Investigating Silica Nanoparticle Effect on Dynamic and Quasi-static Compressive Strengths of Glass Fiber/Epoxy Nanocomposites

The research is aimed to investigate the compressive strengths of glass/epoxy nanocomposites, containing various loadings of spherical silica nanoparticles. Through a sol-gel technique, the silica particles with a diameter of 25 nm were exfoliated uniformly into the epoxy resin. Subsequently, by inserting the silica-epoxy mixture into the unidirectional glass fiber through a vacuum hand lay-up process, the glass fiber/epoxy composite laminates with 10, 20, and 30wt% of silica nanoparticles were fabricated. Quasi-static and dynamic compression tests were conducted on the brick composite specimens with fiber orientations of 0 degrees, 5 degrees, 10 degrees, 15 degrees, and 90 degrees using a hydraulic MTS machine and a split Hopkinson pressure bar, respectively. Observations on the failure specimens indicated that for fiber orientations less than 15 degrees, the fiber microbuckling is the dominant failure mechanism. On the other hand, for the 90 degrees samples, the out-of-plane shear failure is the main failure mechanism. In addition, it was denoted that as the silica contents increase, the compressive strengths of the glass/epoxy composites are improved accordingly. The enhancing mechanism in the compressive strengths can be properly explicated using the microbuckling model.