Thin-Film Rheology and Tribology of Magnetorheological Fluids in Isoviscous-EHL Contacts

Bombard, Antônio J. F.; Vicente, J. De

doi:10.1007/s11249-012-9971-2

Cited by 41 publications

(18 citation statements)

References 45 publications

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“…It is characterized by concentrated forces, high contact pressures (1-3 GPa), thin lubricant films (1-2000 nm), and short durations. Due to the high pressure and the limited contact area, elastic deformation of the surfaces will occur and it is not negligible, and the pressure dependence of viscosity plays a crucial role in EHL simulation because the viscosity at the inlet has crucial influence on film formation [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

2013

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This paper presents the application of an improved Yasutomi correlation for lubricant viscosity at high pressure in a Newtonian elastohydrodynamic line contact simulation. According to recent experimental studies using high pressure viscometers, the Yasutomi pressure-viscosity relationship derived from the free-volume model closely represents the real lubricant piezoviscous behavior for the high pressure typically encountered in elastohydrodynamic applications. However, the original Yasutomi correlation suffers from the appearance of a zero in the function describing the pressure dependence of the relative free volume thermal expansivity. In order to overcome this drawback, a new formulation of the Yasutomi relation was recently developed by Bair et al. This new function removes these concerns and provides improved precision without the need for an equation of state. Numerical simulations have been performed using the improved Yasutomi model to predict the lubricant pressure-viscosity, the pressure distribution, and the film thickness behavior in a Newtonian EHL simulation of a squalane-lubricated line contact. This work also shows that this model yields a higher viscosity at the low-pressure area, which results in a larger central film thickness compared with the previous piezoviscous relations.

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Section: Introductionmentioning

confidence: 99%

Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

2013

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“…The understanding of the tribological behaviour of these fluids is far to be complete in spite of its importance [4][5][6][7][8][9]. In many applications, dispersed iron microparticles have a typical size of the same order of magnitude as the gap thickness.…”

Section: Introductionmentioning

confidence: 99%

Boundary lubrication of magnetorheological fluids in PTFE/steel point contacts

Bombard

Vicente

2012

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“…Comparing the friction coefficients for each of the suspensions, we can note that the friction coefficient changes drastically from pure glycerol/water mixture to MR fluids (see Figure 3A). The classical Stribeck curve is observed for the carrier (without particles); boundary regime at small speeds, mixed regime at intermediate speeds and full film isoviscous-elastohydrodynamic lubrication regime for large speeds (Stribeck, 1902;Bombard and de Vicente, 2012;Wäsche and Woydt, 2014). In MR fluids, particles with larger diameters (M2 and M3) present larger friction coefficients, although the particle concentration is kept constant through the experiments (1 vol%).…”

Section: Friction Experiments and Stribeck Curvementioning

confidence: 99%

Tribological Behavior of Glycerol/Water-Based Magnetorheological Fluids in PMMA Point Contacts

2019

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Comprehension of the tribological behavior of magnetorheological fluids is crucial for many applications, in particular for those related with high quality surface finishing. In this contribution, we describe a thorough experimental investigation on the tribological properties of magnetorheological (MR) fluids in poly(methyl methacrylate) (PMMA) point contacts. First, magnetic iron oxide particles with diameters of ∼0.4, 1,3, and 2.0 µm were prepared using wet chemistry procedures. Then, MR fluids were formulated by dispersion of the magnetic particles in glycerol/water mixtures. The tribological experiments were run in a PMMA ball-on-three plates tribometer and Stribeck regions were identified for a wide range of sliding speeds. The wear tracks were also visualized in a confocal microscope to correlate them with friction coefficient data. The results show the effect of both particle size and applied magnetic field in the friction coefficient and wear scar volume, suggesting a slight decrease on the wear process when the magnetic field is present.

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Thin-Film Rheology and Tribology of Magnetorheological Fluids in Isoviscous-EHL Contacts

Cited by 41 publications

References 45 publications

Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

Effect of an Improved Yasutomi Pressure-Viscosity Relationship on the Elastohydrodynamic Line Contact Problem

Boundary lubrication of magnetorheological fluids in PTFE/steel point contacts

Tribological Behavior of Glycerol/Water-Based Magnetorheological Fluids in PMMA Point Contacts

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