TRIBOS: A performance evaluation tool for traction-transmitting partial ehd contacts

The details are given of a computer model for performing a state-of-the-art tribological assessment of the performance of a lubricated concentrated rolling/sliding/spinning/contact comprising general anisotropic rough surfaces. The name chosen for this program is TRIBOS. It computes: 1. The contact ellipse dimensions and area 2. The elastohydrodynamic (EHD) film thickness both at the plateau and at the constriction that forms at the rear of a lubricated concentrated contact under fully flooded (un-starved) and isothermal lubricant inlet conditions 3.The apportionment of the applied load between the asperities and the lubricant film 4.The magnitude and direction of the tractive force transmitted between the contacting bodies by the combined effects of (a) shearing of the fluid film and (b) coulomb friction between contacting asperities 5. The mean number of asperity contacts and the real contact area, i.e. the total contact area of the elastically deformed asperities 6. A film thickness correction factor accounting for lubricant starvation in the contact inlet 7. A film thickness correction factor accounting for a viscosity decrease of the inlet oil due to fluid heating 8. An index of surface fatigue behavior The program is a synthesis of computational tools from the current literature for the computation of fluid film thickness and traction, and a general asperity simulation model for the elastic contact of anisotropic rough surfaces. In the example given, it is used to perform a comparative evaluation of the performance of 18 combinations of 9 surface roughnesses and 2 lubricants in a traction drive contact.