Instrumentación

High signal–to–noise ratio wedges for oblique incidence in ultrasonic testing

M. Ley–Koo and S. Salazar–Cruz

Instituto de Investigaciones Eléctricas, Avenida Reforma 113, Cuernavaca, Mor. 62490 MEXICO.

Recibido el 16 de marzo de 2006
Aceptado el 17 de abril de 2006

Abstract

It is experimentally shown that ultrasonic transmission through a column of couplant, with a thin film, at the end, produces greater amplitudes than through a piece of acrylic with the same length. This suggests the use of a wedge that could yield a greater signal–to–noise ratio than that of commercial wedges involved in oblique incidence ultrasonic inspection. The suggestion has been pursued, and the effects: on a weld are presented.

Keywords: Oblique incidence; wedges; ultrasonics; transmission; reflection.

Resumen

Se muestra experimentalmente que la transmisión de ultrasonido a través de una columna de acoplante, rematada con una película delgada, conduce a una amplitud mayor que aquella a través de una pieza de acrílico de la misma longitud. Esto sugiere la elaboración de una zapata que permita tener una razón señal–ruido mayor que aquella que proporcionan las zapatas comerciales utilizadas en la inspección con ultrasonido a incidencia oblicua. Siguiendo esta sugerencia se ha elaborado una zapata y se muestran los resultados de su uso en una placa soldada.

Descriptores: Incidencia oblicua; zapatas; ultrasonido; transmisión reflexión.

PACS: 81.70.Cv; 74.25.Ld

DESCARGAR ARTÍCULO EN FORMATO PDF

Acknowledgments

One of the authors (M. L–K) wishes to acknowledge the partial financial support of the Sistema Nacional de Investigadores as well as very useful comments by L. Medina–Gomez of the IIMAS–UNAM.

Referencias

1. B.A. Auld, Acoustic fields and waves in solids, Vol. II and references contained therein, John Wiley and Sons, Inc. (1973).        [ Links ]

2. A.B. Bhatia, Ultrasonic absorption: An introduction to the theory of sound absorption and dispersion in gases, liquids and solids and references contained therein, Oxford University Press, (1967).        [ Links ]

3. M.C. Bhardwaj, High transduction piezoelectric transducers and introduction of non–contact analysis, e–J. of Nondestructive Testing, Vol. 5, No. 1 (2000).        [ Links ]

4. M.C. Bhardwaj, Non–contact air coupled ultrasonic analysis: Introduction to transducers, analytical systems, and applications, e–J. of Nondestructive Testing, Vol. 6, No. 4 (2001).        [ Links ]

5. J. Buckley, Air–coupled ultrasound– A millenial review, 15 World Conference on NDT, Rome (2000).        [ Links ]

6. L. Lynnworth, Ultrasonic measurements for process control and references contained therein, Academic Press (1989).        [ Links ]

7. L. W. Schmerr, Fundamentals of Ultrasonic Nondestructive Evaluation, Plenum Press (1998)        [ Links ]

8. L.M. Brekhovskikh and O.A. Godin, Acoustics of layered media I, Springer Series on Wave Phenomena, Vol. 5, Springer (1998)        [ Links ]