The excitation and detection of lamb waves with planar coil electromagnetic acoustic transducers

Paul D Wilcox; Michael J S Lowe; Peter Cawley

doi:10.1109/tuffc.2005.1563281

The excitation and detection of lamb waves with planar coil electromagnetic acoustic transducers

IEEE Trans Ultrason Ferroelectr Freq Control. 2005 Dec;52(12):2370-83. doi: 10.1109/tuffc.2005.1563281.

Authors

Paul D Wilcox¹, Michael J S Lowe, Peter Cawley

Affiliation

¹ Department of Mechanical Engineering, University of Bristol, Bristol, BS8 1TR, UK. [email protected]

PMID: 16463504
DOI: 10.1109/tuffc.2005.1563281

Abstract

Planar coil electromagnetic acoustic transducers (EMATs) are investigated for the excitation and detection of Lamb waves in nonferromagnetic metallic wave-guides. Such EMATs are attractive for certain applications due to their omni-directional sensitivity to wave modes with predominantly in-plane surface displacement, such as the So Lamb wave mode. A model is developed that enables the modal content of the radiated Lamb wave field from a transmitting EMAT to be calculated, and the output voltage from a receiving EMAT to be predicted when a Lamb wave mode is incident on it. The predictions from this model are compared with experimental data obtained from 12 different EMATs tested on a 5-mm thick aluminum plate, and good agreement is obtained. The model then is used to analyze the different effects that contribute to the overall Lamb wave modal sensitivity of an EMAT. The relationship between coil geometry and wavelength is examined.

Publication types

Comparative Study
Evaluation Study
Research Support, Non-U.S. Gov't

MeSH terms

Acoustics / instrumentation*
Computer Simulation
Computer-Aided Design*
Equipment Design
Equipment Failure Analysis
Magnetics / instrumentation*
Models, Theoretical*
Reproducibility of Results
Sensitivity and Specificity
Transducers*
Ultrasonography / instrumentation*
Ultrasonography / methods