Elastohydrodynamic Film Thickness in Elliptical Contacts With Spinning and Rolling

Zou, Qian; Changhua, Huang; Wen, Shizhu

doi:10.1115/1.2834124

Cited by 21 publications

(6 citation statements)

References 13 publications

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“…Spin has been well studied for point (Li, et al, 2010) and elliptical (Dowson, et al, 1993;Zou, et al, 1999) bearing contacts. The spin will introduce additional off-axis flow forces in the direction of spin rotation within the inlet region; further disrupting the PAL mechanism.…”

Section: Implications For Hip Implant Lubricationmentioning

confidence: 99%

The effect of transient conditions on synovial fluid protein aggregation lubrication

Myant

Cann

2014

Journal of the Mechanical Behavior of Biomedical Materials

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Little is known about the prevailing lubrication mechanisms in artificial articular joints and the way in which these mechanisms determine implant performance. The authors propose that interfacial film formation is determined by rheological changes local to the contact and is driven by aggregation of synovial fluid proteins within the contact inlet region. A direct relationship between contact film thickness and size of the protein aggregation within the inlet region has been observed.In this paper the latest experimental observations of the protein aggregation mechanism are presented for conditions which more closely mimic joint kinematics and loading. Lubricant films were measured for a series of bovine calf serum solutions for CoCrMo femoral component sliding against a glass disc. An optical interferometric apparatus was employed to study the effects of transient motion on lubricant film formation. Central film thickness was measured as a function of time for a series of transient entrainment conditions; start-up motion, steady-state and non-steadystate uni-directional sliding, and bi-directional sliding. The size of the inlet aggregations was found to be dependent upon the type of transient condition. Thick protective protein films were observed to build up within the main contact region for all uni-directional tests. In contrast the inlet aggregation was not observed for bi-directional tests. Contact film thickness and wear was found to be directly proportional to the presence of the inlet protein phase. The inlet phase and contact films were found to be fragile when disrupted by surface scratches or subjected to reversal of the sliding direction.

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Section: Implications For Hip Implant Lubricationmentioning

confidence: 99%

The effect of transient conditions on synovial fluid protein aggregation lubrication

Myant

Cann

2014

Journal of the Mechanical Behavior of Biomedical Materials

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“…In the last one, rolling, sliding, and spin motions were imposed in elliptical contacts. More recently, Zou, et al (6) and Yang and Cui (7) also studied similar operating conditions. These papers focused on pressure and film thickness prediction and none of them considered the spin effect on friction.…”

mentioning

confidence: 88%

First Traction Results of High Spinning Large-Size Circular EHD Contacts from a New Test Rig: Tribogyr

Dormois

Fillot

Vergne

et al. 2009

Tribology Transactions

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This article presents a new test rig named Tribogyr and the first results obtained so far. This device allows EHL friction tests in rolling-sliding under high spinning conditions applied to large-size circular contacts. Spinning is imposed thanks to a unique design that includes a tilting facility of one of the two spindles. After a brief description of the test rig structure and of the specimen geometry, the sensor's implementation and the device capabilities are reported. The parameter used to quantify the spin in this study is then defined. It only takes into account the rotational speed normal to the contact surface and the contact radius. Then, the friction coefficient and the temperature measurements are presented. The data are at first plotted versus the classical slide-to-roll ratio and compared to numerical results obtained with and without spin. The spin parameter then is introduced to replace the slide-to-roll ratio as the varying parameter. This representation allows reporting all the results in the same figure, where the influence of the operating conditions like the entrainment speed, the tilting angle, and the slide-to-roll ratio on friction and on temperature is much more visible. It is discussed that the observed temperature difference increase is generated by an additional shearing introduced by spinning despite an observed reduction of friction.

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“…Proper lubrication is helpful to reduce friction and improves the service life. Among the early researches, elastohydrodynamic lubrication (EHL) studies had been carried out by Dowson et al (1991) and Zou et al (1999), whereas the above researches all neglected the thermal effect. Later, Ehret et al (2000), Yan et al (2014) and Shi et al (2016) have completed the EHL analysis with the thermal effect.…”

Section: Introductionmentioning

confidence: 99%

Coupling analysis of the fatigue life and the TEHL contact behavior of ball screw under the multidirectional load

Zhao

Lin

Song

et al. 2020

ILT

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Purpose This paper aims to provide thermal elastohydrodynamic lubrication (TEHL) contact model to study all balls’ lubrication performance of the ball screw when the multidirectional load is applied. Design/methodology/approach A new TEHL contact model combining the multidirectional load and the roughness surface texture is established to describe fatigue life of the ball screw. Meanwhile, the authors use the Reynolds equation to study the lubrication performance of the ball screw. Findings When the multidirectional load is applied, contact load, slide-roll ratio and entrainment velocity of all balls have a periodic shape. The TEHL performance values at the ball-screw contact points including contact stress, shear stress, minimum film thickness and temperature rise are higher than that at the ball-nut contact points. The TEHL performance values increase with the increase of root mean square (RMS) except for the film thickness. In addition, the radial load of the ball screw has a significant effect on the fatigue life. Originality/value The results of the studies demonstrate the new TEHL contact model that provides the instructive significance to analyze the fatigue life of the ball screw under the multidirectional load. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0097/

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Elastohydrodynamic Film Thickness in Elliptical Contacts With Spinning and Rolling

Cited by 21 publications

References 13 publications

The effect of transient conditions on synovial fluid protein aggregation lubrication

The effect of transient conditions on synovial fluid protein aggregation lubrication

First Traction Results of High Spinning Large-Size Circular EHD Contacts from a New Test Rig: Tribogyr

Coupling analysis of the fatigue life and the TEHL contact behavior of ball screw under the multidirectional load

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