Stabilization of sliding motion by partial stiction

Rotating friction disks are utilized in many drivetrain components such as dry clutches and their actuator systems. Even the simplest pin-on-disk or disk-on-disk mechanical systems with Coulomb friction reveal a rich dynamical behavior with different types of motions. Examining the radial dynamics of minimal friction disk models, it is a prevalent assumption to have pure sliding frictional contacts. Governed by the systems' design parameters and initial conditions, stable large amplitude motions at higher rotation speeds are possible. Using a Coulomb friction model with sticking and sliding instead, gives similar motions with alternating phases of sticking and sliding. However, the amplitude can be decreased significantly by these intermittent phases of stick and slip. It is suggested to exploit such motions with partial stiction in order to reduce amplitudes and thus stabilize the systems. Similar effects can be observed in 3D-multibody simulations and measurements of double clutch actuator systems. However, for these systems analytical treatment is not feasible any more due to the number of involved degrees of freedom. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)