Buckling and cracking of steel rails is a contributing factor in accidents on railroads today. Detection and notification of buckled track sections before a train reaches these locations will significantly increase rail safety. A fiber-optic-based sensing system, with the fiber affixed to a beam, was developed and evaluated to detect buckled regions. The purpose of this research is to evaluate the sensitivity of the fiber-optic sensing system to buckling of a long structural member. Numerous facets of fiber-optic sensing have been explored. Fiber-to-steel bonding techniques were examined and tested. Full-scale laboratory testing was conducted by elastically buckling a 24.4-m-long (80-ft) wide-flange section with hydraulic rams. Typical measurement accuracy within 10 percent of theoretical predictions was achieved by optical time domain reflectometry techniques. For field testing, however, a more robust solution is sought and is currently under development. It is suggested that a lower-cost fiber break or bend detector is a suitable option. The optical fiber will break or bend at the location of rail elongation in the buckled area, allowing the detection equipment to locate the buckled area.
Faseroptische Überwachung von mechanisch deformierten Kabelgeflechtsstrukturen mittels optischer Zeitbereichsreflektrometrie / Fiber-optic monitoring of mechanically deformed cable structures by means of optical time-domain reflectometry
