双Fabry-Perot干涉腔型光纤声发射传感器

Fiber-optic acoustic emission sensors with dual Fabry-Perot interferometric cavities

设计了一种新型的双Fabry-Perot腔光纤传感器用于材料损伤引起的声发射信号检测。基于低细度Fabry-Perot腔多光束干涉原理,建立了光纤Fabry-Perot传感器检测声发射信号的数学模型。分析双Fabry-Perot腔正交点稳定工作机制,设计并制作了具有双Fabry-Perot腔结构的光纤声发射传感器来保持传感器正交点的稳定性。通过模拟AE信号检测与热应力干扰实验对设计的传感器进行了实验验证。实验一通过冲击振动与折断铅笔芯产生两类模拟声发射信号,使用商用的压电传感器和光纤传感器进行对比实验,结果表明光纤传感器能够成功检测到两类模拟声发射信号,灵敏度为12.9nm,带宽达到30kHz。实验二对传感器进行工作点稳定测试,结果表明双F-P腔的控制机制能够保证传感器工作在正交点,解决了传感器输出信号衰减的问题。

A novel fiber-optic sensor with dual Fabry-Perot（F-P）cavities was reported to detect the Acoustic Emission（AE）signals induced by the damage in composite and metal materials.A sensing model for detecting the AE signals of the fiber-optic sensor was established based on the multi-beam interference principle of the low finesse F-P cavity.The operating mechanism for stabilizing the quadrature-point of the dual F-P cavity sensor was analyzed,and then the fiber-optic sensor with a dual F-P probes was designed and manufactured to maintain the stability of the quadrature-point.The operating performance of the designed sensor was verified by two types of experiments on simulating AE signal detection and thermal stress interference experiments.In the first experiment,two kinds of AE signals were generated by shock vibration and breaking pencil leads and they were detected and compared with a piezoelectric sensor and a optical fiber sensor.The test results show that the optical sensor successfully measures the simulated two kinds of AE signals and it possesses a sensitivity of12.9nm and a frequency response of 30 kHz.In the second experiment,the stability of operating points of the sensor was detected,and the results indicate that control mechanism of the dual F-P cavities ensures the sensor to operate at the quadrature-point,and overcomes the signal attenuation of the sensor outputs.