Smart Carbon-Fiber Reinforced Polymer Optical Fiber Bragg Grating for Monitoring Fault Detection in Bearing

This article describes the development of a fiber Bragg grating (FBG) sensor encapsulated in carbon-fiber reinforced polymer to detect faults in rotating electrical machine bearings. The proposed sensor was based on the temperature and strain sensitivity of the FBG sensor and the robustness of carbon fiber as an encapsulation. The sensor was composed of three FBGs, one of which was packaged in a glass tube. The behavior characteristics of the developed sensor were evaluated in the calibration process. The experimental setup and measurement system were discussed and analyzed under dynamic conditions. The sensor was implemented in an induction motor operating at a controlled full load. The tests were performed with new and faulty bearings. The results, for the faulty bearing frequencies of 147.5, 296.6, and 439.0 Hz, were identified. These frequency components were generated by defects in the inner raceway. Comparing the amplitude spectrum between the signal of the new and faulty bearing, a variation of approximately 96% was found. The FBG reinforced sensor can identify bearing integrity in real-time and be a preventive maintenance tool for bearing monitoring.