| Abstract Scope |
Additive manufactured composites offer the potential for tailored stiffness, strength, and geometry flexibility. Printing with continuous carbon fibers may meet certain aerospace components' stiffness and strength requirements. However, the mechanical performance varies with local variations of fiber orientation, void volume, distribution, and layer-to-layer adhesion. Printing parameters and fiber alignment influence performance, while voids formed during manufacturing create stress concentrations, compromising strength and causing unpredictable failures. Void analysis is vital for reliability in these materials. This study characterizes mechanical performance uncertainties in additive-manufactured continuous and short carbon fiber materials. Specimens are divided into continuous and short categories, with further subgroups based on materials: Smooth PA with continuous carbon fiber (CCF), NylonX, and PLA-CF with short carbon fiber (SCF). For CCF, four stacking sequences ([04]S, [+/-454]S, [904]S, [0|+45|-45|90]S) are explored with five specimens each, as are the SCF materials. Optimal specimen geometry is determined through FEA to ensure precise fracture at the gauge section. The experimental assay included tensile testing, followed by fracture surface and void distribution characterization high-resolution CT scanning with a Bruker SkyScan 1272. The uncertainties in stiffness and strength are quantified and correlated to the specimen location on the print bed and the stacking sequence. |