The Detection Technology Of Rail Defects Of Phased Array Ultrasonic Imaging

The train will be produced friction and extrusion with rail in the process ofbraking and acceleration, then the rail will appear crack and constantlyexpanding over time, that is likely to cause serious traffic accident. China has alarge population which has large amount transportation, it is very important todetect the flaw of steel rail.This paper access to a large number of ultrasonic flaw detection data, theauthor applied ultrasonic phased array technique to rail flaw detection. Thetechnique arroding to control the excitation of each element of the time delaywhich has completed the deflection and the focused beam of a range, then thereis no need to move the probe on the rail flaw. This paper focuses on the analysisof phased array sound field, including the wedge sector scan delay algorithm andrail defect sector imaging algorithm. Then the author proposed a method toanalyze the quantitative defect. The main work of this paper are as follows:This paper analyses the principle and performance of phased array, andbuilds the mathematical model of ultrasonic transducer. Through simulation andanalysis, it turns out the rectangular plane ultrasonic transducer sound fielddistribution. Based on the characteristics of the sound field distribution theauthor sets the optimal parameters transducer. Sound field distribution and theparameter setting lay the foundation for ultrasonic phased imaging.In this paper, the author analyses the characteristics and selection methods,proposes the defect sector scan detection scheme which contains wedge;Wedge sector scan trigger algorithm, Sector scan echo receiving algorithm, Raildefect quadrant imaging algorithm were deduced, the algorithm implementationscheme and geometry graphic was given.In this paper, in order to improve the effect of image enhancement the original signal was proceeded under dynamic filter process and interpolationapproach was used on the image; Finally, localization analysis was carried on thedefect of the image to improve the accuracy of defect detection.