal, mechanical, and tribochemical ingredients of mixed lubrication at the asperity level. Subsequently, Yu et al 3 presented a model for line contacts operating in boundary and near-boundary lubrication. The model assumes surface asperities are squashed to form a single contact.…”

Section: Introductionmentioning

confidence: 99%

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A unified mixed-lubrication model of rolling-sliding line contacts from elastohydrodynamic lubrication to boundary lubrication

Chang

Jeng

2016

Proceedings of the Institution of Mechanical Engineers, Part J:

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This paper presents a unified mathematical model spanning the entire mixed lubrication for rolling-sliding line contacts. A load-sharing parameter is defined to divide the lubrication spectrum into three regions with increasing proportion of solid load sharing: light-mixed lubrication, significant-mixed lubrication and near-boundary lubrication. The main effort of the work is to develop a model for significant-mixed lubrication and integrate it with two previously developed governing-equation based models for light-mixed and near-boundary lubrication. A preliminary model is first developed by means of smooth, monotonically increasing interpolations of key contact variables obtained by the light-mixed and near-boundary lubrication models. The variables include surface temperature in the contact, friction coefficient, friction power intensity and proportion of solid contact area to the area of the line contact. The model is then refined by factoring in a potential transition of surface tribofilm breakdown which may take place in the second half of the region of significant-mixed lubrication. A basic parametric analysis is presented in the paper to show the sensibility of the model in analyzing the effects of operating conditions on contact stability. The model may be used to perform basic design and analysis calculations for line contacts with various degrees of mixed lubrication. It may also be implemented into a gear-meshing model to study the gear performance under various temperature and lubrication conditions.

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“…Unfortunately, they only get an average oil temperature in contact. Yu et al 21 calculated the average flash temperature of line contacts in boundary lubrication. In reality, because of the inhomogeneous distribution of temperature in contact, the distribution of oil temperature and viscosity are inhomogeneous and changing continuously.…”

Section: Introductionmentioning

confidence: 99%

A new asperity interaction model considering transient flash temperature and inhomogeneous distribution of oil viscosity

Zhang

Zhao

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part J:

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A momentary contact of asperities will generate transient flash temperature phenomena in boundary lubrication. According to the viscosity–temperature characteristics of lubricant, the inhomogeneous distribution of temperature during the process of asperity contact would cause the inhomogeneous distribution of oil viscosity. This paper proposes a coupled Eulerian–Lagrangian based approach to analyze the influence of inhomogeneous distribution of viscosity on the friction coefficient of an asperity junction. The asperity interaction in boundary lubrication with different sliding velocities and different degrees of overlap of the undeformed surfaces were taken into account. Simulation results showed that the friction coefficient is proportional to the overlap and inversely proportional to sliding velocity. The results also showed that the influence of inhomogeneous distribution of oil viscosity on friction coefficient in boundary lubrication is limited.

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A mathematical model for rolling/sliding line contacts in boundary and near boundary lubrication

Cited by 8 publications

References 24 publications

Experimental and Numerical Study of Micropitting Initiation in Real Rough Surfaces in a Micro-elastohydrodynamic Lubrication Regime

Experimental and Numerical Study of Micropitting Initiation in Real Rough Surfaces in a Micro-elastohydrodynamic Lubrication Regime

A unified mixed-lubrication model of rolling-sliding line contacts from elastohydrodynamic lubrication to boundary lubrication

A new asperity interaction model considering transient flash temperature and inhomogeneous distribution of oil viscosity

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