کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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615782 | 881460 | 2010 | 9 صفحه PDF | دانلود رایگان |
The traction behaviour of various lubricants is investigated in elastohydrodynamic regime using a tribometre that simultaneously allows the contact visualization and the friction measurement under controlled contact kinematics. First, the film formation capability is determined: although the base oil and the polymer, via their viscosity, govern the film thickness in EHL regime, the additives control the existence of a boundary film at low entrainment speed. Second, the relative role of the additives and of the base oil on the frictional behaviour is studied for various experimental conditions: this clearly demonstrates that the piezo-viscous response of the lubricant controls the Newtonian/non-Newtonian transition and the friction level. The role of thermal effects is discussed. A strong influence of the entrainment speed, over the frictional response is unexpectedly observed, even in full film regime. A rheological model based on Ree–Eyring theory supposing a heterogeneous flow due to adsorbed surface layers, is proposed to discuss the organization of the molecules within the contact and its effect on the frictional response of the contact.
Journal: Tribology International - Volume 43, Issue 9, September 2010, Pages 1674–1682