Brett G. Compton

3D‐Printing of Lightweight Cellular Composites

A new epoxy-based ink is reported, which enables 3D printing of lightweight cellular composites with controlled alignment of multiscale, high-aspectratio fiber reinforcement to create hierarchical structures inspired by balsa wood. Youngs modulus values up to 10 times higher than existing commercially available 3D-printed polymers are attainable, while comparable strength values are maintained.

Rotational 3D printing of damage-tolerant composites with programmable mechanics

Significance Natural composites exhibit hierarchical and spatially varying structural features that give rise to high stiffness and strength as well as damage tolerance. Here, we report a rotational 3D printing method that enables exquisite control of fiber orientation within engineered composites. Our approach broadens their design, microstructural complexity, and performance space by enabling site-specific optimization of fiber arrangements within short carbon fiber–epoxy composites. Using this approach, we have created composites with programmable strain distribution and failure as well as enhanced damage tolerance. Natural composites exhibit exceptional mechanical performance that often arises from complex fiber arrangements within continuous matrices. Inspired by these natural systems, we developed a rotational 3D printing method that enables spatially controlled orientation of short fibers in polymer matrices solely by varying the nozzle rotation speed relative to the printing speed. Using this method, we fabricated carbon fiber–epoxy composites composed of volume elements (voxels) with programmably defined fiber arrangements, including adjacent regions with orthogonally and helically oriented fibers that lead to nonuniform strain and failure as well as those with purely helical fiber orientations akin to natural composites that exhibit enhanced damage tolerance. Our approach broadens the design, microstructural complexity, and performance space for fiber-reinforced composites through site-specific optimization of their fiber orientation, strain, failure, and damage tolerance.