Some Aspects Concerning the Behaviour of Friction Materials at Low and Very Low Sliding Speeds

The tribological aspects concerning the behaviour of friction materials in the range of low and very low sliding speeds (0.2 ? 200 mm/min) are essentially different of those in the high sliding speeds range. This paper aims to study the stick-slip phenomenon which occurs in the range of low and very low speeds. Typically, for the stick-slip phenomenon to occur, the static friction coefficient between the two contact surfaces of the friction materials must be larger than the kinetic friction coefficient. For disc brakes, the stick-slip phenomenon is mentioned in many specialized scientific papers. The phenomenon is manifested through self-induced vibrations. The experimental results were obtained on a dedicated testing machine where the parasite stick-slip motion is reduced through the use of bearings.