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@PHDTHESIS{Haler:1025082,
author = {Haßler, Stefan Thomas},
othercontributors = {Behr, Marek and Steinseifer, Ulrich},
title = {{M}odeling and simulation of blood damage in medical
devices},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2026-00517},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2026; Dissertation, Rheinisch-Westfälische
Technische Hochschule Aachen, 2025},
abstract = {Heart failure is the main cause of death in developed
countries. A heart transplantation is not available for most
patients, due to the shortage of donor organs. Ventricular
assist devices (VADs) that support the failing heart for
several years, can be used as a bridge to transplant or even
as a bridge to recovery. However, their development is
complicated, costly and time-consuming, while the
availability of blood samples for in-vitro tests is limited
at the same time. The reliable computational prediction of
blood flow and blood damage within a VAD is a very valuable
tool in the design phase. While the flow prediction with
computational fluid dynamics is well established in
engineering, the prediction of blood damage using
computational hemodynamics is a matter of ongoing
research.This thesis provides a numerically stable approach
to hemolysis prediction for complex domains, that tries to
take the physiological behavior of red blood cells (RBCs)
into account. Here, we follow a three-step-approach: the
blood flow is computed first; then we predict the
deformation of RBCs within that flow field, using the
so-called morphology model; the release of hemoglobin to the
blood plasma is finally predicted by a pore formation model,
based on the RBCs deformation and the flow properties.
Especially the morphology simulation is very challenging,
due to the frequent occurrence of unphysical, negative
eigenvalues in the shape tensor, which lead to diverging
simulations. We apply a logarithmic transformation of the
shape tensor — inspired by the work of Knechtges — that
preserve the positive eigenvalues by design, and derive its
variational multiscale (VMS) stabilized finite element
formulation. The usage of the pore formation model — first
proposed by Vitale et al. — in an Eulerian frame of
reference, is a novelty of this thesis. Furthermore, we
propose to consistently use the multiple reference frames
(MRF) approach for all three simulation steps, for which we
derive the constitutive equations. This allows faster,
steady-state simulations, which result in time-averaged
approximations to the, in principle, transient fields. It
lets us compute the quantities-of-interest directly, like
the pressure head provided by the pump or the averaged
plasma-free hemoglobin content at the outflow, which are
also obtained by experiments.Our model predictions show a
good agreement with experimental results for the FDA’s
benchmark blood pump. Furthermore, we use this modeling
approach to predict the hemocompatibility of a
state-of-the-art centrifugal VAD.},
cin = {416010},
ddc = {620},
cid = {$I:(DE-82)416010_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2026-00517},
url = {https://publications.rwth-aachen.de/record/1025082},
}
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