Enhanced FBG sensor-based system performance assessment for monitoring strain along a prestressed CFRP rod in structural monitoring

Fiber Bragg grating (FBG) sensor-based systems have been widely used for many engineering applications including most recently a number of applications in structural health monitoring. It is well known that strain and temperature both affect the FBG spectrum which in the interrogation system will be converted to a conventional electronic signal. This procedure provides the means for the FBG-based sensor system to be used for several monitoring applications. The aim of this research is to improve an existing monitoring system which has been used for several field test inspections. A brief description of the existing FBG-based system and the evaluation of the software developed to be compatible with a resolution reaching as high as ±0.15 μɛ is presented. The system has been tested under particular conditions where a prestressed CFRP (carbon fiber reinforced polymer) rod to which a FBG sensor is attached is used. The test procedure and results obtained are discussed in some detail.