Basic Study of Grease Rheology and Correlation with Grease Properties

Suetsugu, Yoshiyuki; Sekiguchi, Hiroki; Nakanishi, Yusuke; Fujinami, Yukitoshi; Ohno, Takuya

doi:10.2474/trol.8.83

Cited by 10 publications

(4 citation statements)

References 1 publication

(1 reference statement)

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“…Experimentally, higher values of the linear viscoelastic functions have also been found in commercial [40] and model [44] lithium greases with higher fibres concentration. Rheology measurements done on polystyrene [45] showed similar results. They call the low-frequency regime in which the moduli increase with increasing frequency the "flow (melt) region" where the molecules reptate through entanglements and relax.…”

Section: Oscillating Shearsupporting

confidence: 64%

A Coarse Grained Molecular Dynamics Model for the Simulation of Lubricating Greases

Benois,

Echeverri Restrepo,

De Laurentis

et al. 2024

Tribol Lett

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The rheological properties of lubricating greases are determined by the viscosity of the base oil, the interaction between base oil and thickener, and the interaction between thickener particles. The contribution of the oil–thickener interactions to the viscosity is well known, but the contribution of the thickener–thickener interactions has not yet been studied by employing theoretical or computational frameworks. In this paper, we use coarse-grained molecular dynamics to simulate a fibrous microstructure, and we show that the experimentally observed viscoelastic/plastic behaviour can be well reproduced. A parametric study shows that the apparent viscosity increases with increasing fibre length, fibre stiffness and thickener concentration. This is as expected, showing that this modelling approach is useful to study effects on grease rheology that are not accessible experimentally, such as impact of fibre entanglement or agglomeration.

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Section: Oscillating Shearsupporting

confidence: 64%

A Coarse Grained Molecular Dynamics Model for the Simulation of Lubricating Greases

Benois,

Echeverri Restrepo,

De Laurentis

et al. 2024

Tribol Lett

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“…Greases are classified according to the thickener agent that determines the gel-like characteristics. The thickener's type and composition, as well as the base oil's type and viscosity, temperature profile, mixing conditions and subsequent process conditions, according to Suetsugu et al [2], are the "manufacturing parameters" that varies the properties of grease. Investigations concerning the grease properties have been reported by many researchers, comprising the physiochemical or tribological properties.…”

Section: Introductionmentioning

confidence: 99%

Tribological and Physiochemical Properties of Greases for Rail Lubrication

2019

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Rail lubrication is vital in determines the friction, wear and noise level in the wheel and rail contacts. In general, the primary function of a rail curve grease is to minimize friction between the contact as well as to protect side wear of rails on a curved track. In this study, three commercially applied railway greases were identified and the wear and friction behavior, as well as the load-carrying ability, were investigated. Before that, the grease's physiochemical properties in terms of the consistency and drop point, as well as the element content, were also examined. The tribological investigation of the greases was also carried out using four-ball wear tester. In this test, the wear preventive (WP) and extreme pressure (EP) properties of the grease were measured under sliding actions between the balls, and the wear surface analysis was also carried out. The tests results explained that the rail curve greases are very soft in texture yet have stable structure over a high-temperature range. The greases also presenting low friction coefficient; ranges between 0.070 to 0.090, and acceptable wear scar diameter indicating the good anti-friction and anti-wear properties. High load-carrying ability up to 400 kg is also the significant properties for a rail curve grease to perform as the desired functions.

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“…The intermolecular binding energy of the thickener system is closely related to the dropping point for several stearates and the corresponding greases (Suetsugu et al , 2013). When the intermolecular binding energy was high, the melting point of the stearate and the dropping point of the corresponding grease were high.…”

Section: Resultsmentioning

confidence: 99%

Comparative analysis of stearates as grease lubricant thickeners

Yao

Wang²,

Yang³

et al. 2019

ILT

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Purpose This paper aims to investigate the influence of stearate types on the thickening ability, dropping point and fiber structure of greases. Design/methodology/approach Several greases were prepared from polyolefins and various stearates. The melting point of the stearates and the dropping point of the resultant greases were measured, and the intermolecular binding energies of the thickener and the radial distribution function of the metal–oxygen in the thickener were determined with the aid of molecular simulation. The microstructures of the greases were also analyzed via scanning electron microscopy. Findings A higher stearate binding energy was found to correlate to a higher dropping point of the resultant greases. The thickening ability of the stearate is related to the group and period of the constituent metal ion. Within a group, greater atomic numbers of the metal were correlated to lower thickening ability. In a period, as the atomic number of the metal increased, the thickening ability was enhanced. The radial distribution functions of metal and oxygen can explain the aggregation of the stearate thickeners in the grease. Originality/value This work compared the thickening capacity of several stearates. Guidelines for preparing stearates to tailor the resultant grease are presented.

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Basic Study of Grease Rheology and Correlation with Grease Properties

Cited by 10 publications

References 1 publication

A Coarse Grained Molecular Dynamics Model for the Simulation of Lubricating Greases

A Coarse Grained Molecular Dynamics Model for the Simulation of Lubricating Greases

Tribological and Physiochemical Properties of Greases for Rail Lubrication

Comparative analysis of stearates as grease lubricant thickeners

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