Location

Snowbird, UT, USA

Start Date

1-1-1999 12:00 AM

Description

Lamb waves have been widely used in ultrasonic NDE to characterize material properties or assess material quality [1], Of the previous work on materials using phase-matched fluid-loaded coupling, most has been performed in water-coupled testing [2]. With the development of efficient non-contacting ultrasonic air-coupled transducers [3], it has become feasible to apply air-coupled ultrasonic methods to NDE. Because of the low signal noise ratio resulting from the large impedance mismatch between the air and the solid object, most work of air-coupled (AC) ultrasound is qualitative, with defects in plates and C-scan imaging being the principal objectives. As demonstrated by Safaeinili, et al. [4], however, it is possible to characterize elastic plates, both isotropic and anisotropic, by using AC ultrasound, despite the signal-to-noise ratio (SNR) penalty.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

18B

Chapter

Chapter 5: Engineered Materials

Section

Composites

Pages

1273-1280

DOI

10.1007/978-1-4615-4791-4_163

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Air-Coupled Ultrasonic Beam Transmission Applied to Material Characterization

Snowbird, UT, USA

Lamb waves have been widely used in ultrasonic NDE to characterize material properties or assess material quality [1], Of the previous work on materials using phase-matched fluid-loaded coupling, most has been performed in water-coupled testing [2]. With the development of efficient non-contacting ultrasonic air-coupled transducers [3], it has become feasible to apply air-coupled ultrasonic methods to NDE. Because of the low signal noise ratio resulting from the large impedance mismatch between the air and the solid object, most work of air-coupled (AC) ultrasound is qualitative, with defects in plates and C-scan imaging being the principal objectives. As demonstrated by Safaeinili, et al. [4], however, it is possible to characterize elastic plates, both isotropic and anisotropic, by using AC ultrasound, despite the signal-to-noise ratio (SNR) penalty.