Design and Additive Manufacture of Architected Short Fiber Reinforced Composites

We present an efficient multiscale design to additive manufacture workflow for architected short fiber reinforced composites, that is, composites with tailored spatially varying, complex arrangement of fibers for improved performance. Our workflow encompasses: (1) multiscale topology optimization (MTO), (2) a unique dehomogenization algorithm, and (3) robotic additive manufacturing. Specifically, we used homogenization based MTO, which enables computationally efficient simultaneous optimization of the macroscale structure and the architected fiber microstructure. We devised a dehomogenization method based on the stripe patterns algorithm to translate the optimized designs into manufacturable print plans, while ensuring minimal deviations, for material extrusion additive manufacturing processes. We adapted this manufacturing approach to process short carbon fiber reinforced epoxy on both 3-DoF (degrees of freedom) Cartesian robots and 6-DoF robotic arms, two widely used robots for additive manufacturing. We demonstrated the workflow's efficacy through design and manufacture of a planar tensile structure and a nonplanar spherical shell, with mechanical tests on the additively manufactured optimized structures agreeing well with numerical predictions.