Simulation of Mutually Dependent Polymer Flow and Fiber Filled in Polymer Composite Deposition Additive Manufacturing

Short fiber-filled polymers experience increasing applications in melt extrusion additive manufacturing. As the filled polymer is melted and extruded, the fiber-filled polymer suspension exhibits mutually dependent effects, such that flow kinematics influence fiber orientation while the fiber alignment affects the formation of melt flow. This paper presents a fully-coupled numerical scheme to characterize the mutually dependent effects between melt flow and fiber orientation in a non-Newtonian axisymmetric extrusion flow including a free surface using the Galerkin Finite Element Method. The power law fluid model is employed to characterize the shear thinning rheological behaviors of polymer melts. This approach is used to solve the fully-coupled flow velocity and the fiber orientation fields for the nozzle extrusion flow in a large-scale polymer deposition additive manufacturing process. Computed results obtained from both the weakly-coupled and fully-coupled schemes exhibit notable differences in the flow velocity, fiber orientation tensor fields, die swell of free extrudate, and predicted elastic constants.Mechanical Engineerin