Multi-Modal Hole Inspection Using Eddy Current Arrays and Surface Topology Imaging

Nondestructive evaluation of internal surfaces of holes or pipes in steel structures, such as evacuator holes in gun tubes, for the presence of surface flaws such as stress corrosion pits and cracks is a difficult task, particularly when the internal space is small, the structure is large and rapid inspection with high precision is desired. The process is further complicated by the presence of surface features such as pits, which can be difficult to separate from true crack indications. While this dilemma can be prohibitive to any single technology, through a fusion of two methods it is possible to enhance detection capability. JENTEK proposes to test and compare two surface topology mapping methods (such as MWM-Array surface mapping or an optical or capacitive sensing method), each in combination with the MWM-Array crack detection method. The trade-offs between performance, cost, and inspection time will be evaluated. A framework for data fusion will be developed which will simplify data analysis for the end user.Using the surface topology images, surface features such as pits will be used to filter the MWM-Array data to enhance crack detection and suppress noise.Feasibility of delivering a rapid, low cost, and practical solution will be demonstrated.