Influence of hybridization on the mechanical and dynamic mechanical properties of aramid/S2-glass hybrid laminates

This work investigates the effect of hybridization and stacking sequence on the response of S2-glass/aramid/ epoxy interply hybrid laminates, focusing on flexural, short beam, dynamic-mechanical results and, especially, quasi-static indentation (QSI) properties. Different laminates of comparable thickness were manufactured by vacuum infusion, one with only aramid fabrics ([K](4S)), one with only S2-glass fabrics ([G](8S)) and six interply hybrids, namely [G(6)K(5)], i.e. six S2-glass layers on top of five aramid layers (asymmetric), [G(8)K(4)] [G(10)K3], [K(2)G(4)](S), [G(2)K](S2) and [G(4)K(2)](S). QSI tests were used to determine absorbed energy, maximum energy and peak load, and the in-plane damage was analyzed. Significant differences in mechanical and dynamic-mechanical properties (pairing effect) were observed for the [K(2)G(4)](S), [G(2)K](2S), [G(4)K(2)](S) and [G(8)K(4)] hybrids, and the adhesion factor (A) presented the closest correlation with energy absorption capacity of the laminates. The results have shown that hybridization of aramid composites with S2-glass may enhance impact absorption, and a positive hybrid effect was observed for the laminates with S2-glass fibers on the top surface, [G(6)K(5)], with peak load and absorbed energy (9.9 kN and 55 J, respectively) higher than that of the pure laminates [G](8S )(5.9 kN and 41 J) and [K](4S) (8.6 kN and 46 J).