热残余应力对内埋光纤光栅传感器性能的影响

将布拉格光纤光栅(FBG)埋植于复合材料T型加筋板结构非干涉区—三角填充区作为应变传感器对复合材料加筋板在固化过程及冲击后压缩过程中的应变变化进行监测。对比了光纤刻栅区采用UV光固化树脂涂层保护和未保护的两种FBG传感器的波谱信号变化; 分析了复合材料在固化成型过程中产生的非轴对称热残余应力对FBG传感性能的影响。结果表明, 刻栅区采用聚合物涂层保护的FBG传感器的半峰宽(FWHM)在固化过程中未发生变化, 并且聚合物涂层可以有效地消除非轴对称热残余应力对光纤光栅反射波谱的影响。在冲击后压缩过程中, 采用聚合物涂层保护的FBG传感器测得的应变与贴于试样表面的应变片测得的应变数据一致性较好。本文对埋植于复合材料加筋板三角填充区的FBG传感器在复合材料固化过程及冲击后压缩过程中应变监测的有效性及可靠性进行了有益的探索。

Effect of thermal residual stress on fiber Bragg grating sensors embedded in T-stiffened panels

To monitor the strains of the composite T-stiffened panels during its curing and compression after impact, the fiber Bragg grating(FBG) sensors were embedded in the triangle area of the composite T-stiffened panels(structure non-interference region). The reflection spectra obtained from the uncoated FBG sensors and the FBG sensors coated with UV-cured resin were compared, and the effect of thermal residual stress on the reflection spectrum was studied. It was indicated that the full width at half maximum(FWHM) value of the coated FBG sensor almost unchanged during the curing, and the thermal residual stress upon the reflection spectrum can be attenuated by coating UV-cured resin on the FBG sensors. Furthermore, the strain measured by the coated FBG sensor is correspondence to the results of the strain gauge on the composites surface. The validity of the strain measured by FBG sensors was verified during the curing and the compression after impact.