Design and optimisation of mutual inductance based pulsed eddy current probe

Abstract

High lift-off inspection arising from thick insulation and requirement to protect probe from weld zones are challenges to pulsed eddy current (PEC) testing. In traditional PEC probe with fixed coil gap, weakening interaction between probe and test sample as lift-off increases reduces sensitivity. To analyse this influence, numerical simulation and experiments on design and optimisation of driver-pickup PEC probes are carried out. Results validate that both coil gap and lift-off have significant effects on resultant mutual inductance of driver-pickup PEC probes above test samples. In addition, the probe sensitivity is enhanced at a higher lift-off when coil gap exceeds a certain value. The increase in detection lift-off with coil gap could be optimised.