Magnetoresistive-Arrays for Low Frequency Eddy Current Imaging of Buried Corrosion

ABSTRACT:Corrosion of aluminum aircraft structures affects remaining life and safety . When corrosion occurs below the surface of exterior panels, current inspection methods require panels to be removed and replaced. An inspection method is needed that eliminates the necessity of removing exterior aircraft panels. The proposed effort will develop an inspection system capable of rapid, wide-area inspection of aluminum substructures through aluminum or composite exterior panels. It will build on JENTEKs magnetoresistive magnetometer array (MR-MWM-Array) technology and use multiple frequencies to estimate material loss, via JENTEKs HyperLattice multivariate inverse methods. The objective is to detect corrosion loss of 0.02 in. depth by 0.075 in. diameter on the buried, near surface of a 0.25 in. thick aluminum substructure through 0.2 in. thick aluminum or 0.5 in. thick IM7 5240-4 composite skins. This will be demonstrated in Phase I and extended in Phase II to address specific Air Force needs. JENTEKs latest 8200 series instruments provide significant improvements over predecessors, such as lower frequencies; simultaneous operation at multiple frequencies; high data rates; 119 parallel channels; improved signal-to-noise; and ergonomic/software improvements, including reduced size/weight. These technological advances will allow rapid, wide-area scanning for corrosion, cracks, and other flaws. BENEFIT:If the proposed SBIR program is successful the Air Force will have a new capability to perform a rapid, wide-area, corrosion inspection of hidden structures. The capability to account for variability in skin thicknesses and internal structure geometries and provide reliable sizing of corrosion defects is needed for a wide range of military platforms. This program will complement JENTEKs ongoing successes in other markets, such as Oil & Gas for corrosion imaging and together have a broad impact on safety and costs.