Study Of FBG-based Flaw Monitoring In Wheelset Tread

Compared with the traditional electric sensors and fiber optic sensor, Fiber Bragg Grating(FBG) has the advantages of high accuracy, strong antijamming ability, moistureproof effect, corrosion resisting, small dimension, light weight, and division multiplexing, making it quite extensive in the field of railway safety monitoring where the detection conditions is very complex because of the strong interference, limit space and various parts. It is profound to research in the FBG monitoring system in the field of railway safety to dynamic monitor the condition and enture the stability and safety of the train. The main contents include:1. We use bare FBG and steel encapsulated FBG to test the strain of steel structures. The experiment verifies that the FBG sensing system has accuracy and feasibility in steel structures testing..2. We establish a scheme of flaw detecting in wheelset tread according to the analysis of the strain of rail. We design a detection scheme which can monitor the strain of rail with high precision and continuation. We choose a suitable way of encapsulation and layout.3. We monitor the strain of rail when there is a train running on it and analyse the waveform of the strain. We compare the sensibilities of sensors in different position and determine the best layout position by the analysis above.4. We improve the encapsulation and layout technology of FBG sensors to acquire the best laid distance. The results show that the FBG sensor system used in this experiment can distinguish the angle of5degree on the wheelset tread of common rail train.