2015. . No. 2(68) - Jun 2015, pp. 68-73
Detection and Estimation of Transversal Cracks under Railhead Subsurface Exfoliations
Method. The article gives a way for calculation of plane cracks location, length and angle based on through signal ultrasonic test (an amplitude-shadow technique). To confirm the way given, computer simulation of a shadow technique acoustic path has been carried out with the specially developed program Rail 3D, and crack parameters have been calculated with the program MathCad.
Results. The flaw detector has been specially developed for detection and evaluation of transversal cracks under railhead surface damages; the results of its operation during 2015 are given. It is shown that the flaw detector confidently reveals dangerous transversal cracks under horizontal subsurface exfoliations with a measurements error less than 15% (the depth of a defect lower edge and a defect size in a railhead cross-section were measured). Over reject of rails is practically impossible, and this enables the life time of rails with nonhazardous defects to be prolonged.
Conclusion. Sizing of cracks located under surface damages and testing results documentation allow the rails with nonhazardous defects to be left in the way and monitored.
Keywords: nondestructive testing, ultrasonic flaw detection, railhead, crack sizing, through signal ultrasonic test, shadow technique
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