Abstract
We propose and verify a simple, convenient, and low cost method to inversely measure arbitrary strain distributions by applying a genetic algorithm approach to analyze the reflection intensity spectra of two fiber Bragg gratings (FBGs). The proposed method involves bonding one uniform FBG and one chirped FBG to the same location of the structure of interest such that they both encounter the same strain field. The arbitrary strain distribution within the fiber gratings is then determined inversely from the two Bragg intensity spectra by means of a genetic algorithm population-based optimization process. Also, we include the reflection power attenuation factors into the genetic algorithm and make this approach more useful in practical. Several strain distributions along the fiber Bragg gratings are reconstructed numerically. The proposed measurement method is suitable for many smart structure-monitoring applications.
