Non-destructive crack detection using GMI sensor

Abstract

In this study, the variation of the magnetic flux distribution in a magnetised ferromagnetic material which has inhomogeneity as a crack is studied using giant magnetoimpedance, GMI, sensor. The sensor was moved by a specially designed moving system. The amorphous (Co0.94Fe0.06) 72.5Si12.5B15 wire was used as a GMI sensor and 1 MHz with 5 mA ac current applied to the GMI sensor. A large decrease in the output voltage of the sensor circuit was observed when the sensor was moved on the top of the crack, after the further movement of the sensor the output voltage came back to the nearly previous value.