Validation of EHL Contact Predictions under Time Varying Load

Venner, Cornelis H.; Wijnant, Ysbrand H.

doi:10.1243/135065005x33865

Cited by 21 publications

(21 citation statements)

References 14 publications

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“…As observed by Venner and Wijnant, ''…when the conditions under which a contact operates become more extreme, e.g. when the film is smaller, it is even more important that time-dependent effects are taken into account [26].'' The TFL system is this extreme case and therefore understanding and characterizing its unique behavior may be critically important.…”

Section: Discussionmentioning

confidence: 99%

Compressibility of Thin Film Lubricants Characterized Using Atomistic Simulation

Martini

Vadakkepatt

2010

Tribol Lett

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Compressibility of thin lubricating films remains incompletely understood. Molecular dynamics simulations of a polymeric fluid confined in a nanoscale channel are used to investigate the effects of pressure and temperature on a thin film's response to compression. The observed trends are analyzed and compared to predictions of traditional, bulk fluid compressibility models. At ambient temperatures and pressures, molecular dynamics and bulk fluid models predict consistent trends for both the volume ratio and the bulk modulus. However, small deviations between the models suggest that molecular-scale confinement may, under some conditions, affect a fluid's compressibility such that it is not necessarily predictable using bulk fluid theories.

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Section: Discussionmentioning

confidence: 99%

Compressibility of Thin Film Lubricants Characterized Using Atomistic Simulation

Martini

Vadakkepatt

2010

Tribol Lett

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“…Figure 7 shows the graphs h x ð Þ, which are obtained from equations (16), (17) (curves 1, 2, 4, 6, 8, 10, 12), and graphs h x ð Þ, which are obtained from equation (28) (curves 1, 3,5,7,9,11,13). These results indicate that changing the convective derivative on the partial derivative does not influence film thickness initially.…”

Section: Resultsmentioning

confidence: 84%

“…A number of theoretical works are devoted to studies of how the loading affects the EHD-contact characteristics. [1][2][3] Jin et al 4 explored the transient processes in the EHD contact during fast loading or speed variations. Hooke 5,6 produced graphs that enable one to determine the smallest lubricating layer thickness in reciprocation motion.…”

Section: Introductionmentioning

confidence: 99%

Effects of lubricant viscoelasticity on film thickness in elastohydrodynamic line contacts during start-up

Usov

2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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By means of numerical simulation the elastohydrodynamic lubricating film formation during start-up of motion of a line contact from rest is studied. The transition from solid contact to lubricated contact is of importance in investigating the start-up process and its effects on bearing performance. The numerical results of and others, concerning point contact and Newtonian lubricant, are not in good agreement with the known experimental data. The numerical film thickness is significantly smaller than the experimental values and the experimental velocity at which lubricant travels through the conjunction does not equal the entrainment velocity of numerical results. In the current paper, a lubricant with viscoelastic properties is considered. The Maxwell model of a lubricant at pure rolling of elastic cylinders is used. Also, as well as in work of Usov (2008) the model assumes the division of the whole area of contact into three zones: the dry contact of surfaces, the transient zone and the zone in which the surfaces are separated by a liquid lubricant layer. The rigid body model is assumed for the lubricant in the transient zone. The effects of viscoelasticity and size of transient zone on film thickness and the velocity at which the lubricant moves through the contact are studied. It is shown that viscoelasticity raises film thickness in a start of the motion and lowers the velocity at which the lubricant moves through the contact. This velocity is lower than the entrainment velocity in the first half of the contact, as in the experimental results with point contact. In the second half of the contact, this velocity may be lower or higher than the entrainment velocity depending on the size of the transient zone. The film thickness may increase considerably at the start of motion when the size of the transient zone increases.

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“…6 analysed the film thickness fluctuations due to structural vibrations in elasto-hydrodynamic lubrication (EHL) contacts and highlighted the limitation of steady state analyses. Later, the authors 7 investigated the accuracy of the simulated EHL responses to load fluctuations by comparing some of their previous results 8 with the experimental evidence of Sakamoto et al. 9 Wang et al.…”

Section: Introductionmentioning

confidence: 99%

Modelling of damping in lubricated line contacts – Applications to spur gear dynamic simulations

Ankouni

Lubrecht

Velex

2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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The various damping mechanisms in elasto-hydrodynamic lubrication contacts are investigated with the objective of deriving damping models representative of the lubricant contributions which can readily be used in gear dynamic simulations. Several simplified models are proposed which make it possible to simulate the damping caused by tooth friction and lubricant squeezing by the teeth with and without momentary contact losses and impacts. A one-degree-of-freedom gear dynamic model is set up which combines these lubricant damping sources along with structural damping. A number of comparisons with benchmark experimental evidence are presented for a range of operating conditions and gear geometries which prove that the proposed approach is sound in the case of spur gears. It is shown that the damping associated with lubricant squeezing contributes for the most part when contact losses and shocks between the teeth occur at critical speeds. For permanent contact conditions, however, structural damping appears as the major contributor to the overall system damping.

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Validation of EHL Contact Predictions under Time Varying Load

Cited by 21 publications

References 14 publications

Compressibility of Thin Film Lubricants Characterized Using Atomistic Simulation

Compressibility of Thin Film Lubricants Characterized Using Atomistic Simulation

Effects of lubricant viscoelasticity on film thickness in elastohydrodynamic line contacts during start-up

Modelling of damping in lubricated line contacts – Applications to spur gear dynamic simulations

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