Rail Bottom Defect Detection Device Based On EMATs

The detection results of rail defects are closely related to the safety of rail transportation.Nowadays,piezoelectric transducer is widely used to detect the internal flaws of the rail while it is faultful.It cannot work without acoustic couplant which affects its detecting speed.In addition,its big size?complex equipment and low detection precision also affect the production efficiency.Electromagnetic acoustic transducers(EMATs)can work without couplant and it has simple structure.It can improve the detection area and efficiency with guided wave detection.So it is of f great practical value to the safety of rail transportation and social harmony and stability.There have been some achievements in the field of rail flaw detection at home and abroad.On this basis,combined with EMATs and guided wave detection technology,this paper develops a rail bottom defect detection device based on EMATs,which can realize comprehensive flaw detection of rail bottom.According to the characteristics of irregular rail geometry,ultrasonic transducer was designed and the probe layout was designed to realize no blind spot in rail bottom detection.According to the characteristics of weak detection signal,high-power transmitting circuit and noise-reducing receiving circuit are designed,which can significantly enhance the echo signal and eliminate some interference.According to the characteristics of noise sensitivity of electromagnetic ultrasonic transducer,echo signal processing algorithm is designed,compared the actual detection effect and efficiency of two correlation detection algorithms,namely cross-correlation algorithm and autocorrelation algorithm.Finally,autocorrelation algorithm is selected as the signal processing algorithm of the device.Finally,the electromagnetic ultrasonic rail bottom defect detection system designed in this paper is used to detect the defects on the standard test block of the rail.