基于桥梁结构的FBG传感器温度与应变交叉敏感问题的研究

对光纤布拉格光栅(FBG)传感器在桥梁结构健康监测中产生的温度与应变交叉敏感问题进行了研究。采用参考光纤光栅法在应变传感光纤光栅附近额外加入一个温度测量光纤光栅,对应变光栅实现温度补偿功能。设计了基于参考光纤光栅法的FBG传感器及FBG传感器封装的机械结构,并通过实验来验证FBG传感器的性能。实验数据表明,温度传感光纤光栅几乎不受应变的影响,应变传感光栅的中心波长变化与温度变化呈一阶线性关系,修正后的测量结果更加精确,达到了双参数同时测量的目的,应变与布拉格波长的线性关系非常好,相关系数达到0.99以上。参考光纤光栅法能够很好地解决FBG传感器温度与应变交叉敏感的问题。

Sensitivity to temperature and strain of bridge structure of FBG sensor

Monitoring of temperature and strain for bridge structuture optical fiber Bragg grating (FBG) sensor was researched.The method of reference fiber Bragg grating was used.An additional temperature measurement fiber Bragg grating was added near a strain sensing fiber Bragg grating.As a result, it was not affected by stress.The strain grating is to realize temperature compensation function.The FBG sensor based on the method of reference fiber Bragg grating and the mechanical structure of the encapsulated FBG sensor was designed.The performance of FBG sensors is verified in the test.Test data show that the optical fiber grating temperature sensor is hardly affected by strain.Grating strain sensor is affected by temperature at the center of the wavelength with a first-order linear variation.The accurate measurement results were achieved.Two parameters are measured at the same time.The linear relationship of strain with the Bragg wavelength is very good.The correlation coefficient is above 0.99.The reference fiber Bragg grating method can solve the problem of FBG sensor which is sensitive to temperature and strain cross.