Analytical Formula for the Ratio of Central to Minimum Film Thickness in a Circular EHL Contact

Šperka, Petr; Křupka, Ivan; Hartl, Martin

doi:10.3390/lubricants6030080

Cited by 12 publications

(17 citation statements)

References 22 publications

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“…Otherwise, the curves are limited to the boundaries of the domains over which the models were based. On the other hand, Table 2 summarizes & Khonsari [18]), the approaches of Chevalier [12], Sperka et al [33] and this work (plotted with dotted lines). [18]), the numerical approaches of Chevalier [12], Sperka et al [33] and this work.…”

Section: Comparisons With Previous Modelsmentioning

confidence: 75%

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A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

Habchi

Vergne

2021

Tribol Lett

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The current work presents a quantitative approach for the prediction of minimum film thickness in elastohydrodynamic lubricated (EHL) circular contacts. In contrast to central film thickness, minimum film thickness can be hard to accurately measure, and it is usually poorly estimated by classical analytical film thickness formulae. For this, an advanced finite-element-based numerical model is used to quantify variations of the central-to-minimum film thickness ratio with operating conditions, under isothermal Newtonian pure-rolling conditions. An ensuing analytical expression is then derived and compared to classical film thickness formulae and to more recent similar expressions. The comparisons confirmed the inability of the former to predict the minimum film thickness, and the limitations of the latter, which tend to overestimate the ratio of central-to-minimum film thickness.The proposed approach is validated against numerical results as well as experimental data from the literature, revealing an excellent agreement with both. This framework can be used to predict minimum film thickness in circular elastohydrodynamic contacts from knowledge of central film thickness, which can be either accurately measured or rather well estimated using classical film thickness formulae.

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Section: Comparisons With Previous Modelsmentioning

confidence: 75%

“…The central and minimum film thickness expressions are reported in Appendix B, together with the original Chevalier and Sperka et al (for = 20.6 −1 ) tables. Below are reported theexpressions of the ℎ /ℎ ratio that can be deduced from the three analytical models, the formula proposed by Sperka et al[33] is given in Appendix B:…”

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confidence: 99%

A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

Habchi

Vergne

2021

Tribol Lett

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“…-Chevalier [12] who was probably the first to tabulate the ℎ 𝑐 /ℎ 𝑚 ratio over wide ranges of 𝑀 and expressions of the ℎ 𝑐 /ℎ 𝑚 ratio that can be deduced from the three analytical models, the formula proposed by Sperka et al [33] is given in Appendix B:…”

Section: Previous Work and Expressionsmentioning

confidence: 99%

A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

Habchi

Vergne

2021

Preprint

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The current work presents a quantitative approach for the prediction of minimum film thickness in elastohydrodynamic lubricated (EHL) circular contacts. In contrast to central film thickness, minimum film thickness can be hard to accurately measure, and it is usually poorly estimated by classical analytical film thickness formulae. For this, an advanced finite-element-based numerical model is used to quantify variations of the central-to-minimum film thickness ratio with operating conditions, under isothermal Newtonian pure-rolling conditions. An ensuing analytical expression is then derived and compared to classical film thickness formulae and to more recent similar expressions. The comparisons confirmed the inability of the former to predict the minimum film thickness, and the limitations of the latter, which tend to overestimate the ratio of central-to-minimum film thickness. The proposed approach is validated against numerical results as well as experimental data from the literature, revealing an excellent agreement with both. This framework can be used to predict minimum film thickness in circular elastohydrodynamic contacts from knowledge of central film thickness, which can be either accurately measured or rather well estimated using classical film thickness formulae.

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“…with Most of these approaches were developed based upon numerical data and give an almost constant ratio of central and minimum film thickness. However, this ratio may vary between 1 and 3 depending on M and L. Therefore, Sperka et al [38] derived from experimental data an equation to predict this relation dependent on the pressure-viscosity coefficient αp: Central lubricant gap H c versus load parameter M at different viscosity parameters L using Equation (47) as well as the validity region of Hamrock-Dowson [34] and Nijenbanning et al [36], following [37].…”

Section: Point-and Elliptical Contacts (3d)mentioning

confidence: 99%

“…Most of these approaches were developed based upon numerical data and give an almost constant ratio of central and minimum film thickness. However, this ratio may vary between 1 and 3 depending on M and L. Therefore, Sperka et al [38] derived from experimental data an equation to predict this relation dependent on the pressure-viscosity coefficient α p :…”

Section: Point-and Elliptical Contacts (3d)mentioning

confidence: 99%

Non-Dimensional Groups, Film Thickness Equations and Correction Factors for Elastohydrodynamic Lubrication: A Review

et al. 2020

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Apart from complex numerical models to predict the tribological behavior of elastohydrodynamically lubricated contacts, non-dimensional similarity groups and analytically solvable proximity equations can be used to estimate integral fluid film parameters. Based upon the pioneering work presented by Dowson and Higginson as well as Blok and Moes, these approaches have been continuously improved over the years by modifications or correction factors to capture different contact geometries (line-, point- or elliptical contacts) as well as to include fluid compression, thermal, non-Newtonian, starvation or roughness effects. Consequently, this review article aims at systematically reviewing these modifications/corrections and discussing their applicability as well as limitations before presenting some recommendations for future research activities.

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Analytical Formula for the Ratio of Central to Minimum Film Thickness in a Circular EHL Contact

Cited by 12 publications

References 22 publications

A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

Non-Dimensional Groups, Film Thickness Equations and Correction Factors for Elastohydrodynamic Lubrication: A Review

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