Development of self-diagnostic composite structures using embedded Fiber-Bragg Grating sensors .

摘要

The use of composite materials in large structures has grown rapidly over the past decade. Consequently, the need to identify a technique for robust structural health monitoring of these composite structures has arisen. Developing composite structures that are capable of diagnosing their own structural health using embedded sensors would allow proper monitoring of structural integrity and further increase the advantages of working with composites. Fiber--Bragg Grating (FBG) sensors have been used to monitor the structural health of composite structures in real--time and are well suited to the task due to their non--intrusive size and multiplexing capability.;In this thesis, the durability of embedded FBG sensors is first explored through tension and impact testing. The effect of non--uniform strain on the embedded FBG sensor is investigated through the implementation of a numerical analysis that can predict a reflection spectrum when given a non--uniform strain distribution. It will be shown that a new proposed reflection spectrum interrogation method will improve crack detection capability. The new interrogation method is validated by multiple experiments in which embedded FBG sensors are used to monitor crack propagation in composite specimens using various geometries. Health monitoring capabilities are extended to thick--section composite panels with multiple FBG sensors to detect and monitor impact damage. The use of embedded FBG sensors is found to be an effective method of structural health monitoring in multiple applications.