An Application Of Anew Electromagnetic Sensor To Real-Time Monitoring Of Fatigue Crack Growth In Thin Metal Plates

this paper will only concentrate on performance characteristics and applications of the probe. Fig. 1. Schematic diagram of the self-nulling probe. V Magnetizing Coil A.C. Voltmeter Current Source Pick-up Coil Flux Focusing Lens (a) (b) (c) Fig. 2. (a). In-air pickup coil output (b). Nulled pickup coil output when the probe is positioned on a crack-free region of an aluminum plate (c). Pickup coil output at a crack due to a disturbance in the balance among the competing effects that caused the nulling of the output shown in (b)