Thermo-Mechanical Investigation of a Rotational Friction Joint Under High-Frequency Excitation

High-frequency excitation is known to influence systems with friction such that undesired phenomena can be suppressed. In the present publication, a rotational friction joint under axial high-frequency excitation is investigated theoretically, and a corresponding experimental test rig is presented. The focus is on the thermo-mechanical coupling in the system, as friction-induced heat generation can lead to a higher contact pressure, which results in higher friction forces. A coupled model of a linear oscillator and a thermo-mechanical continuum gives insight into the interactions between friction, heat evolution, and vibrations. In the test rig, the necessary torque to supply a constant shaft rotation in a friction bearing is measured. A piezoelectric actuator excites the bearing to axial oscillations. Furthermore, the temperature of the shaft's friction contact is measured by a non-contact pyrometer. A relation between high-frequency excitation, friction torque, and heat evolution can be analyzed this way.