Development of sensor based on GMI effect for structural health monitoring of engineering component

The present investigation deals with the development of magnetic sensor based on giant magnetoimpedance (GMI) effect using soft magnetic Co₇₀Fe₂Si₁₃B₁₅ amorphous wire as sensing core element. The GMI property of the sensing element has been utilized for development of the sensor which is sensitive to the minute variation of the local magnetic field. An embedded system comprising of hardware and software have been designed and developed to monitor and record the output signal of the sensor. The sensor output is calibrated against the external applied magnetic field. The sensor demonstrates its excellent linearity, repeatability and reproducibility.

The GMI sensor is very much useful for detection of the localized magnetic field of service exposed engineering components exposed to an external magnetic field and more specifically, this GMI sensor can be efficiently used for efficient monitoring of structural integrity of engineering components. The conventional non-destructive techniques such as ultrasonic, eddy current, magnetic particle inspection are also used to assess the defects or cracks of engineering components. However, all those methods are unsuitable for monitoring structural degradation as most of the structural components used in industries are of ferromagnetic steel and also the microstructural properties of the components due to their long service period, influence the magnetic and mechanical properties as well. Therefore, the GMI sensor may be more useful to detect the changes of local magnetic field of the aging structure owing to the microstructure changes of the component and thereby, monitor the structural health of the engineering components.