Finite element simulation study of signal characteristics of pulsed eddy current detection technology

Abstract

The principle of pulsed eddy current detection is the phenomenon of electromagnetic induction, and it is difficult to study pulsed eddy current detection technology through theoretical derivation due to the complexity of electromagnetic induction. Finite element analysis uses a mathematical approximation to simulate the real physical system, and at the same time, its use of simple but interacting elements makes it possible to approximate the real system of infinite unknowns through a finite number of unknowns. Finite elements not only have high computational accuracy, but also can adapt to a variety of complex shapes, and can easily deal with the advantages of nonlinear media properties. In the electromagnetic field and other problem-solving, it has a very wide range of applications. Therefore, this paper uses finite element simulation technology to design a pulse eddy current simulation model, using the model to study some parameters of the pulse eddy current detection model. Some conclusions can be obtained after several sets of experiments: (1) Whether the test piece has defects or not, the peak value of the detection voltage decreases with the increase of the inner and outer diameters of the coil. (2) Under the same inner and outer diameters of the coil, the peak value of the detection voltage with defects is smaller than that without defects. (3) The specific frequency of the pulse improves the sensitivity of the detection. (4) The bigger the lift distance between the coils and the measured parts is, the smaller the detection signal is. (5) The deeper the defect is, the lower the detection voltage is.