Oscillatory and steady shear viscosity: The Cox-Merz rule, superposition, and application to EHL friction

被引：34

作者：

Bair, Scott ^{[1
]}

Yamaguchi, Tsuyoshi ^{[2
]}

Brouwer, Ludwig ^{[3
]}

Schwarze, Hubert ^{[3
]}

Vergne, Philippe ^{[4
]}

Poll, Gerhard ^{[5
]}

机构：

[1] Georgia Inst Technol, Ctr High Pressure Rheol, George W Woodruff Sch Mech Engn, Atlanta, GA 30332 USA

[2] Nagoya Univ, Grad Sch Engn, Dept Mol Design & Engn, Nagoya, Aichi 4648603, Japan

[3] Tech Univ Clausthal, Inst Tribol & Energiewandlungsmaschinen, D-38678 Clausthal Zellerfeld, Germany

[4] Univ Lyon, INSA Lyon, CNRS, LaMCoS UMR5259, F-69621 Villeurbanne, France

[5] Leibniz Univ Hannover, Inst Maschinenkonstrukt & Tribol, D-30060 Hannover, Germany

来源：

TRIBOLOGY INTERNATIONAL | 2014年 / 79卷

基金：

美国国家科学基金会;

关键词：

Elastohydrodynamic lubrication; Shear thinning; Time-temperature-pressure superposition; Cox-Merz rule; LIQUIDS; TRACTION; RHEOLOGY; FLOW; LUBRICATION; PREDICTION;

D O I：

10.1016/j.triboint.2014.06.001

中图分类号：

TH [机械、仪表工业];

学科分类号：

0802 ;

摘要：

The new quantitative approach to elastohydrodynamic lubrication requires a description of the steady shear dependent viscosity for calculations of film thickness and friction. This property can be obtained from measurements in pressurized thin-film Couette viscometers. However, frequency dependent viscosity can be obtained from a torsionally vibrating quartz crystal viscometer at high pressure or a relatively simple ambient pressure measurement with a shear impedance spectrometer. Here it is Shown for squalane and for a cyclic hydrocarbon and for a diester that both the steady shear dependent viscosity and the frequency dependent viscosity obey time-temperature-pressure superposition with the simplest shifting rule over the range of conditions investigated. Flow curves shift along a constant steady stress path or a constant complex modulus path. The Cox-Merz rule has been confirmed only for squalane and then only near the transition. The EHL friction for squalane at low pressure may be predicted with fair accuracy from the frequency dependent viscosity measured at ambient pressure. It appears that the Cox-Merz rule only applies to low-molecular-weight liquids when the molecule is composed of a long chain. (C) 2014 Elsevier Ltd. All rights reserved.

引用

页码：126 / 131

页数：6

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