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@PHDTHESIS{Reuvers:1017118,
author = {Reuvers, Marie-Christine},
othercontributors = {Reese, Stefanie and Lion, Alexander},
title = {{M}ultiphysics modeling and experimental analysis of
fiber-reinforced polymers across scales},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-07151},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2025},
abstract = {Nowadays, the growing demand for cost-effective,
customizable, and reusable materials in the domains of
mobility and transport, as well as consumer goods, has led
to an increased significance of fiber-reinforced
thermoplastics (FRTPs). Nonetheless, the industrial
processing of FRTPs in terms of (thermo-)forming processes
is still associated with costly and timeconsuming trial and
error processes to adjust the material design and processing
parameters. Still, oftentimes, unwanted deformations or even
defects in the components arise due to thermal gradients and
residual stresses within the material that need to be
eliminated. In this context, numerical simulation tools,
such as, for example, digital twins (i.e., the virtual
representation of physical objects), can be employed in the
conception and development phase of products and processes
to improve efficiency, shorten development cycles, and
identify potential error sources. In particular, the finite
element method (FEM) has established itself as a suitable
tool for the simulation of complex technical problems due to
steadily increasing computational resources. The accuracy
and reliability of the numerical predictions are, however,
highly dependent on the quality of the employed material
model. Thereby, the material behavior on the structural
level is determined by the underlying microstructure and its
associated characteristics. Especially fiber-reinforced
semi-crystalline polymers (SCPs) represent a challenging
material, due to their complex (time-dependent) inelastic
deformations and dependencies on both the temperature and
the temperature history. Consequently, the internal
structure of FRTPs must be taken into account during model
development by incorporating information across various
scales.Multiscale modeling schemes can provide valuable
insights into the overall constitutive response of the
material. However, these simulations are generally
computationally expensive. In order to reduce the
computational cost and develop frameworks suitable for
industry applications, hierarchical approaches have been
developed and applied. The objective, and simultaneously the
challenge, is to reduce computational costs and experimental
effort while preserving high accuracy and validity across a
broad spectrum of process parameters.The given cumulative
dissertation comprises a collection of journal articles that
contribute to the aforementioned research topics. It aims to
develop a multiphysical framework for fiberreinforced SCPs,
including the impact of temperature and temperature history
across various scales. Starting with the motivation and
corresponding research-relevant questions, followed by an
overview of the current literature.In the first paper, a
thermo-mechanically coupled constitutive model is developed
for semicrystalline polyamide 6 blends. Based on an
extensive experimental data set, comprising mechanical and
thermal tests, a visco-elastic, elasto-plastic approach is
chosen in which nonlinear relaxation, strain hardening, and
a tension-compression asymmetry in yielding are considered.
The degree of crystallinity (DOC) serves as a constant input
parameter, which significantly influences the material
response.Subsequently, a micromechanical and microthermal
analysis is conducted in the second paper, employing the
aforementioned matrix framework accompanied by a detailed
experimental analysis of the composite’s behavior at
various temperatures. Thus, an experimental and virtual data
base is generated for a wide range of process parameters.The
third paper’s objective is to extend the aforementioned
micromechanical matrix model to represent glass-fiber
reinforced polyamide 6 on the macroscale. Therefore,
mechanical and thermal anisotropy is incorporated into the
framework and, subsequently, characterized with the data
base from the second paper. The DOC is now treated as a
non-constant internal variable depending on the temperature
history. Finally, a full 3D thermoforming simulation
isconducted. The validity of the presented approach is
verified by comparison of the numerical material response
with experimental data across all material scales.},
cin = {311510},
ddc = {624},
cid = {$I:(DE-82)311510_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-07151},
url = {https://publications.rwth-aachen.de/record/1017118},
}
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