Methodology for Mapping the Residual Stress Field in Serviced Rails Using LCR Waves

Young-In Hwang; Hyosung Lee; Yong-Il Kim; Ki-Bok Kim

doi:10.1007/s10921-022-00895-w

Methodology for Mapping the Residual Stress Field in Serviced Rails Using L_CR Waves

J Nondestr Eval. 2022;41(3):63. doi: 10.1007/s10921-022-00895-w. Epub 2022 Sep 8.

Authors

Young-In Hwang¹, Hyosung Lee^{1

2}, Yong-Il Kim^{1

3}, Ki-Bok Kim^{1

2}

Affiliations

¹ Non-destructive Evaluation Team, Safety Measurement Institute, Korea Research Institute of Standards and Science, 267 Gajeong-ro, Yuseong-gu, 34113 Daejeon, Republic of Korea.
² Department of Measurement Engineering, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, 34113 Daejeon, Republic of Korea.
³ Department of Nano Convergence Measurement, University of Science and Technology, 217, Gajeong-ro, Yuseong-gu, 34113 Daejeon, Republic of Korea.

Abstract

Non-destructive stress measurement by ultrasonic testing is based on calculating the acoustoelastic modulus obtained from the relationship between material stress and sound wave velocity. A critically refracted longitudinal (L_CR) wave, which is a bulk longitudinal wave penetrating below and parallel to the surface below an effective depth, is most suitable for ultrasonic stress measurement tests because it exhibits a relatively large change in travel time in response to a change in stress. In particular, the residual stress distribution through the thickness of the subject can be calculated if transducers of different frequencies are applied because of the characteristic of propagation to different depths of penetration depending on the frequency. The main purpose of this study was to visualize the internal or residual stress distribution through the thickness of rails using L_CR waves. To this end, L_CR probes with different center frequencies were designed and manufactured, and the residual stress values of an unused railroad rail and two used railroad rails operated under different conditions were calculated. This was done using the ultrasonic signals received from each probe, of which the distributions were mapped. Through these mapping results, different residual stress values could be calculated according to the depth. The differences in residual stress generation and distribution according to the conditions surrounding the contact between train wheels and rails, and their characteristics, were visualized and analyzed. As a result, it could be concluded that the non-destructive evaluation technique using L_CR waves could detect differences in the residual stress of a rail, and thus can be used to measure the residual stress of the rail accurately.

Keywords: Acoustoelastic effect; Critically refracted longitudinal (LCR) wave; Non-destructive evaluation (NDE); Railroad rail; Residual stress mapping; Ultrasonic testing (UT); Wheel-rail rolling contact.

© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022, Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.