Development of nanocomposites for the ply-drop regions of glass fiber reinforced polymer (GFRP) composite structures

Date

2023-12-11

Author

Savaş, Doğa

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In the current study, incorporation of nanoparticle reinforcement in the matrix of glass fiber reinforced polymer (GFRP) composite structures, and its effect on the structural integrity of the ply-drop regions has been studied. In the GFRP composites used in applications such as wind turbines, ply-drop regions are created along the wind axis to adjust the thickness and, thus, the weight of the components. Damage formation in such composite structures usually occurs in these regions due to structural discontinuity caused by the ply-drop. Therefore, this study aims to improve the mechanical properties of the ply-drop regions in the composites by reinforcing their matrix (resin) with nanoparticles. In the scope of the experimental studies, nanoparticles such as functionalized carbon nanotubes (fCNT), cellulose nanofibers, and nanoclay have been used in different quantities to reinforce the matrix of the GFRP composite. Various combinations of GFRP composites with pristine epoxy matrix or nanocomposite matrix have been produced and compared. The best results were obtained by 0.35 wt% fCNT containing nanocomposite matrix with a 28% increase in fracture toughness while the strength remains constant. Moreover, mode I and mode II interlaminar fracture toughnesses of glass fiber reinforced composites with nanocomposite matrix were increased by 8% and 35%, respectively. Consequently, test specimens representing the ply-drop regions were manufactured using the developed nanocomposite with improved fracture toughness, and delamination tests were carried out to study the crack formation mechanisms in detail. As a result of these tests, although there was a decrease in tensile and delamination strength, work of fracture and failure strain were increased by 6% and 9%, respectively. Observed slight deterioration in tensile properties may be acceptable considering the advantages that the fCNT incorporation provides in the fracture behavior of the ply-drop regions.

Subject Keywords

Glass Fiber Reinforced Polymer (GFRP), Nanocomposites, Carbon Nanotube, Ply-Drop Regions, Ultrasonication

URI

https://hdl.handle.net/11511/107774

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Graduate School of Natural and Applied Sciences, Thesis