Bending performance of carbon fiber–reinforced polymers/aluminum sandwich structure with different forming process and analysis of failure mode

This paper aims to study the failure response of carbon fiber–reinforced polymers (CFRP)/aluminum honeycomb sandwich structures facing three-point bending test by combining the experiments and numerical models. The theoretical model of three-point bending is established by the finite element software ABAQUS to predict the damage, and then verified by experiments. In order to study the bending performance of sandwich structures made by different forming processes, the test was carried out on sandwich panels with two different molding processes, which are secondary bonding and co-curing. The failure mode and failure mechanism of sandwich structures were also studied by testing specimens with different panel thicknesses and core heights. The results shows that the specimens of the secondary bonding molding process are more prone to damage, most of the samples were observed to be debonded after the test, and the peak load is lower than that of the co-curing. Three different failure modes, closely related to the damage length of the core, which are greatly influenced by different parameters, were observed for the co-cured specimens during the test and parametric studies were carried out for the co-cured specimens. The results showed that small damage length makes it easier to form type I failure mode, while the type II failure mode is more likely to form in situations when the damage length is larger.