3-D finite-element analysis of eddy-current evaluation of curved plates

The eddy current method allows thickness evaluation of conductive plates. However, EC measurements are sensitive to multiple parameters such as the sensor liftoff and the plate curvature. In this paper, the plate curvature effect is studied using a three-dimensional finite-element method, and it is shown that the curvature effect cannot be corrected by a conventional liftoff effect correction. Consequently the curvature effect has to be specifically corrected in the measurement inversion. A correction method using bifrequency measurements is implemented.