Study Of Fiber Bragg Grating Vibration Sensor Based On Composite Material Structure

Vibration sensors play an important role in many fields such as seismic detection,structural health monitoring and diagnosis,and security monitoring and early warning,whose performance directly affects signal quality and subsequent analysis results.In recent years,fiber optic sensors have been widely studied and applied for its various advantages,such as high sensitivity,anti-electromagnetic interference,wide dynamic range,small size,light weight,corrosion resistance,and easy networking,etc.Composite materials have good mechanical and physical properties and can be processed quickly by additive manufacturing techniques.It is worthwhile to overcome some shortcomings of electrical sensors and traditional materials and processing techniques by combining fiber Bragg grating(FBG)with composite materials and designing FBG vibration sensors with new structure and high performance.The main research contents of this paper are as follows:1.The research status and development trend of FBG vibration acceleration sensors at home and abroad are summarized and analyzed,and the significance and practical value of the combination of composite materials and fiber sensing are clarified.The sensing principle of fiber Bragg grating is studied,the mechanical model of FBG vibration sensor is established,and the main technical parameters of acceleration sensor are introduced.2.An FBG accelerometer based on compliant cylinder made of silicone rubber was developed.Theoretical modeling and finite element analysis were carried out,the sensor was packaged,the calibration test system was built,the software function module was written,and the parameter calibration test and the foot vibration test were carried out.The experimental results show that the natural frequency of the sensor is 70 Hz,the response flat area is 5-40 Hz,the sensitivity is 19.36 pm/g,and the linear coefficient is higher than 0.99.The cross-interference of the sensor is effectively controlled.The sensor has a good performance in detecting the footstep signal with a good low frequency response.3.An FBG accelerometer based on a composite structure with polyamide shell and sensitized elastomer was developed.Theoretical analysis and simulation were carried out,and the sensor was packaged and the sensor was calibrated.The experimental results show that the sensor has a natural frequency of 134 Hz,a flat response of 5 to 50 Hz,and a sensitivity of 12.6 pm/g.The foot test experiment verified that the actual performance of the sensor is good.4.An FBG accelerometer based on symmetrically bended spring plates was designed.The sensor was analyzed theoretically,the response characteristics of the sensor were simulated,the sensor was processed,the parameter calibration test was carried out,and the foot vibration test was carried out,and good results were obtained.The sensor has a natural frequency of 90 Hz and a flat response area of 3 to 65 Hz.The sensitivity is 25.7 pm/g.It has high sensitivity and good low-frequency response capability,and is resistant to lateral interference.It is suitable for low-frequency vibration detection.Finally,the content of the paper was summarized.The innovation points and deficiencies of the paper was analyzed and improved methods was proposed.