Abstract
Rail transportation is one of the most important and efficient forms of transportation. Large thermal strain can develop in the rail steel due to extreme climatic conditions resulting in safety related issues. We carried out a thermal-strain monitoring test on the rail specimen over a large temperature range from −40 ∘ C to +50 ∘ C using a Brillouin optical time-domain analyzer (BOTDA) for the first time, to the best of our knowledge. Two jacketed fibers and small-diameter carbon/polyimide-coating single-mode fiber were used for the purpose of investigating the jacket effect of thermal-strain detection on the rail. Although a nonlinear response to the temperature of the loose jacketed fiber was found, it was applicable for thermal strain monitoring when glued on the surface of the rail sample. The measured thermal strain in the rail specimen was validated by the results obtained by the strain gauge. The thermally induced strain from the large rail specimen was found to have suppressed the nonlinear impact of the fiber jacket.
Highlights
Rail transportation is one of the most important and efficient forms of transportation.Railway networks are fixed structures that can span many thousands of kilometers
A high spatial resolution-distributed optical fiber sensor based on Brillouin scattering is a very promising technique for this application
This paper reports the continuous thermal-strain monitoring of the rail steels using a Brillouin optical time-domain analyzer (BOTDA) for the temperature range between −40 ◦ C and +50 ◦ C
Summary
Rail transportation is one of the most important and efficient forms of transportation. The measurement is compared to the reference that is obtained by the strain gauge implemented on the middle of the steel rail This is the first time that optical fiber was used to monitor rail thermal strain in such a broad temperature range, to the best of our knowledge. When glued onto the rail to detect thermal strain, the measured Brillouin frequency shifts of all fibers exhibited a linear relationship with the temperature change, albeit with lightly different slope coefficients. This was attributed to the dominant thermal strain of the rail track that turned out to suppress the fiber jacket-induced nonlinear response of the Brillouin frequency shift, validating their applicability in distributed optical fiber strain sensing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
