Mechanical performance of foam-filled lattice composite panels in four-point bending: Experimental investigation and analytical modeling

This study focused on the bending behavior of an innovative sandwich panels with GFRP face sheets and a foam-web core (GFFW panels), manufactured by vacuum assisted resin infusion process. An experimental study was carried out to validate the effectiveness of this panel for increasing the ultimate bending strength. Compared to the control specimen, a maximum of an approximately 410% increase in the ultimate bending strength can be achieved. The influences of web thickness, web height and web spacing on failure mode, initial bending stiffness and mid-span deflection were also investigated. Test results demonstrated that the ultimate bending strength and initial bending stiffness can be enhanced by increasing web thickness and web height. In the meantime, the indentation failure and local wrinkling failure did not occur due to the presence of the GFRP webs. Furthermore, an analytical model was proposed to predict the mid-span deflection and initial bending stiffness of GFFW panels. A comparison of the analytical and experimental results showed that the analytical model accurately predicted the ultimate bending strengths and min-span deflections of the GFFW panels loaded in four-point bending.