Research On The Deformation Monitoring Method And System For Rotating Blade Based On Fiber Bragg Grating

As the important component of rotating machinery, rotating blades'safety directly affects the overall safety of rotating machinery, and the failure of blade fracture often very serious, therefore it is very meaningful to monitor the state of working blade. While blade deformation is the most intuitionistic description of blade state, so one of the main contents is to research on monitoring methods for blade deformation in this paper.Fiber grating sensing technology is a sensing technology developing rapidly in recent years. Due to those advantages, such as no power and no electricity, anti-electromagnetic interference, long signal transmission distance, can work in inhumane working conditions which is inflammable, explosive, dusty and oily, large-scale distributed network measure easily be realized by using wavelength/time division multiplexing technology, fiber grating sensor has great application prospect in large mechanical equipment condition monitoring. And at present many researchers are studying on the problem how will fiber grating be applied to mechanical equipment condition monitoring.From the above, this paper is to research how to use fiber grating to monitor the rotating blades deformation. Design a kind of structure, seek a method to apply fiber grating sensing technology in monitoring rotating blades deformation, and to provide a new kind of considerations for the application of fiber grating in mechanical structure condition monitoring. For this purpose, the main work of this paper includes four aspects as following:1. Analysed blade structure and the stress state on working, researched the mechanism and form of blade deformation; the blade vibration characteristics and vibration deformation model were obtained by simulation analysis for the blade.2. Researched on the monitoring method in blade deformation using fiber grating, confirmed the sensing method and type of sensor to monitor deformation, and designed the sensor based on the fiber grating as sensing element. This part is the main content of this paper.3. Introduced the analysis and processing method of obtained signal by fiber grating sensor. First of all, this paper introduced the demodulation method of fiber grating signal, and then introduced the signal processing methods, including time-domain analysis and spectrum analysis and wavelet analysis.4. The static experiment and low speed experiment research for the sensor were carried out separately, which verified the feasibility of the method, and laid the foundation for the subsequent high-speed measurement.