聚合物封装光纤布拉格光栅传感器温度压力特性研究

Temperature and Pressure Responsive Characteristics of Polymer Packaged Fiber Bragg Grating with Large Dynamic Range

分析了聚合物封装光纤布拉格光栅(FBG)传感器温度与压力响应特性。通过实验对某种特殊聚合物封装光纤光栅的温度与压力响应进行研究,发现当温度变化范围较大时,由于温度对材料弹性模量的影响,光纤光栅的压力响应灵敏度不再为常数,而是随温度变化的。当温度在 30℃时,其压力响应灵敏度为 0. 036 nm/MPa,在180℃时则变为0 .175 nm/MPa,且灵敏度系数随温度的变化呈分段线性变化。因此在使用聚合物封装实现光纤光栅传感器增敏以及大范围温度和压力的同时测量时,需要将弹性模量作为温度的函数,代入光纤光栅温度与压力响应灵敏度系数矩阵公式中以消除大范围温度变化对聚合物力学特性的影响。

The pressure and temperature response characteristics of polymer packaged fiber Bragg grating (FBG) sensor are analyzed. The experimental results show that the pressure sensitivity is not a constant but a variable because of the effect of temperature on elastic modulus of polymer when the change range of temperature is large. The pressure sensitivity is 0.036 nm/MPa at 30°C and 0.175 nm/MPa at 180°C and the change of sensitivity is piecewise linear at different temperature range. So elastic modulus should be treated as the function of temperature when using polymer to packaged FBG, the pressure coefficient in the coefficient matrix of FBG should also be the function of temperature in order to eliminate the error induced by the change of elastic modulus caused by large range temperature change.