Experimental investigation on flexural behavior and energy absorption of lightweight sandwich panels with aluminum honeycomb core embedded by thin-ply carbon-glass fibers/epoxy face sheets

Generally, designing lightweight and thin -walled structures with high mechanical performance is one of the challenging issues for mechanical and civil engineering sciences. To this aim, sandwich panels which have been designed and analyzed in present research include aluminum honeycomb core (H) and UD-thin-ply carbon (C)/ glass fiber fabric (G) composite facings and investigated the effect of hybridization and stacking sequence on their static and dynamic mechanical properties while keeping thickness constant. Hybrid face sheets panels with three lay-up configurations of [G2C2G2H]s, [GCG2CGH]s, [CG4CH]s and non -hybrid configurations (i.e., [G4H]s, [C2H]s) were also produced as baseline. Series of 3 -point flexural tests, Charpy impact tests, visual inspection and scanning electron microscope (SEM) investigation were performed. The results showed improvement of the flexural strength, core shear strength, facing bending strength and static energy absorption of the [G2C2G2H]s in comparison with [G4H]s, by 100%, 109.1%, 59.87% and 70%, respectively. Furthermore, the dynamic energy absorption of the [GCG2CGH]s increased by 123.53%. The characterized failure mechanisms in the panels with the hybrid face -sheets were the delamination between plies; brittle fracturing of the carbon fibers, pulling out the glass fibers, deformation of the honeycomb's cell, and delamination between skin and core. Therefore, the results of this research can be helpful for designing lightweight and high mechanical performance sandwich panels which have thickness limitation.