光纤光栅检测非均匀壁厚圆管应变的实验研究

Experimental study of detecting the strain of round pipe with non-uniform wall based on Fiber Bragg Gratings (FBG)

根据光纤布拉格光栅(FBG)的传感原理,提出了一种基于光纤布拉格光栅技术的无损检测管柱应变的方法。设计制作了模拟管,模拟管的一侧壁薄,另一侧壁厚;将2个中心波长不同的光栅粘贴在管的这2个区域;实验测定了两光栅反射波长随压力变化的特性。结果表明,布拉格反射波中心波长漂移随压力变化呈良好的线性关系,壁薄处FBG的反射波长偏移量比壁厚处反射波长偏移量大,即壁薄处应变大。该方法不仅可检测非均匀壁厚圆管的应变,还可以检测其他复杂结构的应变,并可以用在恶劣环境,实现实时检测。

A novel method of detecting strain of non-uniform wallpipe based on Fiber Bragg Gratings (FBG) is presented according to the sensing principle of FBG. A simulating pipe was made with one section thin and another section thick. Two FBGs with different central wavelength were glued in the two areas of the simulating pipe. The feature of the change of the reflection wavelength of the two FBGs with pressure was measured during the experiment. The test result indicated that the change of the drifting of the central wavelength with pressure showed good linear relationship. The offset of the reflection wavelength at the thin wall section was more than that at the thick wall section, that is, the strain at the thin section was larger. This method can not only detect the strain of round pipe with non-uniform wall, but the strain of other pipes with complex structures. It can also be used in the severe environment for real-time detection.