On the Flexural Behavior of Multiscale Nano-Silica/E-glass/Epoxy Anisogrid-Stiffened Composite Structures

Grid-Stiffened Composite (GSC) structures have attracted considerable attention and popularity in a variety of aerospace and other applications, in which reliability and mass efficiency are critical issues. On the other hand, a significant improvement in fibrous polymeric composites can be obtained by incorporating a very small amount of nanofiller in the matrix material. Here, we reported an experimental study on the reinforcing effect of silica (SiO2) nanoparticles on the flexural properties of E-glass/epoxy GSC panels with an anisogrid lattice patterned reinforcement. Improving the mechanical behavior of nanocomposites requires good dispersion of the nano-silica in the matrix. To do so, high-intensity ultrasonication and mechanical stirring techniques were employed in the present work. The flexural behavior of the multiscale panels was characterized by quasi static 3-point bending test. The variations of flexural stiffness, load bearing capacity, and energy absorption of the specimens according to the silica loading in the epoxy matrix (0, 1, 3 and 5 wt.%) were assessed. Results indicated that multiscale composite panels had better flexural properties with respect to the silica-free one. The effect of the present of silica in the matrix was reflected by acceptable increase in stiffness, load bearing capacity, and energy absorption by 17%, 15%, and 28% in the case of 3 wt.% silica-loaded specimen. Taking into account the conclusions reported in this paper, it confirms that the incorporation of the silica nanoparticles is an efficient strategy to improve the flexural characteristics of a fibrous GSC structure.