Rate- and state-dependent friction model for elastomeric seals

Seals are crucial for the functionality of pneumatic linear actuators. They separate chambers with different pressure levels. Little air leakage which leads to reduced volumetric efficiency is often accepted. More important is the role of friction which decreases the efficiency caused by tribological contacts between seals and counter surfaces. Furthermore, friction leads to reduced precision. Static friction models are state of the art within the designing of pneumatic systems including cylinder devices. These friction models are based on a description of the Stribeck curve. But they are not able to predict dynamic friction instabilities like stick-slip, increasing break-away force due to dwell-time and hysteretic friction phenomena. The paper shows a simulation approach based on a powerful rate- and state-dependent friction model. Loads on the tribological contact between seal and rod are realised by a structural mechanics method. The numerical results are compared with experimental investigations.