Measurement of multi-axial stresses using a phase-shifted FBG and the adaptive particle swarm optimization algorithm

A method utilizing one Phase-shifted Fiber Bragg Grating (PS-FBG) and adaptive particle swarm optimization (APSO) algorithm has been proposed to simultaneously measure the spatial multiple axial stresses, including axial stress and transversal stress. The swarm success rate based dynamic adaptive strategy for the adjusting of inertia weight has been introduced to balance the exploration and exploitation. To validate the method, six cases of spatial multiple axial stresses have been simulated, and the simulated spectra of PS-FBG have been reconstructed using APSO and traditional PSO. The simulation results indicate the APSO based reconstructing method is capable of estimating the simultaneously applied axial strain and transversal forces, and provides higher accuracies compared with traditional PSO. The experiments have been performed to verify the above mentioned method. The experimental results demonstrate that the APSO can effectively reconstruct the spectral profiles of the PS-FBG. The error of axial strain is 4.49με and it is 1.24N for transversal force.