Mod II fracture mechanics of nanoparticle reinforced laminated composite materials

Continuous fiber-reinforced polymer laminated composites are widely used in advanced engineering applications. While laminated composite materials are highly resistant to in-plane loads, they are less resistant to out-of-plane effects. Especially with out-of-plane impact, layer separations (delaminations) occur between layers. Out-of-plane loads also cause propagation of delamination and failure of the material. The interlaminar shear stresses that are the result of bending load, are the main reason for the delamination growth and the interlaminar fracture (mod II fracture). To increase the mode II interlaminar fracture resistance, some methods reinforce the material with a third component perpendicular to its plane. These methods, on the other hand, can negatively affect the in-plane mechanical properties by damaging the continuous fibers in the composite material. For this reason, investigations to increase the mode II interlaminar fracture resistance by reinforcing laminated composite materials with nanoparticles have become interesting in recent years. Increasing the fracture resistance of polymer matrix-rich volumes between layers is the main motivation of these researches. In these studies, it is also aimed to increase the adhesion force between the reinforcement fiber and the polymer matrix by adding nanoparticles. In this project, the mode II interlaminar fracture behavior of carbon nanotube modified E-glass/epoxy laminated composite materials will be investigated. The epoxy matrix will be reinforced by using three different types of carbon nanotubes at five different weight ratios. The effects of sizes and weight ratios of the carbon nanotubes on mod II fracture toughness and crack propagation in the carbon nanotube modified composite materials will be examined. The effects of carbon nanotubes on the fracture surfaces of the epoxy matrix and the epoxy and E-glass fiber interface will be observed. Keywords: Mode II Fracture Toughness, Carbon Nano Tube (CNT), E-glass fiber, Composite materials, Epoxy