Smart Railway Axle Box Embedded with FBG Sensor to Monitor Axle Temperature

초록

In this paper, we fabricated a smart axle box embedded with FBG sensor which can monitor the axle temperature on board continuously in real time. In comparison with other sensing technologies, FBG sensor provides many advantages including light weight, small size, and immunity to electromagnetic interference, long distance monitoring, wide measurement range, and independence from applied circumstances. The smart axle box consists of axle box housing, axle bearing, and the cover embedded with two FBG sensors. Two FBG sensors (OS3111 and OS4210, Micron optics, US) are embedded on the prefixed position inside the axle box cover. These sensors can be connected serially to the FBG logger (SFI-710 interrogator, FIBERPRO corp.) due to the multiplexing characteristics with different wavelength each other such as 1545 nm, 1552 nm. One of the FBG sensors detects the dynamic strain from the axle bearing, and the other FBG sensor detects the overheated axle temperature. To determine the temperature sensitivity of FBG sensor, wavelength shift was measured in reflection with a wavelength resolution of 0.1 pm. FBG sensor was heated in the oven and the temperature was measured with a resolution of 0.1℃ by a thermocouple connected to a thermometer (FLUKE 52K). The relative wavelength shifts of FBG sensor was acquired by increasing the temperature from 20 to 80℃ in increments of 5℃. Subsequently the smart axle box cover embedded with FBG sensor was inserted in an oven to evaluate the measurement accuracy of the axle box temperature. Temperature setting and the experimental set-up was the same with the case of the FBG temperature sensitivity measurement.