Flexural performance of sandwich beams with lattice ribs and a functionally multilayered foam core

This study focused on the flexural behavior of an innovative sandwich beams with GFRP skins, lattice ribs, and a functionally multilayered PU foam core (GLF beams). The lattice ribs, consisted of longitudinal and horizontal ribs, were arranged along the longitudinal direction of the beam. Eight beams, involving a control specimen, were tested under four-point bending to validate the effectiveness of the lattice ribs and functionally multilayered foam core for increasing the ultimate bending strength, stiffness and energy dissipation ability. Test results showed that compared to control specimen, a maximum of 143% increase in the ultimate bending strength can be achieved. The energy dissipation ability of the beam was increased greatly by the use of lattice ribs and functionally multilayered foam core. Meanwhile, unlike the conventional sandwich beam, GLF beams failed in a ductile manner. Furthermore, an analytical model was proposed to predict the bending stiffness and ultimate bending strength of GLF beams. The analytical results were agreed well with test results.