INVESTIGATION OF THE SIGNAL INSERTED INTO A SUPERPOSED TRANSDUCER BY A DEFECT IN THE FORM OF A CENTRAL HOLE, IN DEPENDENCE ON THE SIZE OF THE DEFECT, THE THICKNESS OF THE SPECIMEN, AND THE DEGREE OF THE EDGE EFFECT

The article describes a method of solving the problem of calculating an electromagnetic field excited by a coil with ac and situated above the end face of a coaxial cylinder of arbitrary dimensions with a central through hole. The results of computer calculations are interpreted with the aid of hodographs of the relative signal. The article also shows differences in the shape of the hodographs determined by the size of the defect, the thickness of the specimen, and the degree of the edge effect.