Detection of fiber waviness in carbon fiber prepreg using Eddy current method

Abstract In order to control the quality of carbon fiber reinforced polymer in the production process, a method of detecting fiber waviness in carbon fiber prepreg using eddy current (EC) probe is proposed. The EC probe includes orthogonal rectangular coils. The excitation coil is parallel to the designed fiber direction, so that the output voltage of the reception coil is only related to the bending of EC caused by fiber waviness. The phase of the output voltage is used for characterizing fiber direction. The results show that the probe is able to distinguish fiber direction as small as 0.5° and fiber waviness in prepreg can be detected. Moreover, algorithm of reconstructing fiber distribution is proposed and fiber waviness is visualized.