Abstract
This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion, in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an elastic semi-infinite heterogeneous solid with inhomogeneous inclusions. The impact–rebound process and the microscopic response of the subsurface inhomogeneous inclusions are investigated. The inclusions are homogenized according to Eshelby’s equivalent inclusion method. The Elrod algorithm is adopted to determine the lubrication starvation based on the solutions of pressure and film thickness, while the lubricant velocity and shear rate of the non-Newtonian lubricant are derived by using the separation flow method. The dynamic response of the cases subjected to constant impact mass, momentum, and energy is discussed to reveal the influence of the initial drop height on the impact–rebound process. The results imply that the inclusion disturbs the subsurface stress field and affects the dynamic response of the contact system when the surface pressure is high. The impact energy is the decisive factor for the stress peak, maximum hydrodynamic force, and restitution coefficient, while the dynamic response during the early approaching process is controlled by the drop height.
Highlights
Impact motion is involved in many manufacturing processes, such as shot-peening and ball-forming, causing dynamic loads on the machine transmission components
The present study develops a numerical model for starved thermal-elastohydrodynamic lubrication (EHL) of inhomogeneous material in impact motion
The material inhomogeneity is involved in the EHL problem in impact motion by means of Eshelby’s equivalent inclusion method
Summary
In the early numerical studies of EHL problems, the meniscus inlet boundary position was introduced as an known parameter to indicate the starvation conditions and predict the inlet oil layer thickness [11]. A generalized Reynolds equation was derived by Yang and Wen [13] based on the equivalent viscosity that coupled the non-Newtonian effects and thermal effects By applying such a method, non-Newtonian lubricants with different rheological properties were studied [14, 15]. The present study develops a numerical model for starved thermal-EHL of inhomogeneous material in impact motion. The EIM, Elrod algorithm, and separation flow method are adopted sequentially to deal with the effects of the inhomogeneous inclusions, lubrication starvation, and non-Newtonian properties. The dynamic response of the cases subjected to constant impact mass, momentum, and energy is discussed to reveal the influence of the initial drop height on the impact–rebound process
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