Low-Velocity Impact Response of Nano-Silica Reinforced Aluminum/PU/GFRP Laminates

The bonding of metal sheets and Fiber-reinforced composites is called Fiber Metal Laminates (FML). In the current work, Polyurethane (PU) foam is inserted as a core material in FML, and E-Glass fibers enclose it. The exterior layers are of aluminum alloy 2024 sheets bonded by nanofiller dispersed in an epoxy resin matrix. The nano-silica is used as nanofillers dispersed in the epoxy resin matrix. Nano-silica of 1wt.% is used with epoxy for fabricating the NFML (Nano Fiber Metal Laminate). Laminates are fabricated by hand lay-up and compression molding at 180 MPa at 70 °C. The laminates are tested under low-velocity impact test using a drop weight impactor at different energy levels of 60 J, 80 J, and 90 J for a specimen size of 150 mm x 150 mm. The failure modes of aluminum sheet, PU Foam, and Composite laminate are studied. The results are compared between FML with and without nano-silica. The effect of nano-silica becomes significant in the laminate from 90 J impact energy. Below that, the pristine FML has a high impact force and withstands the impact load effectively. The failure sign of dent depth, delamination area on the rear side, and peak impact load are measured.