Axial and lateral buckling analysis of kevlar/epoxy fiber-reinforced composite laminates incorporating silica nanoparticles

The aim of this study was to experimentally determine the effect of silica nanoparticles (NS) on the buckling characteristics of Kevlar/epoxy fiber reinforced composite laminates. The composite samples with different weight fractions of NS particles, namely 0.0, 0.5, 1.0, 1.5 and 2.5 wt%, were prepared by vacuum assisted resin transfer molding (VARTM) and subjected to axial and lateral buckling tests. Additionally, the buckling tests were performed on the samples with different lengths (125, 150, 175, 200 and 225 mm) to analyze in more detail the influence of NS fractions on axial and lateral buckling performances. Morphology and failure mechanisms of the samples were analyzed using scanning electron microscopy images of critical regions of each sample. The results showed that the incorporation of NS particles led to higher critical buckling load values for both axial and lateral buckling. The highest critical buckling load values for both axial and lateral buckling events were observed for 1.5 wt% NS particle content in Kevlar/epoxy composite laminates. Further increasing of NS resulted with the decrements in critical buckling loads because of poor interfacial bonding between NS particles and epoxy resin, primarily due to onset of agglomeration. As it is expected the decreases in length of samples resulted with significant increases in both the axial and lateral buckling characteristics. The results of this research can be used to design composites with high buckling resistance, especially for applications where loading may compromise structural stability and functionality, such as tall buildings, structural bridges and roofs, rail tracks.