Flexural creep behavior of web reinforced GFRP-balsa sandwich beams: Experimental investigation and modeling

The flexural creep behavior of one-web and two-web reinforced glass fiber reinforced plastic (GFRP)-balsa sandwich beams was studied. Three-point 3000-h bending creep tests with loads of 20%, 40%, 60% and 80% of the beams' ultimate bending capacities were performed. The results show that the specimens exhibit linear viscoelasticity at the 20% and 40% load levels, while creep failure occurs at the 60% and 80% load levels, and the addition of the webs effectively reduces the creep deformation and greatly improves the creep failure time. Moreover, the creep response at the 20% and 40% load levels was successfully fitted by the Findley model and predicted by the general power law. Finally, a method for obtaining the time-dependent modulus of each component of the beams was proposed. On this basis, a model for analyzing the creep deflection of the beams was achieved using first-order shear deformation theory, and the calculated and experimental results matched well.