Location

La Jolla, CA

Start Date

1979 12:00 AM

Description

In the design of a system for NDE, it is necessary to quantify the relationship of flaw size and orientation to transducer signal levels. This is particularly true for automated systems, in which the transducer coordinates cannot be adjusted by an operator to maximize the signal. This paper presents the result of a model calculation for the case of angle beam inspection using EMATs, which appear likely to find extensive use in such systems. Included in the model are calculations of the elastic wave radiation pattern in three dimensions for plates, calculations of the elastic wave scattering from cracks using existent approximate models, and calculation of the electrical response to the scattered wave. Transducer apodization is used to reduce spurious side lobe signals and "blind areas" where flaws are weakly detected. Emphasis is placed on the case of SH wave generation.

Book Title

Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE

Chapter

11. Fundamentals and New Techniques

Pages

384-385

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Calculation of the Response of Angle Beam EMATs to Flaws in the Far Field

La Jolla, CA

In the design of a system for NDE, it is necessary to quantify the relationship of flaw size and orientation to transducer signal levels. This is particularly true for automated systems, in which the transducer coordinates cannot be adjusted by an operator to maximize the signal. This paper presents the result of a model calculation for the case of angle beam inspection using EMATs, which appear likely to find extensive use in such systems. Included in the model are calculations of the elastic wave radiation pattern in three dimensions for plates, calculations of the elastic wave scattering from cracks using existent approximate models, and calculation of the electrical response to the scattered wave. Transducer apodization is used to reduce spurious side lobe signals and "blind areas" where flaws are weakly detected. Emphasis is placed on the case of SH wave generation.