Orientation predictions of fibers within 3D printed strand in material extrusion of polymer composites

A Computational Fluid Dynamics (CFD) model is constructed to predict the fiber orientation within the extruded material in the material extrusion process. The three-dimensional CFD model simulates the deposition of fiber/polymer suspension from the nozzle tip layer by layer on the substrate to print a part. The fiber orientation evolution physics was formulated and implemented in the CFD model allowing for prediction of fiber orientation in deposited extrudate strand during this additive manufacturing process. A parametric analysis for the 3D printed extrudate strand was conducted by changing the following parameters: the gap size, the distance between the nozzle and the substrate, the nozzle head velocity, the shear thinning nature of the suspension, the interaction between fibers and the initial fiber orientations. This simulation model provides detailed information about the material extrusion and fiber orientation evolution in 3D. A correlation between the initial fiber alignment within the nozzle, the gap size, the nozzle width, and the fiber alignment within the printed strand is proposed. The fiber orientation predictions are qualitatively compared with the previous experimental studies. The simulation can be potentially used as slicing software to improve mechanical properties and adhesion between strands during the layup process.