Research On The Eddy Current Effect And Its Compensation Based On High Speed Electromagnetic Rail Inspection

With the development of high expressway, the quality of track becomes more and moreimportant. Finding a new way to detect the track sufficiently and effectively is vital. However, theeddy current effect restricts the application of magnetic flux leakage testing. This paper is focused onthis topic and includes some research work below.Firstly, the present status and problems of high railway and common nondestructive testingmethods are given. The principles of electromagnetic NDT and eddy current effect are mainlydiscussed in this part. Based on finite element theory and electromagnetic theory, two instantaneoushigh speed electromagnetic detect modules of three dimensional are founded by Ansoft MaxwellSimulation Software. Eddy current effect has little influence on module one, so module one is used asMFL testing model which can minimize eddy current effect. Conversely, Eddy current effect has greatinfluence on the module two, so module two is used to design a new structure which can utilize theeddy current effect in high speed.Secondly, two high speed detect platforms are formed based on the two models which are used totest the crack of track. Based on the characteristic values of experimental data in platform one, amethod of RBF neural network is introduced to eliminate the eddy current, which is also vary withdifferent speed. From the data of platform two, a method of evaluating the defect depth and thevariable of angle in the rail trend are verified.Both from the simulation and experimental results in the two platforms, we can find that when ina low speed which is only above30m/s, the accuracy of model one is decreased and the other model ismore accurate when the speed become higher. In the end, we utilize different platforms when thespeed is above or below30m/s, which is a complementary method.