光纤Bragg光栅温度和应变传感特性的试验研究

Experimental Study on Temperature and Strain Sensing Characteristics of Fiber Bragg Grating

在光纤Bragg光栅传感原理的理论分析基础上,采用保温装置和等强梁结构对其温度和应变传感特性进行了试验研究,并做了试验结果的误差分析。其结果表明光纤光栅的Bragg波长随温度和轴向应变的变化呈现出良好的线性关系,且重复性较好。试验测得的温度灵敏系数升温时约为9.54 pm/℃,降温时约为9.53 pm/℃,理论计算值约为9.72 pm/℃;应变灵敏系数加载时约为1.006 pm/με,卸载时约为1.005 pm/με,理论计算值约为1.011 pm/℃;其试验值与理论计算值吻合得很好。同时介绍了一种简单实用的温度补偿技术,得出了考虑温度补偿后的实际应变与光栅波长的关系式,并采用焊接应力在线监测试验对其温度和应变传感特性的标定值进行了验证,为光纤Bragg光栅在铝合金工程结构中进行温度和应变监测提供了理论依据和试验数据,对光纤Bragg光栅传感测量的工程应用具有借鉴作用和重要意义。

On the basis of the theoretical analysis of fiber Bragg grating （FBG） sensing principle, temperature and strain sensing characteristics were investigated by attemperator and isodynamic intensity beam structure, and the error of the experimental results were analyzed. The results of experiment indicate that there is a good linear variation relationship between the wavelength of FBG and temperature or axial strain, and with a good repeatability. The experimental value of temperature sensitivity coefficient is about 9.54 pm/℃ at calefaction, and cooling at around 9.53 pm/℃, the theoretical value of that is about 9.72 pm/℃. The experimental value of strain sensitivity coefficient is about 1. 006 pm/με at loading and 1.1305 pm/με at unloading, the theoretical value of that is about 1. 011 pm/με. The experimental and theoretical values match well. Meanwhile, a simple and practical temperature compensation technology was intro- duced, the relationship between the wavelength of FBG and the actual strain of considering temperature compensation was obtained. And temperature and strain sensing characteristics of calibration values were verified with the experiment of on-line monitoring of welding stresses. It provided theoretical foundation and experimental data for the applications of FBG in the aluminum alloy structures of temperature and strain monitoring, and it will have important reference and significance for the engineering applications of FBG sensing monitoring.