FBG传感器应变监测温度效应分析

Efficiency analysis of strain monitoring temperature of FBG sensors

光纤Bragg光栅(FBG)在土木工程健康监测中得到广泛应用。依据光纤光栅Bragg方程,从理论上分析了光纤光栅应变和温度传感的工作原理,阐述了光纤光栅应变和温度双参量共同作用时引起交叉敏感的物理机理;并结合济南奥体中心体育馆钢结构健康监测中应变监测的相关数据,分析了温度效应对应变测量的影响。结果表明:在应变测量中,温度场偏差是影响应变测量误差的主要因素,温度补偿时温度场的选取要保证温度与应变传感器所处温度场一致,一阶温度灵敏度系数对Bragg中心波长漂移的影响几乎是应变灵敏度系数的10倍;但应变和温度的交叉敏感效应及其二阶项效应的影响一般可以忽略。

The fiber Bragg grating（FBG） has found wide and better application in the civil engineering.On the basis of the FBG equation,the work principles of the FBG strain and the temperature sensing are analyzed theoretically,and the physical mechanism is elaborated of the cross-sensitivity caused by the double-parameter interaction of the FBG strain and the temperature.And with the related data of strain monitoring of steel structure health monitoring of Jinan Olympic Sports Center Gymnasium,the effect to the strain measurement from temperature effect is analyzed.The results shows that temperature field deviation is the main factor of strain measurement errors and temperature field must be selected to ensure that temperature and strain sensors are consistent with temperature field.The effect of first-order temperature sensitivity coefficients to Bragg wavelength drift is almost 10 times bigger than that of the strain.However,cross-sensitivity strain and temperature effects and second order effects can generally be ignored.