A mechanistic model for tensile property of continuous carbon fiber reinforced plastic composites built by fused filament fabrication

Lightweight and high-strength continuous carbon fiber reinforced plastic (C-CFRP) composites have become promising materials for aerospace, automotive, and sports applications. Recently, fused filament fabrication (FFF) technology enables the production of geometrically complex C-CFRP components that are difficult to fabricate using conventional manufacturing processes. In this study, a novel mechanistic model to predict tensile strength and elastic modulus of C-CFRP parts built by a co-extrusion based FFF process was developed for the first time. The fiber-matrix impregnation behavior, physical gap ratio, and fiber orientation within the as-built C-CFRP were also considered. In order to verify the model, C-CFRP parts were fabricated using different matrix materials including PA, PC, PETG, PLA, and short carbon fiber reinforced PA (SCF/PA) for tensile testing. The comparative results showed that the prediction errors for tensile strength and elastic modulus were less than 5 % and 10 %, respectively. C-CFRP with the matrix of SCF/PA exhibited the largest tensile strength of 288.65 MPa, while C-CFRP with PLA matrix possessed the highest elastic modulus of 29.12 GPa. This study provided an insight into the material-process-impregnation-property relationship during co-extrusion based FFF of C-CFRP components.