Authors:

Ludvik Mathis Fjeld

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About Paper:

Carbon fiber polymer-matrix composite materials have become crucial for fabricating structural parts and molds across various applications and industries. Extrusion deposition additive manufacturing (EDAM) systems have introduced 3D printing abilities with these materials. Due to the shear-thinning nature of flows in these systems, rheological properties like viscosity change with shear rates. These variations can impact the mechanical properties of the printed pieces, which motivates this study. To describe these effects, Newtonian (Hagen-Poiseuille) and non-Newtonian viscosity models (Power law and Carreau) are applied to a fully developed pipe flow in the cylindrical nozzle of the EDAM system, examining its transient response to pressure and flow rate changes. A constrained, nonlinear optimization tool is employed in MATLAB to characterize the behavior of the material throughout the print. This approach is validated through a representative geometry printed at the Composites Additive Manufacturing Research Interface (CAMRI) with varying printing speeds that subject the flow to different shear rates. Future work includes developing a model that accounts for melt temperature and thermal history for more accurate viscosity predictions. Keywords: Composites; Additive Manufacturing; Rheology

Source:

Purdue University / 2024

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Co-authors:

Ludvik Mathis Fjeld