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 will develop rapid 3-D crack models and multivariate inverse methods for crack length, depth and location imaging to provide digital eddy current tomography. JENTEK’s Meandering Winding Magnetometer (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. The JENTEK/DoD team was awarded the 2007 FAA-ATA “Better Way” award for this system. This proposed program will benefit significantly from complementary programs currently funded by Chevron and USDOT. These three year programs, focused on inspecting pipelines through coatings and insulation, will address some of the obstacles that must be surmounted to achieve digital EC tomography, such as the large stand-off distance, while this proposed program focuses on crack and flaw modeling and imaging.