Real-Time and <i>In Situ</i> Monitoring of FRP by Rayleigh Scattering-Based Distributed Sensing

Abstract

In-situ monitoring method of FRP (Fiber Reinforced Plastics) by built-in sensors is a key technology for developing future and high-reliable composite structures. The Rayleigh scattering-based distributed optical fiber sensor has high spatial resolution of 1mm and good embeddability into FRP and then it can be considered that the sensor is very suitable to in-situ monitoring of FRP. In the present paper, process monitoring and damage identification of FRP were conducted. In the process monitoring, flow-front of silicon oil impregnating into glass textile during VaRTM (Vacuum-assisted Resin Transfer Molding) process was measured. Comparing to visual observation results, it appeared that the maximum slope position of strain distribution showed flow-front position. In the health monitoring, damage identification of cross-ply GFRP laminates with delamination by the attached distribution optical fiber sensors was carried on. From the results, it was found that the strain varied largely on the delaminated section and then the delamination was detectable from the surface strain distribution measured by the optical fiber sensor.