Location

Snowmass Village, CO

Start Date

1-1-1995 12:00 AM

Description

Characterizing the wave field produced by an ultrasonic transducer is one important part of developing a complete measurement model of an ultrasonic NDE system. Within the paraxial approximation [1], this wave field can be expressed as a quasi plane wave field modified by a diffraction correction term to account for the 3-D effects of having a finite beam generated by the transducer. Previously, diffraction corrections have been obtained analytically in some simple cases [1] and numerically, using a Gauss-Hermite expansion [2]. Here, we will show that the radiation of both planar and spherically focused probes through a planar interface can be treated in a unified manner using angular plane wave spectrum integrals and the method of stationary phase. In the paraxial approximation, this unified approach will also be shown to produce diffraction corrections in the form of boundary diffraction waves [3]. These boundary diffraction wave diffraction corrections are in terms of at most 1-D integrations on the edge of the transducer, so that they can be easily evaluated numerically.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

14A

Chapter

Chapter 4: Transducers, Sensors, and Process Control

Section

Ultrasonic Transducer Fields and Ray Tracing

Pages

1061-1066

DOI

10.1007/978-1-4615-1987-4_134

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Modeling the Radiation of Focused and Unfocused Ultrasonic Transducers Through Planar Interfaces

Snowmass Village, CO

Characterizing the wave field produced by an ultrasonic transducer is one important part of developing a complete measurement model of an ultrasonic NDE system. Within the paraxial approximation [1], this wave field can be expressed as a quasi plane wave field modified by a diffraction correction term to account for the 3-D effects of having a finite beam generated by the transducer. Previously, diffraction corrections have been obtained analytically in some simple cases [1] and numerically, using a Gauss-Hermite expansion [2]. Here, we will show that the radiation of both planar and spherically focused probes through a planar interface can be treated in a unified manner using angular plane wave spectrum integrals and the method of stationary phase. In the paraxial approximation, this unified approach will also be shown to produce diffraction corrections in the form of boundary diffraction waves [3]. These boundary diffraction wave diffraction corrections are in terms of at most 1-D integrations on the edge of the transducer, so that they can be easily evaluated numerically.