Modelization of cracks in steel subsea structures-application to the optimization of a new electromagnetic detection method

A novel contactless electromagnetic nondestructive testing technique has been developed for the detection of cracks in offshore steel structures. In order to optimize the detection device, a crack model using existing software based on a finite elements method has been proposed. The electrical activity of the modeled crack, interpreted as a back electromotive force (BEMF) source, is investigated. A two-level approach leading to a simplified modeling makes the investigation of this BEMF possible by reducing the size of the numerical problem. Results lead to the understanding of defect magnetic signal shapes and thus to the design of an optimized detection device