Quasi-static indentation response of aramid fiber/epoxy composites containing nylon 66 electrospun nano-interlayers

In the last decade, polymer nanofibers have found promising application for improving through-thickness properties of structural composite laminates through interleaving. The main advantage of inserting nanofibers in conventional composites is making the matrix between the layers tougher. In this article, the benefits of using electrospun fibrous nano-interleaves in enhancing the quasi-static indentation response of aramid/epoxy laminated composites was investigated and the effect of variables of produced nano-interleaves including interleaf thickness (17.5, 35, and 70 µm) and stacking configuration (one-side, central, and two-side interleaving) on behavior of the nano-modified composites was investigated. The results indicate that force, displacement, absorbed energy, and stiffness of these composites are significantly affected by the presence of nano-interleaves. The optimum values were observed in the composites with 35 µm thickness of nano-interleave where three first parameters were higher than their reference values, but the stiffness value had opposite trend of other parameters. On the other hand, it can be seen that only asymmetrical (back-side indentation) stacking configuration lead to improving the composite properties. The visual inspection of the indentation damaged specimens reveals that thickness and stacking configuration of interleaves controls the size of damage.