The flexural and compressive properties of sandwich composites with different 3D-printed core structures

In this study, different core structures are produced with polylactic acid (PLA) and carbon fiber reinforced PLA (CFR-PLA) filaments using a 3D printer with fused deposition modeling (FDM) technique. An alternative new core structure is proposed to the honeycomb and square core structures commonly used in the literature. Then, sandwich composites are produced by bonding carbon fiber-epoxy plates to the lower and upper surfaces of these core structures. The effect of carbon fiber reinforcement and core types on the mechanical properties of sandwich composites was investigated. The core structures produced with carbon fiber-reinforced PLA showed lower compressive strength but higher compressive modulus than those produced with pure PLA. Among the core structures, the designed structure showed the highest compressive strength with a value of 9.867 MPa, which is 32.18% and 54.36% higher than the honeycomb and square structure. While the flexural strength and flexural stiffness of the sandwich composites increased with carbon fiber reinforcement, the designed sandwich composite showed approximately 1.40 and 3.15 times the flexural strength of the honeycomb and square sandwich composites, respectively.