FBG分布式非均匀应变重构准确度分析研究

以剥层算法为基础,分别从非均匀解调应变大小、重构算法的特征参量以及光栅初始结构参量等对光纤布喇格光栅应变重构准确度的影响进行相关研究分析.结果表明:工作长度为5~30mm的光纤布喇格光栅最佳应变解调在3 000με以内,在该应变解调范围内,保持光栅剥层的分层长度为0.1mm左右时,应变重构准确度和效率较优,折射率调制幅度越小,应变重构误差越小;同时,对于非均匀应变检测使用的强光栅,折射率调制幅度约为0.000 12时,应变检测结果最好.本文的研究结果对提高非均匀应变的重构准确度具有重要的指导意义.

Analysis on the FBG Distributed Non-uniform Strain Reconstruction Precision

Based on the LP (Layer Peeling) algorithm,the important influence factors on the reconstruction precision of the Fiber Bragg Gratings non-uniform strain,including the demodulation range of FBG non-uniform strain,the characteristic parameters of LP algorithm and the Fiber Bragg Gratings structure parameters,were numerically analyzed.From lots of simulating experiments,the results show,that the best proper strain demodulation is less than 3 000 με of Fiber Bragg Gratings with normal working length of 5～30 mm,and keeping the fractional length of nearby 0.1 mm for LP reconstruction algorithm can obtain the best precision of strain reconstruction.Remaining above conditions,it is found that the non-uniform strain reconstruction error is smaller when the refractive index modulation decreases,and for the strong grating,the refractive index modulation amplitude of approximate 0.000 12 is the best choice in Fiber Bragg Gratings non-uniform strain sensing.The results obtained here have certain guiding significance for improving the accuracy of Fiber Bragg Gratings non-uniform strain reconstruction.