Numerical investigation on arbitrary strain distribution sensing with fiber Bragg grating-based Sagnac interferometer and genetic algorithm

This study presents a numerical investigation into a novel approach for the inverse measurement of arbitrary strain distributions using a genetic algorithm (GA) and a fiber-Bragg-grating-based Sagnac interferometer. In the proposed method, a single uniform fiber Bragg grating (FBG) is bonded to the structure of interest such that it encounters the arbitrary strain field. The arbitrary strain distribution is then determined inversely from the transmission intensity spectrum using a GA population-based optimization process. The major advantage of the proposed approach is its use of a single, uniform FBG to sense arbitrary strain distributions. The approach provides a low-cost and computationally efficient means of detecting strain distributions in many smart-structure monitoring applications.