A ROTATING CANTILEVER BEAM FOR DYNAMIC STRAIN MEASUREMENT AND VIBRATION ANALYSIS BASED ON FBG SENSOR

Strain measurement and vibration analysis of a rotating blade are critical for the progress in improvements of the performance of machines. Since traditional sensors and measurement methods have difficulty measuring the rotor blade's dynamic strain and vibration, the search for new measurement methods has become an urgent task in rotor machine monitoring and diagnosis. This paper presents a new method based on Fiber Briggs Gratings (FBG) for the measurement of strain and estimation of vibrations in a rotating cantilever. The method is based on the fact that the vibration displacement can be expressed in terms of an infinite number of vibration modes and be related to the dynamic strains through strain-displacement relationship. By placing multiple sets of FBG and utilizing an optic coupler, the rotating cantilever beam's dynamic strain can be measured and vibration can be estimated at the same time. From the results, it can be concluded that this new monitoring method is applicable to the rotating blade.