Sensing of Structural Damage with OBR Based Fibre-Optic Networks

Abstract

Optical fibre networks based on optical backscatter reflectometry i.e. the OBR technology is a new and promising method for the inspection of safety critical structures. It utilizes regular telecommunications grade optical fibres as sensors, and off the shelf equipment for sending and receiving light through the fibres. The signals can then be interpreted to reveal strains or temperature in the host structure. For this work, the optical fibre sensors were embedded inside composite shells during manufacturing. Experiments on axisymmetric demonstrators (pressure vessels, cylindrical tubes) show how the location, the severity, and the shape of impact damage can conveniently be visualized. Such information can serve as input for decision makers in condition based maintenance. Remaining challenges regarding practical embedding procedures and the signal interpretation are briefly discussed.