EHL performance of the lubricant with sheer strength: Part I - Boundary slippage and film failure

This paper analytically investigates the isothermal line contact elastohydr odynamic lubrication of three lubricants with match different shear strengt hs under the nondimensional operating parameters of w = 2.15e-4 and U = 2.5 3e-10 applying the lubricant ideal viscoplastic rheological model. The boun dary slippage of the low-shear-strength lubricant occuring in the EHL inlet zone was found and results in a much thinner film compared to the classica l EHL theory prediction. The film boundary slippage and its growth with the slide/roll ratio variation of the low-shear\strength lubricant exhibit spe cial phenomena, which are much different from those of the high-shear-stren gth lubricant. The easy occurrence of film failure in concentrated contact in the case of high sliding speed, heavy lend, large slide/roll ratio, and low-shear-strength lubricant was concluded due to the severe friction heati ng on the surface conjunction and the lubricant thermal desorption on the l ubricant/surface boundary. The EHL film failure mechanism was further recog nized.