MANUFACTURING OF CARBON NANOTUBE-EPOXY COMPOSITES AND TESTING OF THE PHYSICAL AND ELECTRICAL PROPERTIES

Abstract

The development of multi-functional smart materials has been rapid in the materials community in recent years. Shape memory nanocomposite material has been studied extensively. In this research, the epoxy resin-based shape memory composite material mixed with a multi-walled carbon nanotube (MWCNT) can change shape when stimulated by heat. Different designs of the printed nanocomposites and their ability to change shape without damaging themselves are explored. In addition, due to the presence of MWCNTs, the developed nanocomposite is electrically conductive and can be used as a strain and deformation sensor due to its piezoresistive sensing capability. The developed nanocomposite sensors are studied as embedded sensors for structural health monitoring (SHM) [1, 2], which is essential for providing real-time assessments of composite structures, enhancing safety, and extending their service life. Early damage detection through advanced nanocomposite sensors enables timely maintenance, reduces costs, and helps prevent catastrophic failures. This thesis introduces the synthesis, 3D printing, and characterization of novel embedded strain sensors using MWCNT-enhanced nanocomposites in fiberglass-reinforced composites for potential damage diagnostics and SHM applications. MWCNTs are dispersed within the structural epoxy to create 3D-printed nanocomposites with piezoresistive sensing capabilities. These sensors are embedded in fiberglass-reinforced composite laminates, and their performance is characterized under various maximum loads and load rates during three-pointx bending tests. Additionally, the long-term reliability of the strain sensors is evaluated over 1000 loading cycles. The recorded piezoresistive signals demonstrate high sensitivity to applied bending loads, with a gauge factor of up to 100, indicating strong potential for load sensing, in-situ damage diagnostics, and real-time SHM in structural composites.