Abstract: This paper presents the experimental research on the flexural performance of sandwich beams with high different foam core densities. First, five foam cores with different densities are explored (48~413 kg/m³) using three point bending tests. Test results show that, when the foam core density is less than 199 kg/m³, the ultimate bending strength of the sandwich beams increase with the core density increase, but when the core density is greater than or equal to 199 kg/m³, the ultimate bending strength of sandwich beams tends to a fixed value. The failure mode of the composite beams changed from core indentation failure to face compressive failure as the core densities increase. Second, high-order theory based on variational principle was used to analyze the deflection and the strain distribution of the sandwich beams. Finally, analysis of the ultimate bending strength of the sandwich beams was conducted.

Key words: composite, sandwich beam, foam core, density, bending, failure load, VARTM