FBG-based Strain Monitoring Studies

Compared with the traditional electric sensors, optical fiber Bragg grating sensor has many advantages, such as resistant to corrosion, strong anti-jamming capability, light quality, small volume, repeatability, widespread monitoring, etc.these advantages make it very suitable for applications in the train where the environment is very complex to monitoring the strain and vibration of the key parts. Research in the fiber Bragg grating structural health monitoring system to monitor the train running condition, and to ensure safe operation of the train has important significance.The main contents include:1. Based on Bragg equation and the theory of fiber grating, the temperature and strain sensing characteristic of the FBG have been analyzed, as well as the problems of temperature compensation.2. Design a kind of FBG vibration sensor based on the characteristics of fiber grating strain and uniform strength cantilever, improve the sensitivity of purpose by adopting FBG in parallel to fixed above a certain height of the cantilever beam.3. It's proved that the FBG vibration sensor has good vibration frequency response characteristics through the vibration test, and it's suitable for locomotive vibration monitoring.4. Establish the model of aluminium alloy beam and make a finite element analysis, according to the results of analysis to find the maximum strain fatigue fracture and the site for the pasted FBG strain sensors.5. By applying different loads of aluminum alloy beam, we get the key parts' strain value by the FBG strain sensors and the resistance strain gauge. Optimization model for again meshing finite element simulation results prove that the fiber grating strain monitoring and the reliability of the finite element analysis of the model.