Effect of Conformable Substrate Thickness on an Eddy Current Sensor Array’s Output Characteristics

A finite element model of an eddy current sensor array is built up by electromagnetic-circuit couple method, and the influences of conformable substrate thickness on sensor’s output characteristics are analyzed by the model. It is shown that the amplitude of sensing coils’ output would diminish as substrate thickness increased, besides, the discrepancies of sensing coils’ output also decrease when the substrate becoming thicker. Therefore tt is necessary to make the conformable substrate as thin as possible in sensor fabrication process to enhance the crack inspecting ability of the sensor.