Digital Eddy Current Tomography for Submarine Pressure Hull Inspection Through the Coating

A capability to inspect submarine pressure hulls through the special hull treatment could result in significant savings in maintenance costs and improvements in fleet readiness. This poses a challenge for conventional nondestructive evaluation (NDE) methods, as acoustic methods are defeated by the coating and others require access to the surface. This proposal focuses on evolving MWM-MR-Array (Meandering Winding Magnetometer-Magnetoresistive) technology for application to the thick structure typical of submarine hulls by completing advancements in both sensor and instrumentation initiated under the Phase I effort. In addition, hull-like samples ranging from simplistic plates to panels with welded structure will be used to develop and evaluate detection and characterization capabilities of introduced flaws. Flaw characterization methods based on 3-D models and multivariate inverse methods will be used to enable digital eddy current tomography. JENTEK's MWM-Arrays have delivered superior performance for a variety of NDE tasks. JENTEK's engine component inspection systems, for example, in use by NAVAIR at several depots, have been called the"gold standard"due to their capability to detect flaws in hard-to-inspect areas missed by other NDE methods. This proposed effort will benefit from complementary programs, funded by Chevron and USDOT, focusing on inspecting pipelines through coatings and insulation.