NDTnet 1998 Aug, Vol.3 No.8

Full-Text - Abstract

A new idea for self-focusing of a linear array has been used for Rayleigh and Lamb waves. The self-focusing procedure automatically moves the focal region towards the defect that produces the largest backscattered signal by adjusting the excitation times of the elements of the array. Experimental results demonstrate the effectiveness of this method. The experimental results were confirmed by a theoretical model. Starting from the characteristics of a single array element, the sound field of the entire array is simulated by superposition. To complete the measurement model, the ultrasonic reflection from a surface-breaking crack was simulated and compared to experimental observations.

Figure 1. Steps of the self-focusing procedure a) firing center element, b) receiving with all elements, c) determination of time-of-flight differences, d) transmission focusing, e) reception focusing, and f) superposition gives focused signal.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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