Non-contact nonlinear acoustic damage localization in plates. Part 2: Localized resonance through dynamically trapped modes

Document type: Journal Articles
Article type: Original article
Peer reviewed: Yes
Author(s): Claes Hedberg, Kristian Haller
Title: Non-contact nonlinear acoustic damage localization in plates. Part 2: Localized resonance through dynamically trapped modes
Journal: Acta Acustica united with Acustica
Year: 2008
Volume: 94
Issue: 1
Pagination: 48-53
ISSN: 1610-1928
Publisher: S. Hirzel Verlag GmbH
ISI number: 000252983600007
Organization: Blekinge Institute of Technology
Department: School of Engineering - Dept. of Mechanical Engineering (Sektionen för teknik – avd. för maskinteknik)
School of Engineering S- 371 79 Karlskrona
+46 455 38 50 00
http://www.bth.se/ing/
Authors e-mail: claes.hedberg@bth.se, kristian.haller@bth.se
Language: English
Abstract: This work is the second part of three that presents new tools to be used for damage localization in plates by nonlinear acoustical methods. It introduces an important in-plane localization technique, which is based on the existence of resonant spatially localized wave fields. The wave from the transducer is acting as a dynamic influence on the plate surface, making the waves reflect in a non-ideal way. The non-ideal reflections make the modes underneath the transducer have different resonant frequencies than the modes beside the insonified area. They appear both for contact and non-contact sources. In the nonlinear damage localization application, the trapped mode wave field interacts with another signal at lower frequency. This results in sidebands around the high frequency whose amplitudes are related to the amount of damage underneath the transducer.
Subject: Physical Acoustics\General
Mechanical Engineering\Structural Mechanics
Keywords: Dynamically trapped modes, Nonlinear acoustics, Damage detection
Edit