Transient finite element modeling of magneto-optic imaging of aging aircraft

Magneto-optic imaging (MOI) is a relatively new technique implementing optical recording of magnetic flux leakage from surface and subsurface defects in both ferromagnetic and non-ferromagnetic metals. These techniques have gained widespread interest in the aviation industry for detecting cracks and corrosion beneath paint and other surface coatings. This paper presents transient finite element (FE) modeling of eddy current magneto-optic imaging, considering a typical inspection configuration of a subsurface crack initiating under the cap of a fastener. Implementation results are shown for different fastener material types and excitation pulse-width durations. Modeling is performed under ANSYS environment, and simulation results revealed that noticeable change exists in the vertical component of the magnetic field for adopted configuration. Developing of accurate FE models should enhance future developments of MOI systems for aging aircraft.