Electromagnetic Acoustic Emission Characteristics of Aluminum Plates with Different Crack Sizes

In this paper, a mathematical model of electromagnetic acoustic emission is established by using electromagnetic eddy current principle and finite element method. The electromagnetic field of cracked aluminum plate is simulated numerically, and the influence of crack size on the Lorenz force at the crack tip is analyzed. Under laboratory conditions, electromagnetic acoustic emission experiments with different crack sizes are carried out. The results show that the amplitude parameters can determine whether there exists a defect or not in the specimen. In the frequency analysis, the high frequency component of the signal has a peak phenomenon, and the wavelet packet analysis is used to decompose and reconstruct the acoustic emission waveform. It is found that when the crack length or depth increases, the peak waveform and the peak voltage of the high frequency signal also increase gradually. The simulation analysis is in agreement with the experimental results.