Flexural Properties of Al/CFRP Multi-layered Hybrid Materials

Abstract

Recently, a sort of super hybrid composite materials made of metal sheets and FRP sheets have attracted a special interest. This report discusses about the flexural properties of the hybrid composite plates in which twenty layers of Al sheets (alminum IN-30, 0.1mm thick) and unidirectional CFRP sheets (fiber volume content 60%, 0.12mm thick) were laminated alternately and symmetrically. The results obtained are summarized as follows: (1) Flexural failure always occurred in the tension side. The reason is assumed to be that the compressive failure mechanism of CFRP layers due to microbackling or shear of carbon fibers changes to the tensile one by the effect of Al sheets which divide the CFRP into many thin layers. (2) On the assumption that the non-linear stress-strain behavior of this hybrid is due to the elastic perfect plastic behavior of aluminum, the theoretical behavior was derived by using the composite beam theory. The results calculated almost agreed with the experimental ones except failure strength. (3) the flexural strength was estimated using the maximum strain criterion for the failure of CFRP lamina. The values estimated were much smaller than those measured. This result suggests that the ultimate strain of CFRP layer in the hybrid composite increases more than that of CFRP monolithic by the effect of Al layers mentioned in (1). (4) The change of repeating stress-strain behavior under a gradually increasing load condition could be simulated accurately. The residual stress after an arbitrary loading could be calculated with a good approximation.