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pps proceeding
Symposium: Modeling & Simulation
Oral Presentation
 
 

Thermoforming of polymer laminate films: Thermo-viscoelastic characterization and modeling

Tscharnuter Daniel (1)*, Truszkiewicz Eliza (1), Pilz Gerald (2), Pinter Gerald (2)

(1) Polymer Competence Center Leoben GmbH - Styria - Austria, (2) Montanuniversitaet Leoben - Styria - Austria

Abstract The thermo-viscoelastic behavior of a polymer laminate film was characterized by mechanical measurements to obtain data for material modeling. A quasi-linear viscoelastic model for the simulation of the thermoforming of a polymer film is defined. The model is suitable for large deformations and accounts for non-linear behavior, orthotropy and is temperature-dependent. Objectives The material investigated in this study is a laminate film composed of a blend of polycarbonate and acrylonitrile butadiene styrene (PC-ABS) and polyethylene terephthalate (PET). The PC-ABS and PET films are stretched during manufacture, which introduces anisotropy in the material. For simulations of the thermoforming process it is therefore necessary to characterize the thermo-mechanical properties of the laminate considering the orthotropic symmetry. Computer simulations of the process contribute to an efficient mold- and process design by offering the possibility to conduct studies of the deformation process without the expensive trial-and-error manufacturing of prototype molds. The simulation of the thermoforming process requires detailed material models several reasons: The deformation in the heated state and the fixing of the deformed shape by cooling are determined by the viscoelastic properties of the polymer. Particularly for polymer films, stretching during manufacture can lead to significant orientation of the molecules, giving rise to anisotropic behavior. Non-linear material behavior occurs at large deformations. In this work, we adopt a quasi-linear viscoelastic model to formulate an orthotropic temperature-dependent non-linear viscoelastic model to account for the aforementioned effects to study the thermoforming.