Influence of the contact model on the onset of sprag-slip

In systems with sliding-friction often strong self-excited vibrations do occur. One of the possible underlying mechanisms is the so-called sprag-slip instability. In the present work the onset of sprag-slip is investigated by a simple model in which an inclined elastic beam slides over a rigid belt moving with constant velocity. For a Coulomb friction law and a contact model with constant contact stiffness for a certain range of parameters the system loses its static solution corresponding to the steady sliding state. Simultaneously with this loss of existence of the static solution the qualitative properties of the system's flow field in phase space change, resembling a transition from stable to unstable behavior. To investigate the influence of contact models and related parameters on the details of this onset of sprag-slip also Hertz theory of elastic contact is applied. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)