Low Frequency Accelerometer Of New Fiber Bragg Grating Design And Experimental Studies

It is of signality to study low-frequency vibration measurement in modern industrial field Vibrational damage detection is a critical issue in various engineering applications e.g., the safety monitoring of large-scale civil engineering and infrastructure, mechanical engineering and rail network system etc. Realizing a non-destructive health monitoring systems for such large infrastructure/engineering system systems is quite challenging. Vibrational damage monitoring systems such as accelerometer is one of the key smart-diagnostic systems which play a crucial role in such applications. At present, electromagnetism class accelerometers were mainly used to collect the low frequency vibration. However, the existing electrical accelerometers have inherent limitations to apply for such a purpose. Because of the distinct advantages, e.g., lightweight, small size, resistant to electromagnetic interference, high sensitive, wide band width, and environment ruggedness, fiber Bragg grating sensors have shown potential for displacing the existing traditional electrical sensors for the application such as vibration monitoring.On the base of fiber grating sensing technology and combination with general design method on accelerometer. Two novel low-frequency fiber bragg grating(FBG) accelerometers were designed and manufactured based on flextensional member and metal bellows structures. Has carried on the theoretical analysis and the experimental study to these plans. The amplitude-frequency relationship and the sensitivity of the accelerometer were gained through calibration tests with a commercial accelerometer. The results of the tests showed that the natural frequency and sensitivity of flextensional-based FBG accelerometer is 16.7Hz and 410.7pm/g; the natural frequency and sensitivity of metal bellows-based FBG accelerometer is 136.5Hz and 548.7pm/g pm/g. The index of the sensor met the theoretical value approximately The performance indexes of these sensors were then enhanced by optimized the possible mechanical parameters. As can be seen from the above results, the feasibility of the FBG accelerometers developed are satisfactory for low frequency vibration measurement (below 100Hz). Finally, on the basis of the above research work, a three-dimensional fiber Bragg grating accelerometer model was created, which can be proved theoretically.