Intrinsic hybrid composite combining in-situ generated form-fit and an innovative interfacial coating

The utilization of continuous fiber reinforced polymers (CFRP) for crash-relevant structural parts is limited due to their low energy absorption capacities [1]. To overcome this lack, a hybrid composite with a ductile aluminum insert, embedded into the surrounding CFRP, is developed based on experimental and simulative investigations [2, 3]. The performance of hybrid composites strongly depends on the connective properties between the individual components. For this reason, form-fit and adhesive bonding is combined within the hybrid composite presented in this study. On one hand, metallic form-fit elements are in-situ generated during the hybridization process and locally pressed into the CFRP [4]. On the other hand, the aluminum is coated by an organically modified silicate (ORMOSIL) layer in order to avoid contact corrosion between the main components of the composite. Additionally this coating is functionalized by silane coupling agents, which results in an improved adhesion to the thermoplastic component. This contribution deals with the adhesion performance and the corrosion prevention of the interfacial zone in dependence on the applied coating and functionalization strategy. In addition to a quasi-static mechanical characterization, the adhesion performance is evaluated at high strain rates using a Split-Hopkinson-Pressure-Bar. A specific sample geometry, which allows for shear loading at high strain rates, has been developed for these experiments. Finally, the effect of combined form-fit and adhesive bonding is evaluated by modified double lap shear specimens, which are manufactured using an innovative manufacturing tool. The results of this study highlight the potential of a combination of different connection types within a hybrid composite