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3D-printed thermoplastic parts with continuous fiber reinforcement are known to offer mechanical performance that is highly dependent on design variables and printing parameters. In this work, the role of the reinforcement distribution on the mechanical response of glass fiber-reinforced thermoplastics printed using the fused filament fabrication (FFF) technique is evaluated. Laminates with alternating and continuous reinforcement architecture as well as different fiber orientations such as isotropic (0°, 90°, and 45°) and concentric configurations are characterized from monotonic tensile and flexural loads. The resulting superior macromechanical performance in terms of higher stiffness and strength achieved in samples reinforced with alternating fiber plies is correlated with the micromechanical fractography characteristics and interlaminar shear capacity. [ABSTRACT FROM AUTHOR]

Additive manufacturing of composite materials is a promising technology. It could solve one of the most critical drawbacks of 3D-printed fiber-reinforced thermoplastics: their low out-of-plane mechanical properties. Due to this factor, it is still unknown how most design and manufacturing parameters affect the out-of-plane properties of composite materials. As a solution, this paper proposes an experimental methodology to characterize out-of-plane printed composite materials. For this purpose, existing standards for traditionally fabricated composites are adapted, investigated, and validated for 3D-printed laminates reinforced with long fibers using the fused filament fabrication technique. Consequently, the methodology is employed to study the impact of stacking sequence and heat treatment conditions on the composites' out-of-plane mechanical properties. The main results showed that increasing the thickness between stacking layers increases the mechanical response due to reducing the number of fiber/matrix interfaces and, consequently, the reduction of porosity. Compared to the initial sample, a heat treatment at 175 °C for 6 h increased the interfacial strength by 101.09% and reduced the porosity in the fiber produced by the additive manufacturing process by 72%. [ABSTRACT FROM AUTHOR]