Use of subminiature eddy current transducers for composite inspection

The sensor for studying composite materials of the metal-polyethylene-metal type was developed on the basic of the designed ultra-miniature eddy-current transducer. The test of the developed sensor was carried out on standard defects of composite materials in the form of an inhomogeneity defect in the metal and (or) polyethylene layer. This sensor uses the original converter design, produced according to the differential circuit with the ability to localize the contact area of the sensor and the material up to 0.1-0.5 mm2. The measurement procedure for detecting defects in composite materials is also given in the article. The article presents the correlations of the output signal of the developed sensor based on the aluminum-polyethylene-aluminum composite material, in which the defect was located. We also obtained standard images of model defects of a composite such as a layered discontinuity. The images obtained as a result of processing information from the developed sensor make it possible to draw conclusions about the topology of the field near violations of the internal structure, the type of this violation and its localization in layers of material.