Detection and Characterisation of Conductive Objects Using Electromagnetic Induction and a Fluxgate Magnetometer

Area of Science:

• Electromagnetism
• Materials Science
• Non-Destructive Testing

Background:

• Eddy currents are induced in conductive materials by time-varying magnetic fields.
• These currents generate secondary magnetic fields that can be measured.
• This phenomenon allows for non-contact material characterization and object detection.

Purpose of the Study:

• To investigate the frequency dependence of secondary magnetic fields generated by eddy currents.
• To evaluate the use of electromagnetic induction for characterizing conductive objects.
• To compare experimental results with numerical simulations.

Main Methods:

• Utilized a table-top experimental setup with a primary coil and fluxgate magnetometer.
• Generated oscillating magnetic fields up to 1 kHz to induce eddy currents.
• Performed numerical simulations to model the electromagnetic response of conductive objects.

Main Results:

• Detected aluminum and steel cylinders using the principle of electromagnetic induction.
• Observed frequency-dependent responses of conductive objects to the primary magnetic field.
• Achieved good agreement between experimental measurements and numerical simulations.

Conclusions:

• Eddy current testing is effective for identifying and characterizing conductive objects.
• The technique allows for non-destructive measurement of electrical conductivity and magnetic permeability.
• Frequency-dependent analysis enhances the capability of eddy current methods for material discrimination.