Paper 14: Partial Elastohydrodynamic Lubrication in Rolling Contact

Tallian, T. E.; McCool, John I.; Sibley, L. B.

doi:10.1243/pime_conf_1965_180_077_02

Cited by 15 publications

(8 citation statements)

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“…A number of previous works highlighted the influence of specific film thickness and surface roughness on life [2], [6][7][8][9][10][11][12][13][14]. Other authors showed that surface traction and its direction was significant [2][15] [16].…”

Section: Introductionmentioning

confidence: 99%

Propagation of surface initiated rolling contact fatigue cracks in bearing steel

Rycerz

Olver

Kadiric

2017

International Journal of Fatigue

131

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Surface initiated rolling contact fatigue, leading to a surface failure known as pitting, is a life limiting failure mode in many modern machine elements, particularly rolling element bearings. Most research on rolling contact fatigue considers total life to pitting. Instead, this work studies the growth of rolling contact fatigue cracks before they develop into surface pits in an attempt to better understand crack propagation mechanisms. A triple-contact disc machine was used to perform pitting experiments on bearing steel samples under closely controlled contact conditions in mixed lubrication regime. Crack growth across the specimen surface is monitored and crack propagation rates extracted. The morphology of the generated cracks is observed by preparing sections of cracked specimens at the end of the test. It was found that crack initiation occurred very early in total life, which was attributed to high asperity stresses due to mixed lubrication regime. Total life to pitting was dominated by crack propagation. Results provide direct evidence of two distinct stages of crack growth in rolling contact fatigue: stage 1, within which cracks grow at a slow and relatively steady rate, consumed most of the total life; and stage 2, reached at a critical crack length, within which the propagation rate rapidly increases. Contact pressure and crack size were shown to be the main parameters controlling the propagation rate. Results show that crack propagation under rolling contact fatigue follows similar trends to those known to occur in classical fatigue. A log-log plot of measured crack growth rates against the product of maximum contact pressure and the square root of crack length, a parameter describing the applied stress intensity, produces a straight line for stage 2propagation. This provides the first evidence that growth of hereby-identified stage 2 rolling contact fatigue cracks can be described by a Paris-type power law, where the rate of crack growth across the surface is proportional to the contact pressure raised to a power of approximately 7.5.

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Section: Introductionmentioning

confidence: 99%

Propagation of surface initiated rolling contact fatigue cracks in bearing steel

Rycerz

Olver

Kadiric

2017

International Journal of Fatigue

131

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“…5. The tests using the vacuum pump oil under nitrogen cover gas ended at A = 0.9 as noted before, but the wear rate is linearly related to A as Tallian et al [8] also found. Their data are reproduced in Fig.…”

Section: Wear Rate For Sliding Surfacesmentioning

confidence: 80%

“…The electrical contact resistance was measured in order to come to some conclusion on the real area of contact, as was done by Tallian and coworkers [ 8,121. However, usually electrical contact resistance is measured as if there are two states, metallic contact and "no" contact [ 121.…”

Section: Methodsmentioning

confidence: 99%

“…Few papers discuss the wear rate of surfaces in lubricated sliding, much less the mechanisms of wear in that regime. One of the more carefully developed models for the wear of lubricated sliding systems is the shared load wear model of Tallian et al [8]. In this model, part of the applied load across a sliding boundary is carried by the lubricant trapped between the surfaces, and part of the load is carried by asperities that stand higher than the thickness of the lubricant film.…”

Section: Lubricatedmentioning

confidence: 99%

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The shared-load wear model in lubricated sliding: Scuffing criteria and wear coefficients

Lee

Ludema

1990

Wear

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One model that is offered for predicting the wear of minimally lubricated sliding parts suggests that wear may be predicted directly from the mechanics of contact. In this model the lubricant is assumed to carry part of the applied load and asperities carry the remainder of the load by solid contact and adhesion with each other. Experiments show that the assumed metallic adhesion does not take place on the predicted scale in ordinary practice, and thus catastrophic wear does not necessarily take place. The reason is that protective chemical species form on the asperities to prevent high surface shear stress. These films form in all practical systems but are particularly effective when a proper running-in procedure is followed.

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“…Shotter [11] experimentally showed that the friction increases with the surface roughness. Tallian and his co-workers [12,13] proposed a ratio 0 between the elastohydrodynamic film thickness and the composite root mean square roughness to represent the mixed elastodydrodynamic regime ( < < 1 4 0 ). Poon [14] was concerned with the transition from the boundary to the mixed regime with a dimensionless parameter 1.0 2.0 and the transition from mixed to full EHL region with < 2.0 2.4 by using electrical-conductivity measurements.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the Stribeck curve under full-film Elastohydrodynamic Lubrication

Zhang

Biboulet

Venner

et al. 2020

Tribology International

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A B S T R A C TThe Stribeck curve shows the friction coefficient as a function of speed, viscosity and load. The viscosity times speed over load parameter can be interpreted as a film thickness. The film thickness over roughness parameter unifies friction curves in the isoviscous rigid regime. In this paper, the Stribeck curve is predicted numerically in the full-film Elastohydrodynamic Lubrication regime. It is shown that the lambda ratio is not the most appropriate parameter. A more elaborate parameter including the operating conditions and based on the Amplitude Reduction Theory [1] gives much better results. For a complex surface topography, the full numerical simulation is time-consuming. A rapid prediction method is proposed. Good agreement is found between the full numerical simulation and the prediction. (A.A. Lubrecht).Tribology International xxx (xxxx) xxx-xxx 0301-679X/

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Paper 14: Partial Elastohydrodynamic Lubrication in Rolling Contact

Cited by 15 publications

References 0 publications

Propagation of surface initiated rolling contact fatigue cracks in bearing steel

Propagation of surface initiated rolling contact fatigue cracks in bearing steel

The shared-load wear model in lubricated sliding: Scuffing criteria and wear coefficients

Prediction of the Stribeck curve under full-film Elastohydrodynamic Lubrication

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