Functionally graded 3D-printed composite materials with tailorable anisotropy: nozzle oscillation infill pattern

Abstract The performance gains enabled by enhanced microstructural control continue to position additive manufacturing as a technology beyond conventional fabrication techniques. In this work, a novel manufacturing approach is introduced to enhance energy absorption without compromising strength in functionally graded carbon fiber–reinforced composites. By employing oscillatory infill patterns, the method provides a new means of controlling the anisotropy ratio through tailored microstructural orientation of carbon fibers across the composite. This enables the simultaneous achievement of flexibility and high mechanical performance. To demonstrate in-situ stiffness tailoring, functionally graded flexural specimens composed of thermoset epoxy-based carbon fiber composites were fabricated via 3D printing and subjected to mechanical testing. The results indicate an average 10% increase in energy absorption, with no significant reduction in maximum strength. These findings highlight the potential of additive manufacturing to enable spatially controlled stiffness in aerospace structures under bending, reducing the need for additional structural design complexity.