There is a need for a pulsed eddy current (PEC) to detect very small defects and deep buried subsurface flaws reliably in metallic structures such as aircraft wings. This paper reports an investigation into the sensitivity for a pancake PEC probe to variations in the material conductivity of specimens. Three experimental coil parameters are modelled: (a) coil inner radius, (b) coil width and (c) coil height. Based on the predicted signals, the sensitivity of the PEC probe as a function of coil parameters has been formulated. Through matrix numerical simulation experiments using orthogonal array, the weighting of each parameter to the sensitivity has been derived. Subsequently, a theoretical model for probe optimisation is established in order to realise the maximum sensitivity, based on which a probe is designed with improved sensitivity.
- finite element method
- probe optimisation
- pulsed eddy current
- electromagnetic nondestructive evaluation