Rub-Impact Signal Monitoring of Rotating Machinery Based on Fiber Bragg Grating Sensing

Rub impact acoustic emission (AE) technology has the characteristics of high sensitivity, wide frequency response range, and rich frequency components. Fiber Bragg gratings (FBG) with excellent detection features such as anti-electromagnetic interference, small size, light weight, and high sensitivity was used for the detection of rubbing acoustic emission from rotating machinery. A nut screw rubbing device for generating rubbing AE signals and a FBG demodulation system based on tunable laser were designed. Experiments on the detection of static and dynamic rubbing signals of rotating machinery using FBGs and phase shifted fiber Bragg gratings (PS-FBG) have been carried out. Experiments have shown that compared to piezoelectric ceramics, FBG can simultaneously sense the rotational speed and rubbing AE signals of rotating machinery, and have more abundant signal characteristics. The strength of the detected signal meets the requirements of online monitoring.