Response Analysis of a Plate Structure under Double Source Excitation by FBG Sensors

The nondestructive assessments play a key role for condition monitoring of in-service structures. At present, many non-destructive testing methods have been widely applied, but actual operation environment has the characteristics of multiple random, which makes the effects of multiple excitation sources. While the traditional detection methods only consider the main sources of motivation and ignore the other sources, which will bring a bigger error. So the multi-source excitation method has practical significance. Here this paper puts forward a double source excitation technique for plate structure based on fiber Bragg grating sensor, which is used to receive the waves in the plate. First, measuring principle of double source excitation and demodulation principle of the FBG sensor are introduced. Then simulation analysis in the double source excitation field is devoted, whose results lay the foundation for the detection in the plate. On this basis, the experimental system is built and the influence of different parameters are analyzed such as frequency, phase. Then this double source excitation-FBG sensing technique is applied to damage detection by envelope analysis, whose result show that this double source excitation-FBG sensing method for the plate structure is sensitive to crack damage