Bending behaviour of composite sandwich beams manufactured by 3D printing with continuous fibre reinforcement

Abstract

Additive manufacturing with FFF (Fused Filament Fabrication) technology using continuous fibre, allows more complex structure designs with more technical materials than conventional manufacturing processes. The present paper is focused on analysing the bending behaviour of sandwich beams with unidirectional carbon fibre skins and honeycomb type core. The nobelty of the research is focused on printed materials (polyamide 6 reinforced with continuous carbon fibres) and the fact that the core has been manufactured directly in the printig process. The study variable consisted of the spatial arrangement of the beam; for the first type of beams the skins are positioned in parallel with the base plate, whereas for the second type of beams, the skins are placed perpendicullary with respect to the base plate. Thus, in both cases skins are obtained with the same fibre orientation, but with different manufacturing strategies. Otherwise, those configurations where skins are placed in parallel with respect to the base plate, the influence of reinforcing the hexagons of the core with carbon fibres following different strategies has been analysed. On the one hand, the hexagons are reinforced depositing continous carbon fibre following concentric deposition strategy, forming hexagonal rings in each hexagon independently. On the other hand, the overall core is reinforced toghether with continous carbon fibres following the external perimeter of the core. Results show that the beams whose skins have been manufactured in parallel with respect to the base plate have higher stiffness. In the same way, those structures with reinforced cores have a higher stiffnes compared to those with non-reinforced cores.

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