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Active Friction Control Using Ultrasonic Vibration

: Scherer, V.; Arnold, W.

Bhushan, B. ; National Science Foundation -NSF; United States, Air Force, Office of Scientific Research -AFOSR-; American Society of Mechanical Engineers -ASME-:
Tribology issues and opportunities in MEMS. Proceedings of the NSF/AFOSR/ASME Workshop
Dordrecht: Kluwer Academic Publishers, 1998
ISBN: 0-7923-5024-3
Workshop on Tribology Issues and Opportunities in MEMS <1997, Columbus/Ohio>
Fraunhofer IZFP ()
atomic force microscopy; elastohydrdynmic lubrication; friction force microscopy; Squeeze Film; ultrasound; vibration analysis

In this paper, the mechanism of reduction of friction by ultrasonic vibration has been studied. Experiments have been conducted by vibrating the specimen surfaces at ultrasonic frequencies. We found that vibration of the surfaces with amplitudes as low as a few nanometers evokes a super-lubricating effect when the frequency of vibration is high enough, here greater than 500 kHz. With a Pin-on-Flat (POF) test apparatus, a reduction of sliding (kinetic) friction was observed on surfaces vibrating laterally (inplane), vertically (out-of-plane) of ellipsoidally (both in-plane and out-of-plane components). Sliding a sharp tip of an Atomic Force Microscope (AFM) against a vibrating surface revealed near-zero friction. Whereas friction is reduced, we find that a dramatic increase in wear can occur when contact resonances are excited. Thus, contact resonance can be used for ultrasonic machining.