Blome, Thomas (2022)
Thermomechanical Modeling of Amorphous Polymers Through the Glass Transition Region.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00022487
Ph.D. Thesis, Primary publication, Publisher's Version
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Thermomechanical Modeling of Amorphous Polymers Through the Glass Transition Region | ||||
Language: | English | ||||
Referees: | Gruttmann, Prof. Dr. Friedrich ; Müller, Prof. Dr. Ralf | ||||
Date: | 2022 | ||||
Place of Publication: | Darmstadt | ||||
Collation: | xiii, 133, XXXIII Seiten | ||||
Date of oral examination: | 14 September 2022 | ||||
DOI: | 10.26083/tuprints-00022487 | ||||
Abstract: | In this thesis, we propose a novel thermodynamically consistent constitutive framework to model amorphous polymers through the glass transition region based on the internal variables approach. The model assumes the thermorheological simplicity hypothesis and covers different relaxation mechanisms related to bulk, shear, thermal stress and entropy relaxation, which are implemented by means of Prony parameters. Although the model is restricted to sufficiently slow processes, it is capable to span a wide range of temperatures of about ±75 °C around a defined reference temperature and predicts finite deformations up to engineering strain levels of 15 %. A key ingredient is the thermoviscoelastic shift function, which is defined in terms of the polymer’s potential internal energy. This allows to capture a variety of material properties intrinsic to amorphous polymers, such as physical aging and pseudo-yielding in tension and compression. In addition, we provide detailed information on the entire algorithmic solution procedure. The spatial discretization is accomplished using the finite element method, while diagonally implicit Runge-Kutta methods serve as the temporal integrator. Finally, we validate the constitutive model on four different polymeric systems, which comprise one thermoplastic (polyvinyl butyral) and three thermosets. The validation includes dilatometric and calorimetric experiments, tension and compression tests at various temperatures as well as three-point and four-point bending tests of laminated glasses with a polyvinyl butyral interlayer. |
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Status: | Publisher's Version | ||||
URN: | urn:nbn:de:tuda-tuprints-224876 | ||||
Classification DDC: | 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering | ||||
Divisions: | 13 Department of Civil and Environmental Engineering Sciences > Mechanics > Solid Body Mechanics | ||||
Date Deposited: | 13 Oct 2022 12:02 | ||||
Last Modified: | 17 Oct 2022 09:14 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/22487 | ||||
PPN: | 500370311 | ||||
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