A novel microwave technique for detecting long surface cracks in metals is described. This technique utilizes an open-ended waveguide to probe the surface of a metal. In the absence of a crack the metal surface is seen as a relatively good short-circuit load. However, in the presence of a crack higher order modes are generated which in turn change the reflection properties at the waveguide aperture. This change brings about a perturbation in the standing wave characteristics which is then probed by a diode detector. The experimental and theoretical foundations of this technique are given, along with several examples. It is shown that cracks a fraction of a millimeter in width are easily detected at around 20 GHz or lower. Smaller cracks can be detected at higher microwave frequencies.
C. Yeh and R. Zoughi, "A Novel Microwave Method for Detection of Long Surface Cracks in Metals," IEEE Transactions on Instrumentation and Measurement, Institute of Electrical and Electronics Engineers (IEEE), Jan 1994.
The definitive version is available at http://dx.doi.org/10.1109/19.328896
Electrical and Computer Engineering
Keywords and Phrases
20 GHz; Crack Detection; Fatigue Cracks; Fatigue Testing; Long Surface Cracks; Metal Fatigue; Metals; Microwave Measurement; Open-Ended Waveguide; Perturbation; Rectangular Waveguides; Reflection Properties; Standing Wave Characteristics; Electromagnetic Formulation-Probe Development and Antennas; Surface Crack Detection and Evaluation
International Standard Serial Number (ISSN)
Article - Journal
© 1994 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.