Quantitative elastohydrodynamic film forming for a gear oil with complex shear-thinning
Perhaps the most thorough characterization of the elevated pressure properties of any commercial EHL lubricant is presented here for a gear oil. Compressibility, thermal conductivity, and low-shear viscosity were measured. Of particular interest is the shear dependence of viscosity, measured across...
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| Other Authors: | , , |
| Format: | article |
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2016
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| Online Access: | http://hdl.handle.net/10725/3003 http://dx.doi.org/10.1177/1350650115600185 https://journals.sagepub.com/doi/abs/10.1177/1350650115600185 |
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| Summary: | Perhaps the most thorough characterization of the elevated pressure properties of any commercial EHL lubricant is presented here for a gear oil. Compressibility, thermal conductivity, and low-shear viscosity were measured. Of particular interest is the shear dependence of viscosity, measured across four decades of stress, which shows two transitions each with a specific value of power-law exponent. An attempt to capture a suspected third transition at very high stress resulted in mechanical degradation of the liquid in the viscometer. Numerical simulations of a point contact between a steel ball and a glass disc showed good agreement over a range of slide-to-roll ratio for the measured central thickness. The agreement for the minimum thickness was excellent. A new result is that shear-thinning of a higher molecular weight component that occurs from 3 to 200 kPa had little effect on the film thickness and could therefore be neglected in a film thickness calculation. |
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