Embedded Sensors for Next Generation Composite Materials

Abstract

This master’s thesis presents the development and optimization of next generation embeddable sensors for aerospace composite monitoring. All work was done in collaboration with the NRC’s Quantum and Nanotechnology Research Centre, NRC’s Aerospace Research Centre, and the University of Ottawa’s Lessard Research Group. This thesis is divided into 4 chapters; a literature review, which highlights the importance of this research, the key aspects of embedded sensing, and compares existing embedded measuring technologies for composite materials, drawing attention to the fact that all existing technologies present drawbacks in the form of elevated costs, high complexity, low resilience, extreme sensitivity to factors such as temperature and pressure, and most critically, degrading the structural integrity of the composite material in which they’re embedded. The second chapter shows a proof of concept for next generation sensors, which would have small enough footprint to not affect the composite performance, as well as be resilient enough to survive throughout the entire service life of the component, regardless of conditions faced. These sensors proved to be effective in measuring a common manufacturing defect known as ply migration, with an accuracy of 0.6mm. The third chapter proposes the second generation of the embedded sensors, which aimed to improve their performance to the point of being able to measure strain and damage to the composite, whilst retaining all the abilities from the previous generation. This was achieved through an improved shape and sensor architecture, with the ability to measure return signal loss when the composite was under stress, and a permanent loss when the composite suffered damage to its matrix. Lastly, the conclusion provides an insight into future work to be done and recaps the advancements achieved throughout the course of the research.