Sizing Technique for Slots and Surface Cracks in Metals


After a crack on a metal surface has been detected, determining its width, depth, and length becomes an important practical issue for fracture analysis and repair considerations. Having used a novel microwave technique for surface crack detection, two methods for sizing are introduced, namely a single frequency and a swept frequency method. The tradeoff between these two techniques is between hardware simplicity and high measurement accuracy, particularly when determining crack depth. The details of these two techniques are given with several numerical and experimental results. The width of a crack is shown to be measured within ±20 percent. However, the crack depth, the most important parameter in crack sizing, is shown to be measured with an accuracy of better than 1 percent, independent of the accuracy of the width measurement, using the swept frequency technique.


Electrical and Computer Engineering

Keywords and Phrases

Crack Characteristic Signal; Crack Depth; Cracks; Metals; Slot Cracks; Surface Cracks; Surface Crack Detection And Evaluation

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 1995 American Society for Nondestructive Testing, Inc., All rights reserved.

Publication Date

01 Apr 1995

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