Application Of FBG Sensors For Fatigue Monitoring Of Advanced Polymer Matrix Composites

Abstract

The utilization of polymer matrix composites (PMCs) in the aerospace industry has increased over the last decade due to their high specific strength. The next generation of PMCs has the potential of being used for applications of elevated temperature (ET). Work conducted in this thesis is aimed at developing test methodology for the characterization of fatigue behavior of PMCs at ET. Conventional strain measurement techniques (e.g. strain gages and extensometers) have limited applicability during cyclic loading. An alternative strain sensing technology is the Fiber Bragg Grating (FBG) sensor. In this thesis surface mounted and embedded FBG sensors are used to monitor stiffness degradation and damage development in woven PMCs during fatigue loading at temperatures up to 200°C. Results demonstrate the applicability of FBGs for fatigue monitoring of PMCs in this temperature range. Also, the effect of temperature on the off-axis properties of PMCs is captured and discussed.