TY - GEN

T1 - Reduction of friction using piezoelectrically excited ultrasonic vibrations

AU - Littmann, W.

AU - Storck, H.

AU - Wallaschek, J.

N1 - Conference code: 8

PY - 2001/7/2

Y1 - 2001/7/2

N2 - Piezoelectric materials are an important class of smart materials for the generation of mechanical ultrasonic vibrations. In industrial applications (for example ultrasonic cutting) the frictional contact of the vibrating tool with the workpiece is of special importance. A common observation at the contact zone is that frictional forces can be significantly reduced by superposition of ultrasonic vibrations. In this report we present a theoretical explanation for the reduction of friction. A basic system, consisting of a longitudinal ultrasonic vibrator sliding on a plane, is investigated. It is shown that a modification of Coulomb's friction law can be applied to this kind of vibrating friction contact. The macroscopically observed friction-force with ultrasonic vibration depends on the sliding velocity and the velocity of vibration: For sliding velocities higher than the vibration-amplitude the frictional force is not changed by vibration. But for small sliding velocities the friction-coefficient is significantly reduced and almost approaches zero for very slow sliding-velocity. The theoretical results were confirmed systematically by experimental investigations done on a specially designed test-rig. Energy considerations are used to calculate the ultrasonic energy which is required to achieve a prescribed reduction of the frictional forces. The model is also used for sensing the vibration-amplitude as well as the sliding-velocity without an additional sensor.

AB - Piezoelectric materials are an important class of smart materials for the generation of mechanical ultrasonic vibrations. In industrial applications (for example ultrasonic cutting) the frictional contact of the vibrating tool with the workpiece is of special importance. A common observation at the contact zone is that frictional forces can be significantly reduced by superposition of ultrasonic vibrations. In this report we present a theoretical explanation for the reduction of friction. A basic system, consisting of a longitudinal ultrasonic vibrator sliding on a plane, is investigated. It is shown that a modification of Coulomb's friction law can be applied to this kind of vibrating friction contact. The macroscopically observed friction-force with ultrasonic vibration depends on the sliding velocity and the velocity of vibration: For sliding velocities higher than the vibration-amplitude the frictional force is not changed by vibration. But for small sliding velocities the friction-coefficient is significantly reduced and almost approaches zero for very slow sliding-velocity. The theoretical results were confirmed systematically by experimental investigations done on a specially designed test-rig. Energy considerations are used to calculate the ultrasonic energy which is required to achieve a prescribed reduction of the frictional forces. The model is also used for sensing the vibration-amplitude as well as the sliding-velocity without an additional sensor.

KW - Experimental

KW - Friction

KW - Modeling

KW - Piezoelectric

KW - Ultrasonic

UR - http://www.scopus.com/inward/record.url?scp=0034846002&partnerID=8YFLogxK

U2 - 10.1117/12.432714

DO - 10.1117/12.432714

M3 - Conference contribution

AN - SCOPUS:0034846002

VL - 4331

T3 - Proceedings of SPIE-The International Society for Optical Engineering

SP - 302

EP - 311

BT - Smart Structures and Materials 2001: Damping and Isolation

T2 - SPIE'S 8TH ANNUAL INTERNATIONAL SYMPOSIUM ON SMART STRUCTURES AND MATERIALS

Y2 - 4 March 2001 through 8 March 2001

ER -