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

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.

Keywords
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

DOI: https://doi.org/10.21741/9781644901311-1

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

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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