Electromagnetic field calculations for the low frequency eddy current testing of tubular products

Low frequency eddy current technique, known as remote field eddy current (RFEC) technique, is being widely used for the nondestructive testing (NDT) of metallic tubes. Despite the early recognition, advantages and successful application in the in-situ inspection of oil well casings this technique lacked the development of an adequate theoretical base to help understand its complex phenomenon. Theoretical simulation of a practical RFEC geometry (moving probe inside a flawed tube) is described in this paper through the application of finite element numerical analysis technique. The predicted RFEC output traces show a higher and constant detection sensitivity irrespective of flaw depth, flaw location (ID or OD) and location of the sensor within the remote field zone.