Numeric simulations in tribology - dry contact and solid lubrication

Understanding the causes and consequences of friction on the behavior of bodies in contact has been the day-to-day business of tribologists for many centuries. In fact, it's not just the bodies in contact that are concerned, but also the mechanism(s) that contain(s) them, and the interface that separates them.

This understanding is not simply a scientific curiosity, but the key to major industrial challenges. Controlling the lifespan of mechanisms (automotive and aeronautical brake discs, bearings, household appliances, etc.) and material shaping tools, safety (shunting problems in wheel-rail contact or current collection in pentograph/catenary contact, etc.), public health (wear on joint implants) and the environment (squeal reduction, improved lubricants, etc.) are all problems directly linked to the consequences of friction.

Because experimentation can sometimes find its limits in the dynamic analysis of such systems, especially under severe stress (high pressure and shear rate), numerical tools have emerged to fill the information gaps left by experimental approaches for both "dry contact" conditions (no lubricant added) and "lubricated contact" conditions (oil, grease, etc.). Today, numerical approaches are much more than a simple complementary tool, they are an integral part of understanding phenomena and are tending to become predictive tools.

Numerical approaches are available for both the dry and lubricated aspects mentioned above. In these few pages, we have chosen to focus solely on dry contact. The "lubricated contact" aspects, in the sense of fluid lubrication, will only be touched on briefly.