Lubricants reduce friction in machines and consequently save energy. They combat machine wear: adhesive wear and seizure, due to fatigue or contact corrosion. They thus help improve efficiency, extend the mechanism's lifespan, and increase its reliability.

Depending on the type of functions they are intended for, additives are used to enhance the lubricating performance of the fluids. However, this introduces a non-linear (non-Newtonian) behavior of the lubricants, capable of influencing all hydrodynamic parameters such as pressure, load, and friction.

This work focuses on the issues of overestimation or underestimation of operating characteristics caused by a linear (Newtonian) modeling of fluid behavior in lubricated contacts, particularly in the case of hydrodynamic bearings.