  Defects such as voids are observed at multiple length scales of an additively
manufactured composite material. Modeling such defects and their multiscale
interaction is crucial for the materials performance prediction. In this work,
we study as-built defects in fused filament fabricated Polycarbonate/Short
Carbon Fiber (PC/SCF) composite samples. The microscale and mesoscale voids
along with the mesoscale layer orientations have been studied using a
mechanistic reduced-order model. Our result indicates that the microscale
intrabead voids interact with the mesoscale interbead voids and significantly
degrade the mechanical response of the printed composites compared to the
microscale microstructure without voids. The mesoscale layer orientations also
influence the stress-strain response and show better performance when the load
is applied to the bead direction. The efficient reduced-order modeling approach
used in this work provides a way to evaluate multiscale design aspects of
additively manufactured composite materials.
