A modified torsional Kolsky bar for investigating dynamic friction

This paper introduces an experiment to investigate dry sliding resistance o f frictional interfaces at normal pressures up to 100 MPa, slip speeds up t o 10 m/s and slip distances of approximately 10 mm. This new apparatus invo lves a novel modification of the conventional torsional Kolsky bar apparatu s, employed extensively in the past for investigating high strain rate beha vior of engineering materials. The new experimental configuration represent s a significant improvement over conventional tribology experiments because it uses elastic torsional waves with a superimposed static compressive for ce to control the interfacial traction. Moreover, the apparatus allows crit ical frictional parameters such as the interfacial sliding resistance, slip speeds and slip displacement to be interpreted on a microsecond time scale without the use of transducers at the frictional interface. The usefulness of the device is demonstrated by presenting results of high-speed friction on 6061-T6 Al/1018 steel and Carpenter Hampden tool steel/7075-T6 Al tribe pairs.