Issue << content << Detection and Estimation of Transversal Cracks under Railhead Subsurface Exfoliations


DOI:

2015. . No. 2(68) - Jun 2015, pp. 68-73

Detection and Estimation of Transversal Cracks under Railhead Subsurface Exfoliations

V. V. Mosyagin, A. A. Markov, S. A. Pohorukov

Introduction. Resource-saving technologies, risk management and repair work based on the actual rail condition dictate the necessity of defect real size estimation for repair planning and residual life calculation. At the railway net there are scores of thousands of rails with surface defects which are not dangerous but at complete inspection are obstacles in the path of the ultrasonic beam. Dangerous transversal or horizontal cracks in the railhead that can lead to rail fracture often arise just beneath those defects. The article contains the results of the research aimed to increase reliability and accuracy of railhead crack parameters determination.
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
References
  1. Markov A. A., Kuznetsova E. A. Defektoskopiya relsov. Formirovanie i analiz signalov. Kn. 2: Rasshifrovka defektogramm [Flaw detection in rails. Signals generation and analysis. Book 2: Defectogram interpretation]. St. Petersburg, Ultraprint, 2014. 332 p. (in Russ.).
  2. Abdurashitov A. Yu. Tekhnika zheleznykh dorog [Railway Engineering]. 2012, no. 3(19), pp. 65–70 (in Russ.).
  3. Mosyagin V. V., Markov A. A. V mire NK [NDT World]. 2014, no. 4(66), pp. 11–14 (in Russ.).
  4. Hermen G. Image Reconstruction from Projections. New York, Academic, 1980.
  5. Markov A. A., Mosyagin V. V., Keskinov M. V. Russian J. Nondestructive Testing. 2005, no. 12, pp. 778-789.
  6. Markov A. A., Bershadskaya T.N., Belousov N.A. et al. Ultrazvukovoy sposob kontrolya golovki relsov [Ultrasound technique of railhead inspection]. Patent RF no. 2184374. Bull. Izobreteniy [Bulletin of Inventions], 2008, no. 34 (in Russ.).
  7. Markov A. A., Mosyagin V. V., Kuznetsova E. A. Put i putevoe khozyaystvo [Railroad track and track facilities]. 2013, no. 8, pp. 2 –9 (in Russ.).
  8. Markov A. A., Mosyagin V. V., Razorvin V. E. Ultrazvukovod [Ultrasonic path]. Patent RF no. 105742. Bull. Izobreteniy [Bulletin of Inventions], 2011, no.17 (in Russ.).
  9. Markov A. A., Mosyagin V. V., Kuznetsova E. K. Put i putevoe khozyaystvo [Railroad track and track facilities]. 2012, no.11, pp. 2–6 (in Russ.).
 
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