Deflection Monitoring of Bi-Dimensional Structures by Fiber Bragg Gratings Strain Sensors

Abstract

In this paper, we report about the deflection estimation of bi-dimensional structure by using fiber Bragg gratings (FBGs) as strain sensors embedded in the structure and an algorithm based on the classical beam theory with small deformation assumption. The proposed technique allows a real-time indirect structural monitoring solving the existing difficulties in measuring the deflection directly and can be applied to small as well large structure, and it is crucial in high-energy physics, where particle detectors have to measure the position of the incoming radiation with a resolution of few tens of micrometers. The obtained results have been compared with mechanical comparator direct deflection measurements showing good agreement, showing a resolution of few tens of micronmeters over a surface of the order of about 1 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The dynamic range of deflection monitoring is dependent on the panel dimension: in the hypothesis of 1-m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> panel, the deflection limit is around 15 cm since FBG can measure very high strain (greater than 10000 μm/m).