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 30 wt% of silica nanoparticles were fabricated. Quasi-static and dynamic compression tests were conducted on the brick composite specimens with fiber orientations of 0°, 5°, 10°, 15°, and 90° 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°, the fiber microbuckling is the dominant failure mechanism. On the other hand, for the 90° 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.