关键词: 弹塑性接触, Carreau流变模型, 非牛顿润滑, 滚滑线接触, 摩擦系数

Abstract: The friction characteristics of the line contact rough surface are of great significance for the lubrication design and lubrication state prediction of mechanical structures.To predict the friction behavior of the elastic-plastic line contact surface under mixed lubrication condition,the Kogut-Etsion (KE) model and the Carreau model were utilized to describe the dry contact and the non-Newtonian characteristics of the lubricant respectively.A mixed friction coefficient model for the rolling-sliding coexisting line contact surface was proposed based on the load-sharing concept in which the normal load was shared by the lubricant film and the asperity.The effects of normal load,surface roughness,lubricant inlet viscosity and the micro-contact model on friction coefficient were analyzed.The results showed that the film thickness was reduced by shear thinning behavior of the lubricant film greatly,which caused more asperity to asperity contacts,thereby increasing in the total friction coefficient.With the conditions of light load,small roughness and high inlet viscosity,it was easier to occur that the transition from mixed to hydrodynamic lubrication.In the boundary and mixed condition,the total friction coefficient and the asperity friction coefficient predicted based on KE model were smaller than the results of  model only considering the pure elastic deformation of the asperity,while for the hydrodynamic friction coefficient,the result was opposite.

Key words: elastic-plastic contact, Carreau rheological model, non-Newtonian lubricant, rolling-sliding coexisting line contact, friction coefficient