Shape Reconstruction of Composite Structures Using High-Resolution Distributed Strain Data from Brillouin Scattering Based Optical Fiber Sensing System

Abstract

We have constructed a high-accuracy structural shape reconstruction system for global structural monitoring of large-scaled composite structures. The remarkable point of the algorithm is that we use high-resolution distributed strain data obtained by one of optical fiber strain sensing systems; pulse-prepump Brillouin optical time domain analysis (PPP-BOTDA) system. In this paper, a displacement reconstruction algorithm is constructed with the consideration of characteristics of distributed strain data, such as the influence of the spatial resolution and the measurement error distribution. In response, we adopted weighted least-square method to estimate strain distribution functions with adjusting weights for each sampling points corresponding to the reliability of data. The algorithm was applied to the estimation of beam bending deflections. Several strain data under different loading conditions were obtained by a beam bending test using a composite beam specimen with an embedded optical fiber. And then, the deflections under each loading condition were predicted appropriately.