3D printed continuous carbon fiber reinforced thermoplastic composite sandwich structure with corrugated core for high stiffness/load capability

In this work, sandwich structure with trapezoidal corrugated cores was 3D printed by fused deposition modeling (FDM) method applying to short and continuous carbon fiber (CF) reinforced nylon filament. The split core of the sandwich structure was designed and fabricated. To investigate the bending characteristics for the sandwich structures, the three-point bending (3 PB) tests were conducted for the different core types. Consequently, it was found that the mechanical behavior and failure modes were significantly changed by core materials and the split number of cores. Also, the dramatic improvements in the mechanical performances (4.1 times higher specific flexural stiffness, 2.6 times larger specific load capability and 8.6 times larger energy absorption capability than those of PET foam core sandwich structure) could be obtained in corrugated sandwich structure which was 3D printed using continuous carbon fiber. This result comes from the precise fiber alignment of continuous carbon fiber along the core, which can be realized only by continuous CF 3D printing technology.