Paper Number
PO2                         My Program 

Session
Poster Session

Title
Exploring the interplay of rheological quantities and mechanical properties in 3D-printed lattice structures: A Doehlert design approach

Presentation Date and Time
October 16, 2024 (Wednesday) 6:30

Track / Room
Poster Session / Waterloo 3 & 4

Authors (Click on name to view author profile)

1. Farràs-Tasias, Laia (Ghent University, Department of Materials, Textiles, and Chemical Engineering)
2. Vermeerbergen, Max (Ghent University, Department of Materials, Textiles, and Chemical Engineering)
3. Gilabert Villegas, Francisco Antonio (Ghent University, Department of Materials, Textiles, and Chemical Engineering)
4. Cardon, Ludwig (Ghent University, Department of Materials, Textiles, and Chemical Engineering)
5. Marchesini de Oliveira, Flávio Henrique (Ghent University, Department of Materials, Textiles, and Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Laia Farràs-Tasias, Max Vermeerbergen, Francisco Antonio Gilabert Villegas, Ludwig Cardon and Flávio Henrique Marchesini de Oliveira
Department of Materials, Textiles, and Chemical Engineering, Ghent University, Ghent 9000, Belgium

Speaker / Presenter 
Farràs-Tasias, Laia

Keywords
experimental methods; additve manufacturing; methods; polymer melts; polymers

Text of Abstract
Lattice structures are formed by repeated unit cells arranged in a three-dimensional configuration, resulting in metamaterials with usually higher stiffness and strength compared to conventional structures. These properties make them ideal for lightweight and high mechanical performance applications. Due to their complex geometry, they are often impossible to manufacture with traditional methods, making Additive Manufacturing the preferred technique. Lattice structures are typically manufactured with rigid materials, but there is growing interest in flexible materials for their high damping capability when compressed. When they are produced using technologies like FDM, the rheological properties of the materials during printing significantly influence the mechanical performance of the structure. Issues such as low layer adhesion can lead to anisotropic behavior and affect the failure mechanisms of these structures. During deposition, high shear rates, and temperature variations can occur. For this reason, controlling parameters as viscosity and shear rates becomes crucial. This study focuses on the optimization of the rheological properties of printable materials to enhance lattice structure performance using a Doehlert design of experiments strategy. A challenging flexible lightweight lattice structure manufactured with Thermoplastic Polyurethane is selected to be mechanically improved for a specific application. Flow curves of the material are obtained at different temperatures and the time-temperature superposition principle is employed to obtain viscosity data at a wide range of conditions. Using a combination of Response Surface Methodology with a Doehlert Design, the viscosity and shear of the molten material during extrusion are tuned to find the optimal desired mechanical properties for structure. It is demonstrated that with this method, optimal lattice structures can be printed with minimal number of experiments, overcoming the time-consuming trial-and-error approach widely employed in this field.