Magnetic Imaging And Current Mapping For NDE Of Aluminum Components On Ships

New technology is needed for nondestructive evaluation (NDE) of defects in aluminum structures on ships. Fatigue cracks at weldments where defects may be hidden under paints, rough surfaces and other materials are especially problematic. An NDE technology capable of imaging defects in welds under a variety of surface conditions would be ideal. Existing NDE technologies such as visible imaging, x-radiography and acoustic emission cannot provide the portability, rapid imaging, moderate equipment cost, and simple operating protocols needed. Eddy current testing (ECT) is highly sensitive to cracks in aluminum, but it is sensitive to lift-off at rough surfaces and does not image defects. RMD proposes a revolutionary new eddy current imaging technology based on magnetic imaging and current mapping to automatically detect and characterize cracks, corrosion and other defects in rough metallic components. A 2-D sensor array will generate magnetic images of eddy currents. Current mapping will allow the system to be used with rough surfaces without susceptibility to lift-off. The NDE system will be portable, versatile and simple to operate and interpret. The proposed NDE technology will improve ship integrity and safety, and reduce the cost and complexity of inspections. It will also characterize incipient defects and defect propagation.