Reconstruction of Non-Uniform Strain Along FBG Based on Dynamic Particle Swarm Optimization

Aircraft structural health monitoring is an important development direction of PHM technology. In order to understand the non-uniform strain distribution of the wing for condition monitoring, a dynamic particle swarm optimization (DPSO) algorithm for retrieving the non-uniform strain field of FBG is proposed in this paper. The algorithm uses the transfer matrix method to calculate the reflection intensity spectrum of the non-uniform strain and optimizes the strain profile by using the calculated reflection spectrum. In order to accelerate the convergence speed of PSO and avoid falling into local optimal solutions, dynamic inertia weights are used. The reconstruction accuracy of DPSO and PSO is measured for linear, higher-order and sinusoidal strain distributions. Finally, an experimental study is carried out on the cantilever beam with deflection, and the results of reconstruction are compared with those of finite element analysis. The effectiveness of DPSO algorithm and reflection spectrum for non-uniform strain reconstruction is verified, which provides a possibility for using non-uniform strain information to monitor the condition of wing structure.