A model to predict scuffing failures of a ball-on-disk contact

The Effects of Microdimple Texture on the Friction and Thermal Behavior of a Point Contact

“…The micro-scale surface topography of rolling mechanical elements (bearings and gears for example) plays an important role in the frictional power loss [1][2][3][4], the surface wear [5,6], the rolling contact fatigue (micro and macro scale pitting) failure [7][8][9][10][11][12], and the surface temperature related scuffing failure [13][14][15]. In the heavily loaded contacts of gearing applications, the presence of the significant surface roughness profiles (tool marks) due to the finishing processes, such as shaving and grinding, introduces frequent asperity Contacts within the elastohydrodynamic lubrication (EHL) conjunction.…”

“…Owing to the asperity contacts, the lubrication film breaks down, where not only the surface tractions but also the surface temperature peak, dictating the friction [1][2][3], and the failures of fatigue [11] and scuffing [15]. To improve the rolling contact performances in these aspects, the surface polishing process that eliminates the local roughness peaks has been shown to be a successful method [1,[17][18][19][20][21].…”

“… Investigate the effects of micro-dimples on the friction and surface temperature performances of a lubricated point contact, which operates under the speed ranging from 0.5 to 10 m/s and the load ranging from 0.5 to 2.5GPa, using the thermal mixed EHL point contact model proposed by Li et al [15],  Employing a ball-on-disk contact, the micro-dimple arrays with different dimple center distances and dimple depths will be implemented on the ball surface to quantify the impacts of these two parameters on the friction coefficient and the maximum ball surface temperature.…”

“…For a non-conformal point contact of rough surfaces, the thin film hydrodynamic fluid flow within the EHL channel follows the transient two-dimensional (2D) Reynolds equation of [14][15][16] ( ) ( )…”

“…As the contact surfaces of body 1 and body 2 move at the surface tangential velocities of 1 u and 2 u , the lubricant is entrained into the contact zone at the rate of r u , which is usually referred as the rolling or entraining velocity, and is defined as Assuming an Eyring fluid, whose characteristic reference stress is 0  , these coefficients take the forms of [14,15] Because of the significant surface roughness irregularities of the mechanical elements such as gears, the full film lubrication condition where the contact surfaces are completely separated by the protective fluid film, is hardly achievable. When, for instance, the circumstance of insufficient rolling velocity and/or high lubricant temperature that reduces the lubricant viscosity and consequently the film thickness is encountered, frequent local asperity contacts take place within the contact zone.…”