Fabrication of triangular corrugated structure using 3D printed continuous carbon fiber-reinforced thermosetting epoxy composites

A novel 3D printing methodology using continuous carbon fiber (CCF) reinforced thermosetting epoxy (EP) composites was proposed to fabricate triangular corrugated structures (TCSs). The single-stroke printing path ensured a strong connection between the corrugated core and the face sheets. Silicone rubber was deposited and vulcanized to solve the shape retention problem of the preformed sample during post-curing. Flatwise compression tests were conducted and the evolution of the stress-strain curves upon deformation was discussed as well. Particular attention was paid to the influence of typical parameters, including vacuum pressure and cell length, on the compressive properties of the printed composites. Compared with unreinforced nylon (PA), short fiber-reinforced PA, and continuous fiber-reinforced PA samples, a significant increase in compressive strength, stiffness, and energy absorption abilities was observed for the CCF/EP TCS sample. Finally, 3D printed hexagonal and grid structures, as well as the basic mechanical properties of pure resin and CCF/EP composites, were demonstrated to prove the process capability for the fabrication of high-performance samples with complex geometries. In this respect, the proposed method offers a mold-free and out-of-autoclave approach for thermosetting composites, which is beneficial for their future applications in the lightweight structure industry.