埋入式光纤Bragg光栅径向应力传感性能参数分析

Parameter Analysis on the Radial Stress Transfer of Fiber Bragg Grating Embedded into Metal Beam

埋入式光纤Bragg光栅(FBG)可以监测结构内部的应力、温度等其它参数。针对镀镍保护的FBG经钎焊方法横向埋入矩形截面的金属梁内部的情况,本文将影响FBG中心波长变化的因素归纳成两大因素——应力传递系数和位置函数,并深入分析了这两个因素对埋入式FBG的径向应力传感性能的影响。经研究得出,对于某一特定的连接层,尽量选取弹性模量大的保护层,适当减小保护层厚度有助于提高埋入式FBG应力传感的灵敏度。对于一定结构形式的梁,在应力传递系数一定的情况下,位置函数越大,埋入式FBG应力传感的灵敏度越大。埋入过程会造成位置误差。分析得出,当FBG实际埋入位置较指定位置偏右时,位置函数随着倾斜角度的增大而变大;当实际埋入位置较指定位置偏左时,位置函数随着倾斜角度的增大而变小。

Embedded FBG sensors can detect the internal state of stresses,temperatures and many other factors as an alternative to the other sensors.Before being embedded into the metal structures,FBG sensors must be protected by some metal materials.The discrepancy exists between the stress values recorded by FBG and the actual stresses.This paper relates the discrepancy to the two parameters that are the stress transfer coefficient and the location function.For a special connecting layer,the bigger elastic modulus and the smaller thickness of the protective layer,the bigger the stress transfer coefficient.When the FBG is embedded on the right of the designated position,the location function gets big with the increase of the tilt angle.When it is on the left of the designated position,the location function gets small with the increase of the tilt angle.