An experimental study on the process monitoring of resin transfer molded composite structures using fiber optic sensors

Official URL: http://192.168.1.20/record=b1378282 (Table of Contents)

This thesis focuses on the research conducted on in situ process monitoring (cure and flow) of resin transfer molded glass fiber reinforced polymer composites using Fiber Bragg Grating (FBG), etched bare fiber optic sensors and Fresnel refractometers. In this direction, a laboratory scale resin transfer molding (RTM) apparatus was used with the capability of visually monitoring the resin filling process as well as embedding fiber optic sensors. Both FBG and etched fiber sensors are embedded into glass fiber rein-forcements in the RTM mold, and are used to monitor the flow front during the resin injec-tion and subsequently the cure cycle. Moreover, the cure cycle of the resin system utilized in this work is studied using an in-house developed Fresnel based refractometer. The data gathered from corresponding cure monitoring experiments have been compared with the results of polymer extraction experiments and excellent correlation between the results was observed. The embedded FBG sensors also allow the determination of mechanical stresses or loads on the in- service composite parts, through interrogating these sensors. This process is referred to as Structural Health Monitoring, which is not considered within the scope of this thesis work.