Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

The characterization of a layered structure has been considered by many investigators. A variety of techniques has been introduced. Among these normal incidence longitudinal waves can be applied in the low frequency regime, and the transmitted and/or reflected signals can be used for the evaluation of a layered medium [1, 2]. In the technique discussed in Ref. [1], a reference signal has to be introduced in order to calibrate the evaluation. In recent work by the present authors, a self-compensating technique has been proposed to evaluate a layered structure, in that a ratio of transmission and reflection coefficients has been used [3]. Applications using a self-calibrating or self-compensating technique for the measurement of surface waves reflected or transmitted by a surface-breaking crack have been reported in Refs. [4, 5]. The major advantage of the technique is that the evaluation is independent of the characteristics of transmission and reception of ultrasound by the transducers, the attenuation in the couplant and the surface condition of the specimen. The technique is not only applicable for a contact configuration but an immersion configuration as well.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16B

Chapter

Chapter 7: New Inspection Procedures

Section

New Techniques

Pages

1815-1822

DOI

10.1007/978-1-4615-5947-4_237

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

A Self-Compensating Technique for the Characterization of a Layered Structure

Brunswick, ME

The characterization of a layered structure has been considered by many investigators. A variety of techniques has been introduced. Among these normal incidence longitudinal waves can be applied in the low frequency regime, and the transmitted and/or reflected signals can be used for the evaluation of a layered medium [1, 2]. In the technique discussed in Ref. [1], a reference signal has to be introduced in order to calibrate the evaluation. In recent work by the present authors, a self-compensating technique has been proposed to evaluate a layered structure, in that a ratio of transmission and reflection coefficients has been used [3]. Applications using a self-calibrating or self-compensating technique for the measurement of surface waves reflected or transmitted by a surface-breaking crack have been reported in Refs. [4, 5]. The major advantage of the technique is that the evaluation is independent of the characteristics of transmission and reception of ultrasound by the transducers, the attenuation in the couplant and the surface condition of the specimen. The technique is not only applicable for a contact configuration but an immersion configuration as well.