Optimized design of flaw detection method based on pulsed eddy current testing

Abstract

Eddy current testing technology is widely used in traffic safety, and different excitation sources will affect the amount of information and test results of a single test result. According to the characteristics of square waves containing multiple harmonics, using pulse eddy current detection, based on the analysis of the working principle of pulsed eddy current detection, the 60 kg/m I-shaped rail is used as the object, and the model is established using ANSYS. The simulation compares the advantages and disadvantages of traditional eddy current testing and pulsed eddy current testing at the same damage depth, analyzes the effect of pulse excitation duty cycle on detection sensitivity, and uses curve fitting to optimize the design of the excitation source duty cycle. The results show that: 1) Compared with traditional eddy current testing, pulsed eddy current testing has a larger magnetic induction line coverage area and deeper sinking depth near the rail damage, so the information amount of a single detection is more abundant; 2) The impact of the excitation duty cycle on the sensitivity of defect detection is related to the depth of damage; 3) The detection sensitivity is optimal when the duty cycle is 20%, and the peak voltage of the receiving coil is 1.72V at this time.