Open crack depth evaluation using eddy current methods and GMR detection

In this paper the eddy current nondestructive method is used to determine the depth of linear cracks that were machined on aluminum plates. To improve this method a constant field probe was used to produce linear eddy currents launched across the crack. The tangential to plate magnetic field components perpendicular and parallel to the applied field were measured by a giant magneto-resistor sensor at different frequencies to devise one method for crack´s depth measurement.