Magnetic Pre-Loading for a Tonpilz-Type Acoustic Projector

Magnetic Pre-Loading for a Tonpilz-Type Acoustic Projector

Scott D. Moss, Ethan J. G. Ellul, Mason Paxevanos, George Jung, David Munk, Joel Smithard

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Abstract. This paper describes a new magnet-based method for applying a compressive pre-load to the piezoceramic elements of a Tonpilz-type acoustic projector, with the advantage of lower damping due to mechanical friction and a greater range of unhampered resonant motion since no plate spring is required. The Tonpilz-type acoustic projector can be applied to structural health monitoring studies involving air coupled ultrasound. Acoustic model predictions and the measured behaviour of a relaxor ferroelectric single crystal (RFSC) based prototype device, operating in air, are presented and show good correlation. With a 5 V drive, at 9420 Hz resonance, the prototype device generates a sound pressure level of 113 dB measured at an axial distance of 5 mm. The maximum peak tip displacement of the device’s head mass is predicted to be 0.7 µm at resonance. This is well within the 2 µm displacement produced by the 90 N magnetic pre-load, thus protecting the RFSC ceramic element from damaging tensile stress.

Magnetic Force, Tonpilz, Acoustic Projector, Relaxor Ferroelectric Single Crystal

Published online 2/20/2021, 9 pages
Copyright © 2021 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: Scott D. Moss, Ethan J. G. Ellul, Mason Paxevanos, George Jung, David Munk, Joel Smithard, Magnetic Pre-Loading for a Tonpilz-Type Acoustic Projector, Materials Research Proceedings, Vol. 18, pp 1-9, 2021


The article was published as article 1 of the book Structural Health Monitoring

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