2016 Volume 13 Issue 17 Pages 20160715
This paper presents a novel forced-resonance microwave technique to detect surface cracks in metal. This technique utilizes a cutoff cavity with a control element and a voltmeter to probe for surface cracks in the metal. Crack signals are detected by using forced resonance from the cutoff cavity probe. In the absence of a crack, the cutoff cavity probe aperture with a shorting plate (short-circuit) can resonate forcefully by adjusting the control element, and the forced resonance characteristics of the cutoff cavity are then probed by a detector (voltmeter) with voltage maximized. However, in the presence of a crack, the forced-resonance cutoff cavity probe aperture, in turn, changes the resonance properties from a short circuit, and the resonance variations are then detected by the detector as the voltage varies. The validity of this method was established by comparing experimental results with theoretical values.
