Study of Fiber Bragg Gratings (FBG) as Acoustic Emission Sensor to Inspect and Monitoring Fiber-Glass Reinforced Polymers (FGRP) Degradation

摘要

Fiber-glass reinforced polymers (FGRP) exhibit characteristics such as excellent chemical resistance and low weight which make their use specially attractive for a series of indrustrial applications, which include pressure vessels and pipes. However, a considerable inconvenience for the application in critical components is the lack of inspection and monitoring methods that allow structural integrity evaluation in a reliable and efficient manner. The objective of this work is the development of a method capable of inspection and monitoring based on acoustic emission (EA) using Fiber Bragg Grating (FBG) to be applied in the detection of failure and degradation of composite components made of FGRP. This new method has advantages over conventional acoustic emission methods: there is no risk of explosion in classified environments, immunity to magnetic field noise, low attenuation of the light pulses even for long distances and multiplexing capabilities. The first stage of this work consisted in the development, manufacture of the FBG sensors and characterization. After approval, the sensors were used to monitor the damage progression in a pipe segment under fatigue loading and results were compared to the data obtained with conventional EA sensors. The propposed method proved to be viable with great potential although further studies are required for sensibility optimization.