Influence of PU foam reinforcement of I-beam on buckling resistance

The paper presents the influence of PU foam on the buckling resistance of an I-beam made with sheets aluminum alloy 6061-T6 sheets and GFRP plates. Four beam types were considered: an aluminum beam, a composite aluminum-fiberglass beam, a composite aluminum-fiberglass-PU beam and a composite aluminum-fiberglass-PU-ribs beam. Each beam was made with two C-profiles connected by webs, with flanges reinforced by flat bars. Channels were made by bending 0.8 mm thick aluminum alloy 6061-T6 sheets. Flat bars were made from aluminum alloy 6061-T6 2.0 mm in thickness. The metal sheets components were connected by Refill Friction Stir Spot Welding RFSSW technology. The composite aluminum-fiberglass beam additionally has GFRP plates glued to the flanges. The 3.0 mm thick GFRP plates were connected by a polyurethane adhesive. The composite aluminum-GFRP-PU and aluminum-GFRP-PU-ribs beams have a rectangular cross-section. The composite aluminum-GFRP-PU beam was made like the composite aluminum-GFRP beam, but with stiffening of the web by polyurethane foam. The aluminum-GFRP-PU-ribs beam was made like the composite aluminum-GFRP beam, but with stiffening of the web by aluminum ribs and polyurethane foam. The PU foam filled up the I-sections in such a way that rectangular cross-sections were obtained. The beams were subjected to three-point bending tests.