Modelling of Dry Friction

Abstract

Dry friction plays an important role in the dynamic behaviour of mechanical systems. Mechanical systems can come to rest in a finite time due to the presence of dry friction. Moreover, dry friction is also responsible for stick-slip vibrations, which occur for instance in brakes, wheel-rail contact and bowed instruments such as violins. We briefly discuss the basic tribological phenomena related to dry friction in Section 4.1. Modelling of dry friction is far from trivial due to the intrinsically different nature of the sticking phenomenon and the sliding process of bodies in contact. Commonly used friction models are discussed in Section 4.2. Some friction models can be described by inclusions and form together with the equation of motion a differential inclusion, for which a well-defined solution concept exists (see Chapter 3). Dry friction models of this type, which lead to differential inclusions, will be used in Chapter 5 to set up a mathematical formulation for mechanical multibody systems with dry friction.