---
_id: '64251'
abstract:
- lang: eng
text: "ABSTRACT\r\n Clinching
is a widely adopted joining technique in the automotive industry, enabling the
fabrication of lightweight structures from dissimilar sheet materials. Accurate
prediction of the fatigue life of clinched joints is essential for ensuring structural
safety and minimizing development costs. However, full 3D fatigue simulations
over millions of cycles are computationally intensive due to the complexity of
contact mechanics. This study introduces a 2D numerical model that circumvents
direct contact modeling by applying a slip condition at the sheet interface, significantly
reducing computational demands. A micro‐slip friction model is used to represent
the mechanical interface behavior, while a two‐scale damage model captures the
fatigue damage evolution. The model is validated against experimental data and
used to investigate the influence of friction coefficient and tangential contact
stiffness on fatigue life, highlighting its efficiency and predictive capability."
article_number: e70035
author:
- first_name: Chin
full_name: Chen, Chin
id: '114741'
last_name: Chen
- first_name: Martin
full_name: Hofmann, Martin
last_name: Hofmann
- first_name: Thomas
full_name: Wallmersperger, Thomas
last_name: Wallmersperger
citation:
ama: Chen C, Hofmann M, Wallmersperger T. A 2D Approach to Predict the High‐Cycle
Fatigue Life of Clinched Joints. PAMM. 2026;26(1). doi:10.1002/pamm.70035
apa: Chen, C., Hofmann, M., & Wallmersperger, T. (2026). A 2D Approach to Predict
the High‐Cycle Fatigue Life of Clinched Joints. PAMM, 26(1), Article
e70035. https://doi.org/10.1002/pamm.70035
bibtex: '@article{Chen_Hofmann_Wallmersperger_2026, title={A 2D Approach to Predict
the High‐Cycle Fatigue Life of Clinched Joints}, volume={26}, DOI={10.1002/pamm.70035},
number={1e70035}, journal={PAMM}, publisher={Wiley}, author={Chen, Chin and Hofmann,
Martin and Wallmersperger, Thomas}, year={2026} }'
chicago: Chen, Chin, Martin Hofmann, and Thomas Wallmersperger. “A 2D Approach to
Predict the High‐Cycle Fatigue Life of Clinched Joints.” PAMM 26, no. 1
(2026). https://doi.org/10.1002/pamm.70035.
ieee: 'C. Chen, M. Hofmann, and T. Wallmersperger, “A 2D Approach to Predict the
High‐Cycle Fatigue Life of Clinched Joints,” PAMM, vol. 26, no. 1, Art.
no. e70035, 2026, doi: 10.1002/pamm.70035.'
mla: Chen, Chin, et al. “A 2D Approach to Predict the High‐Cycle Fatigue Life of
Clinched Joints.” PAMM, vol. 26, no. 1, e70035, Wiley, 2026, doi:10.1002/pamm.70035.
short: C. Chen, M. Hofmann, T. Wallmersperger, PAMM 26 (2026).
date_created: 2026-02-19T10:03:06Z
date_updated: 2026-02-24T15:10:04Z
doi: 10.1002/pamm.70035
intvolume: ' 26'
issue: '1'
language:
- iso: eng
project:
- _id: '142'
name: TRR 285 - Subproject B03
- _id: '130'
name: 'TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
Prozessketten'
- _id: '132'
name: TRR 285 - Project Area B
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: A 2D Approach to Predict the High‐Cycle Fatigue Life of Clinched Joints
type: journal_article
user_id: '114741'
volume: 26
year: '2026'
...
---
_id: '65266'
abstract:
- lang: eng
text: "ABSTRACT\r\n This work
is concerned with the modeling of a cold‐box sand, a composition of sand grains
and a resin binder. To this end, experiments are performed, which show the following
characteristics: localization phenomena in the form of a shear band, softening
behavior in the force‐displacement curve, and asymmetric behavior for compression
and tension. To model this complex material behavior, a micromorphic continuum
is used. In the present contribution, we focus on the linear‐elastic regime and
demonstrate the identifiability of micromorphic material parameters under deliberately
induced inhomogeneous deformation states. In addition to the degrees of freedom
of a classical continuum, the micromorphic model has additional degrees of freedom,
introduced here in a phenomenological sense to represent kinematically enriched
deformation modes associated with the granular microstructure. Accordingly, the
micromorphic fields are not interpreted as a separate physical scale (e.g., “binder”
vs. “grains”), but as an effective continuum description at the specimen scale.
This contribution addresses parameter identification for a micromorphic model
of cold‐box sand, with a clear separation between homogeneous deformation states
governing classical elastic parameters and inhomogeneous states required to activate
and identify micromorphic length‐scale parameters. The main challenge lies in
identifying the micro material parameters. To determine these, the corresponding
gradient terms in the constitutive formulation must be triggered via properly
tuned experiments. Micro‐parameter identification is demonstrated using synthetic
data generated from a boundary‐value problem with inhomogeneous displacement fields.
The chosen benchmark enables controlled activation of gradient terms and thereby
renders optimization‐based identification of micromorphic parameters feasible.
The synthetic example is deliberately chosen to assess feasibility and identifiability
under controlled conditions, thereby isolating micromorphic identifiability aspects
from experimental uncertainties. The novelty of the contribution lies in explicitly
linking micromorphic parameter identifiability to kinematic inhomogeneity, and
in demonstrating this link within a tractable forward– inverse setting for a linear‐elastic
micromorphic continuum."
article_number: e70093
author:
- first_name: Alexander
full_name: Börger, Alexander
id: '52037'
last_name: Börger
- first_name: Rolf
full_name: Mahnken, Rolf
last_name: Mahnken
- first_name: Ismail
full_name: Caylak, Ismail
id: '75'
last_name: Caylak
- first_name: Richard
full_name: Ostwald, Richard
id: '106876'
last_name: Ostwald
orcid: 0000-0003-2147-8444
citation:
ama: Börger A, Mahnken R, Caylak I, Ostwald R. Aspects of Parameter Identification
for a Micromorphic Continuum applied to a Cold‐Box Sand. Proceedings in Applied
Mathematics and Mechanics. 2026;26(2). doi:10.1002/pamm.70093
apa: Börger, A., Mahnken, R., Caylak, I., & Ostwald, R. (2026). Aspects of Parameter
Identification for a Micromorphic Continuum applied to a Cold‐Box Sand. Proceedings
in Applied Mathematics and Mechanics, 26(2), Article e70093. https://doi.org/10.1002/pamm.70093
bibtex: '@article{Börger_Mahnken_Caylak_Ostwald_2026, title={Aspects of Parameter
Identification for a Micromorphic Continuum applied to a Cold‐Box Sand}, volume={26},
DOI={10.1002/pamm.70093}, number={2e70093},
journal={Proceedings in Applied Mathematics and Mechanics}, publisher={Wiley},
author={Börger, Alexander and Mahnken, Rolf and Caylak, Ismail and Ostwald, Richard},
year={2026} }'
chicago: Börger, Alexander, Rolf Mahnken, Ismail Caylak, and Richard Ostwald. “Aspects
of Parameter Identification for a Micromorphic Continuum Applied to a Cold‐Box
Sand.” Proceedings in Applied Mathematics and Mechanics 26, no. 2 (2026).
https://doi.org/10.1002/pamm.70093.
ieee: 'A. Börger, R. Mahnken, I. Caylak, and R. Ostwald, “Aspects of Parameter Identification
for a Micromorphic Continuum applied to a Cold‐Box Sand,” Proceedings in Applied
Mathematics and Mechanics, vol. 26, no. 2, Art. no. e70093, 2026, doi: 10.1002/pamm.70093.'
mla: Börger, Alexander, et al. “Aspects of Parameter Identification for a Micromorphic
Continuum Applied to a Cold‐Box Sand.” Proceedings in Applied Mathematics and
Mechanics, vol. 26, no. 2, e70093, Wiley, 2026, doi:10.1002/pamm.70093.
short: A. Börger, R. Mahnken, I. Caylak, R. Ostwald, Proceedings in Applied Mathematics
and Mechanics 26 (2026).
date_created: 2026-04-01T04:52:34Z
date_updated: 2026-04-01T04:54:17Z
department:
- _id: '9'
- _id: '952'
- _id: '321'
doi: 10.1002/pamm.70093
intvolume: ' 26'
issue: '2'
language:
- iso: eng
publication: Proceedings in Applied Mathematics and Mechanics
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Aspects of Parameter Identification for a Micromorphic Continuum applied to
a Cold‐Box Sand
type: journal_article
user_id: '85414'
volume: 26
year: '2026'
...
---
_id: '59740'
abstract:
- lang: eng
text: ABSTRACTIn this contribution, we propose
an innovative method for determining optimal control sequences for nonlinear systems
with partially unknown dynamics, which further expands our previous work. Within
the paradigm of model‐based design, the practicality and safety of commissioning
feedforward controls and feedback controllers have priority. Our approach leverages
probabilistic Gaussian processes to adjust for model inaccuracies from measured
system data. This differs from conventional approaches that involve complicated
analytical modeling and may entail a substantial time investment to acquire expertise
and may prove impractical. Consequently, we address the limitations inherent in
traditional design methodologies. Our research focuses on the formulation and
solution of the hybrid1 optimal control problem using probabilistic
state predictions and multiple shooting. This ensures adaptability, data efficiency,
and resilience against uncertainties in system dynamics. These attributes are
empirically substantiated through experimental validation on a chaotic and highly
sensitive dynamical system—a double pendulum on a cart. Our methodology unfolds
as an iterative learning process, systematically exploring diverse controls, accumulating
data within each iteration, and refining the control strategy until the desired
task is accomplished. The adoption of the two‐degree‐of‐freedom control structure
allows for the distinct consideration of the feedforward and the feedback control
signal. For the latter, we employ a time‐variant, linear quadratic regulator (LQR)
designed to stabilize the system around its target trajectory. Furthermore, we
integrate a probabilistic long‐term prediction through the unscented transform,
enabling systematic anticipation of safety‐critical violations. Detailed insights
into relevant implementation aspects are provided. To ascertain the real‐world
applicability, we present an exemplary application involving a double pendulum
on a cart. The objective is to bring the pendulum arms from the lower stable to
the upper unstable equilibrium by horizontally moving the cart and subsequently
stabilize them. In this scenario, we assume that the centrifugal forces, crucial
to the system dynamics, have not been accurately modeled and must be learned from
data. Solving the control task took only 5 iterations and 1 h of computation time,
which surpasses our previous work [2], where we used the purely data‐driven PILCO
framework and required 27 iterations and 57 h of computation time. The time of
interaction with the system decreased by and the computation time is lowered
by . It demonstrates significant practical applicability for commissioning control systems.
author:
- first_name: Michael
full_name: Hesse, Michael
id: '29222'
last_name: Hesse
- first_name: Luis
full_name: Schwarzer, Luis
last_name: Schwarzer
- first_name: Julia
full_name: Timmermann, Julia
id: '15402'
last_name: Timmermann
- first_name: Ansgar
full_name: Trächtler, Ansgar
id: '552'
last_name: Trächtler
citation:
ama: Hesse M, Schwarzer L, Timmermann J, Trächtler A. Robust and Efficient Hybrid
Optimal Control via Gaussian Process Regression and Multiple Shooting With Experimental
Validation on a Double Pendulum on a Cart. PAMM. 2025;25(2). doi:10.1002/pamm.70004
apa: Hesse, M., Schwarzer, L., Timmermann, J., & Trächtler, A. (2025). Robust
and Efficient Hybrid Optimal Control via Gaussian Process Regression and Multiple
Shooting With Experimental Validation on a Double Pendulum on a Cart. PAMM,
25(2). https://doi.org/10.1002/pamm.70004
bibtex: '@article{Hesse_Schwarzer_Timmermann_Trächtler_2025, title={Robust and Efficient
Hybrid Optimal Control via Gaussian Process Regression and Multiple Shooting With
Experimental Validation on a Double Pendulum on a Cart}, volume={25}, DOI={10.1002/pamm.70004}, number={2},
journal={PAMM}, publisher={Wiley}, author={Hesse, Michael and Schwarzer, Luis
and Timmermann, Julia and Trächtler, Ansgar}, year={2025} }'
chicago: Hesse, Michael, Luis Schwarzer, Julia Timmermann, and Ansgar Trächtler.
“Robust and Efficient Hybrid Optimal Control via Gaussian Process Regression and
Multiple Shooting With Experimental Validation on a Double Pendulum on a Cart.”
PAMM 25, no. 2 (2025). https://doi.org/10.1002/pamm.70004.
ieee: 'M. Hesse, L. Schwarzer, J. Timmermann, and A. Trächtler, “Robust and Efficient
Hybrid Optimal Control via Gaussian Process Regression and Multiple Shooting With
Experimental Validation on a Double Pendulum on a Cart,” PAMM, vol. 25,
no. 2, 2025, doi: 10.1002/pamm.70004.'
mla: Hesse, Michael, et al. “Robust and Efficient Hybrid Optimal Control via Gaussian
Process Regression and Multiple Shooting With Experimental Validation on a Double
Pendulum on a Cart.” PAMM, vol. 25, no. 2, Wiley, 2025, doi:10.1002/pamm.70004.
short: M. Hesse, L. Schwarzer, J. Timmermann, A. Trächtler, PAMM 25 (2025).
date_created: 2025-04-30T08:18:46Z
date_updated: 2025-09-03T10:35:24Z
department:
- _id: '880'
- _id: '153'
doi: 10.1002/pamm.70004
intvolume: ' 25'
issue: '2'
language:
- iso: eng
project:
- _id: '690'
name: 'DART: Datengetriebene Methoden in der Regelungstechnik'
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: Robust and Efficient Hybrid Optimal Control via Gaussian Process Regression
and Multiple Shooting With Experimental Validation on a Double Pendulum on a Cart
type: journal_article
user_id: '15402'
volume: 25
year: '2025'
...
---
_id: '52217'
abstract:
- lang: eng
text: AbstractPolycarbonate (PC) is an amorphous
polymer that is an extremely robust material with a high tenacity, and thus suitable
for a lightweight construction with glass‐like transparency. Due to these advantageous
properties, PC is often used in industry for example in medical devices, automotive
headlamps, sporting equipment, electronics, and a variety of other products. PC
is often subjected to uniaxial and biaxial loading conditions. Therefore, reliable
material models have to take into account the various resulting experimental effects.
For those reasons, we investigate PC specimens under uniaxial and biaxial loading
by using different stretch rates and loading scenarios. In addition to that, we
propose methods for optical measurement of local stretches to obtain the approximated
local true stress. In future work, the displacement fields and the resulting reaction
forces will be used for parameter identification of constitutive equations.
author:
- first_name: Ayoub
full_name: Hamdoun, Ayoub
last_name: Hamdoun
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Hamdoun A, Mahnken R. Experimental investigations of uniaxial and biaxial cold
stretching within PC‐films and bars using optical measurements. PAMM. Published
online 2024. doi:10.1002/pamm.202300114
apa: Hamdoun, A., & Mahnken, R. (2024). Experimental investigations of uniaxial
and biaxial cold stretching within PC‐films and bars using optical measurements.
PAMM. https://doi.org/10.1002/pamm.202300114
bibtex: '@article{Hamdoun_Mahnken_2024, title={Experimental investigations of uniaxial
and biaxial cold stretching within PC‐films and bars using optical measurements},
DOI={10.1002/pamm.202300114},
journal={PAMM}, publisher={Wiley}, author={Hamdoun, Ayoub and Mahnken, Rolf},
year={2024} }'
chicago: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial
and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.”
PAMM, 2024. https://doi.org/10.1002/pamm.202300114.
ieee: 'A. Hamdoun and R. Mahnken, “Experimental investigations of uniaxial and biaxial
cold stretching within PC‐films and bars using optical measurements,” PAMM,
2024, doi: 10.1002/pamm.202300114.'
mla: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial
and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.”
PAMM, Wiley, 2024, doi:10.1002/pamm.202300114.
short: A. Hamdoun, R. Mahnken, PAMM (2024).
date_created: 2024-02-29T13:53:13Z
date_updated: 2024-02-29T13:58:38Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202300114
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Experimental investigations of uniaxial and biaxial cold stretching within
PC‐films and bars using optical measurements
type: journal_article
user_id: '335'
year: '2024'
...
---
_id: '56212'
abstract:
- lang: eng
text: AbstractTo increase the quality of computational
results for heterogeneous materials like fiber‐reinforced composites with Prandtl–Reuss‐type
material laws, goal‐oriented measures of the adaptive finite element method coupled
to model adaptivity is established. The former is an adaptive mesh refinement
on the macroscale, which allows to control the spatial discretization errors.
The latter is an efficient combination of a numerically low cost nonuniform transformation
field analysis (NTFA) and numerically high cost full‐field elasto‐plastic homogenization
methods on the microscale. The present contribution deals with the application
of the concept of downwind and upwind approximations to a goal‐oriented a posteriori
error estimator based on duality techniques by means of reduced order homogenization
schemes like NTFA, and with accuracy and numerical efficiency of the proposed
goal‐oriented adaptive framework. NTFA consists of an offline phase and an online
phase. During the offline phase, some relevant information of the micro system
under consideration is precomputed allowing a reduced set of equations to be solved
in the online phase. Thus, NTFA leads to a quite efficient homogenization method
but less accurate compared to the full‐field homogenization method which is characterized
with a high computational demand for accounting nonlinear microstructural mechanisms.
Due to nonlinearities and time‐dependency of plasticity, the estimation of error
transport and error generation are obtained with a backward‐in‐time dual method
despite a high demand on memory capacity. In this contribution, the dual problem
is solved with a forward‐in‐time dual method that allows estimating the full error
during the resolution of the primal problem without the need for extra memory
capacity. Several numerical examples illustrate the effectiveness of the proposed
adaptive approach based on downwind and upwind approximations.
author:
- first_name: Arnold
full_name: Tchomgue Simeu, Arnold
id: '83075'
last_name: Tchomgue Simeu
- first_name: Rolf
full_name: Mahnken, Rolf
last_name: Mahnken
citation:
ama: Tchomgue Simeu A, Mahnken R. Mesh‐ and model adaptivity for NTFA and full‐field
elasto‐plastic homogenization based on downwind and upwind approximations. PAMM.
Published online 2024. doi:10.1002/pamm.202400074
apa: Tchomgue Simeu, A., & Mahnken, R. (2024). Mesh‐ and model adaptivity for
NTFA and full‐field elasto‐plastic homogenization based on downwind and upwind
approximations. PAMM. https://doi.org/10.1002/pamm.202400074
bibtex: '@article{Tchomgue Simeu_Mahnken_2024, title={Mesh‐ and model adaptivity
for NTFA and full‐field elasto‐plastic homogenization based on downwind and upwind
approximations}, DOI={10.1002/pamm.202400074},
journal={PAMM}, publisher={Wiley}, author={Tchomgue Simeu, Arnold and Mahnken,
Rolf}, year={2024} }'
chicago: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Mesh‐ and Model Adaptivity for
NTFA and Full‐field Elasto‐plastic Homogenization Based on Downwind and Upwind
Approximations.” PAMM, 2024. https://doi.org/10.1002/pamm.202400074.
ieee: 'A. Tchomgue Simeu and R. Mahnken, “Mesh‐ and model adaptivity for NTFA and
full‐field elasto‐plastic homogenization based on downwind and upwind approximations,”
PAMM, 2024, doi: 10.1002/pamm.202400074.'
mla: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Mesh‐ and Model Adaptivity for NTFA
and Full‐field Elasto‐plastic Homogenization Based on Downwind and Upwind Approximations.”
PAMM, Wiley, 2024, doi:10.1002/pamm.202400074.
short: A. Tchomgue Simeu, R. Mahnken, PAMM (2024).
date_created: 2024-09-23T11:23:21Z
date_updated: 2024-09-23T11:26:52Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202400074
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Mesh‐ and model adaptivity for NTFA and full‐field elasto‐plastic homogenization
based on downwind and upwind approximations
type: journal_article
user_id: '85414'
year: '2024'
...
---
_id: '54281'
abstract:
- lang: eng
text: AbstractPolycarbonate (PC) is an amorphous
polymer that is an extremely robust material with a high tenacity, and thus suitable
for a lightweight construction with glass‐like transparency. Due to these advantageous
properties, PC is often used in industry for example in medical devices, automotive
headlamps, sporting equipment, electronics, and a variety of other products. PC
is often subjected to uniaxial and biaxial loading conditions. Therefore, reliable
material models have to take into account the various resulting experimental effects.
For those reasons, we investigate PC specimens under uniaxial and biaxial loading
by using different stretch rates and loading scenarios. In addition to that, we
propose methods for optical measurement of local stretches to obtain the approximated
local true stress. In future work, the displacement fields and the resulting reaction
forces will be used for parameter identification of constitutive equations.
author:
- first_name: Ayoub
full_name: Hamdoun, Ayoub
id: '57708'
last_name: Hamdoun
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Hamdoun A, Mahnken R. Experimental investigations of uniaxial and biaxial cold
stretching within PC‐films and bars using optical measurements. PAMM. Published
online 2024. doi:10.1002/pamm.202300114
apa: Hamdoun, A., & Mahnken, R. (2024). Experimental investigations of uniaxial
and biaxial cold stretching within PC‐films and bars using optical measurements.
PAMM. https://doi.org/10.1002/pamm.202300114
bibtex: '@article{Hamdoun_Mahnken_2024, title={Experimental investigations of uniaxial
and biaxial cold stretching within PC‐films and bars using optical measurements},
DOI={10.1002/pamm.202300114},
journal={PAMM}, publisher={Wiley}, author={Hamdoun, Ayoub and Mahnken, Rolf},
year={2024} }'
chicago: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial
and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.”
PAMM, 2024. https://doi.org/10.1002/pamm.202300114.
ieee: 'A. Hamdoun and R. Mahnken, “Experimental investigations of uniaxial and biaxial
cold stretching within PC‐films and bars using optical measurements,” PAMM,
2024, doi: 10.1002/pamm.202300114.'
mla: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial
and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.”
PAMM, Wiley, 2024, doi:10.1002/pamm.202300114.
short: A. Hamdoun, R. Mahnken, PAMM (2024).
date_created: 2024-05-14T09:06:26Z
date_updated: 2024-09-26T11:25:10Z
department:
- _id: '9'
- _id: '154'
doi: 10.1002/pamm.202300114
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: Experimental investigations of uniaxial and biaxial cold stretching within
PC‐films and bars using optical measurements
type: journal_article
user_id: '57708'
year: '2024'
...
---
_id: '61412'
abstract:
- lang: eng
text: 'AbstractMechanical clinching is a frequently
used joining method for technical components. These joints are usually weak spots.
Here, corrosion and fatigue are decisive influencing factors for the assessment
of the service life of such joints. Corrosion generally leads to material deterioration
and thus to premature failure of the joints. Under certain circumstances, however,
corrosion can lead to an increased fatigue life. While this effect has not yet
been fully understood, the present work provides a possible explanation and a
modeling approach to predict the fatigue life of precorroded clinched joints.
The increased fatigue life is observed when the clinched components are briefly
(up to 3 weeks) exposed to a salt spray environment. During this time, a small
layer of corrosion products protrudes from the metal surface and fills the gaps
between the joined sheets. Due to the increased contact area, the mechanical stress
in the joint decreases, resulting in an improved fatigue performance. Although
there are a variety of corrosion phenomena, for example, pitting, intergranular,
and transgranular corrosion as well as galvanic corrosion, experimental studies
indicate that galvanic corrosion is the main contributor of this effect. In the
present work, a coupled electro‐chemo‐mechanical corrosion model is presented
and applied to two test cases. Case I: corrosion products growth, and Case II:
corrosion products growth and mechanical loading.'
article_number: e202400028
author:
- first_name: Sven
full_name: Harzheim, Sven
last_name: Harzheim
- first_name: Chin
full_name: Chen, Chin
id: '114741'
last_name: Chen
- first_name: Martin
full_name: Hofmann, Martin
last_name: Hofmann
- first_name: Thomas
full_name: Wallmersperger, Thomas
last_name: Wallmersperger
citation:
ama: Harzheim S, Chen C, Hofmann M, Wallmersperger T. Coupled chemo‐electro‐mechanical
model for galvanic corrosion in clinched components. PAMM. 2024;24(4).
doi:10.1002/pamm.202400028
apa: Harzheim, S., Chen, C., Hofmann, M., & Wallmersperger, T. (2024). Coupled
chemo‐electro‐mechanical model for galvanic corrosion in clinched components.
PAMM, 24(4), Article e202400028. https://doi.org/10.1002/pamm.202400028
bibtex: '@article{Harzheim_Chen_Hofmann_Wallmersperger_2024, title={Coupled chemo‐electro‐mechanical
model for galvanic corrosion in clinched components}, volume={24}, DOI={10.1002/pamm.202400028},
number={4e202400028}, journal={PAMM}, publisher={Wiley}, author={Harzheim, Sven
and Chen, Chin and Hofmann, Martin and Wallmersperger, Thomas}, year={2024} }'
chicago: Harzheim, Sven, Chin Chen, Martin Hofmann, and Thomas Wallmersperger. “Coupled
Chemo‐electro‐mechanical Model for Galvanic Corrosion in Clinched Components.”
PAMM 24, no. 4 (2024). https://doi.org/10.1002/pamm.202400028.
ieee: 'S. Harzheim, C. Chen, M. Hofmann, and T. Wallmersperger, “Coupled chemo‐electro‐mechanical
model for galvanic corrosion in clinched components,” PAMM, vol. 24, no.
4, Art. no. e202400028, 2024, doi: 10.1002/pamm.202400028.'
mla: Harzheim, Sven, et al. “Coupled Chemo‐electro‐mechanical Model for Galvanic
Corrosion in Clinched Components.” PAMM, vol. 24, no. 4, e202400028, Wiley,
2024, doi:10.1002/pamm.202400028.
short: S. Harzheim, C. Chen, M. Hofmann, T. Wallmersperger, PAMM 24 (2024).
date_created: 2025-09-23T11:58:43Z
date_updated: 2026-02-24T15:12:47Z
doi: 10.1002/pamm.202400028
intvolume: ' 24'
issue: '4'
language:
- iso: eng
project:
- _id: '132'
name: TRR 285 - Project Area B
- _id: '142'
name: TRR 285 - Subproject B03
- _id: '130'
name: 'TRR 285: Methodenentwicklung zur mechanischen Fügbarkeit in wandlungsfähigen
Prozessketten'
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: Coupled chemo‐electro‐mechanical model for galvanic corrosion in clinched components
type: journal_article
user_id: '114741'
volume: 24
year: '2024'
...
---
_id: '60359'
abstract:
- lang: eng
text: AbstractThe free‐surface lattice Boltzmann
method uses a volume of fluid approach to simulate immiscible two‐fluid flow problems.
It divides the simulation domain into three distinct phases—gas, fluid, and interface—where
computation within the gas phase is disregarded. The interface delineates a one‐cell‐thick
layer between the first two phases, validated physically for implementation in
the HPC C++ multiphysics framework waLBerla but lacking an
exhaustive performance analysis. This paper aims to shed light on node‐level performance
on different architectures, employing continuous benchmarking, showing and analyzing
weak scaling results on a modern HPC cluster, the Fritz supercomputer, and reporting
energy consumption for the current implementation.
author:
- first_name: Jonas
full_name: Plewinski, Jonas
last_name: Plewinski
- first_name: Christoph
full_name: Alt, Christoph
id: '100625'
last_name: Alt
- first_name: Harald
full_name: Köstler, Harald
last_name: Köstler
- first_name: Ulrich
full_name: Rüde, Ulrich
last_name: Rüde
citation:
ama: 'Plewinski J, Alt C, Köstler H, Rüde U. Performance analysis of the free surface
lattice Boltzmann implementation in waLBerla. In: PAMM. Vol 24. Wiley;
2024. doi:10.1002/pamm.202400196'
apa: Plewinski, J., Alt, C., Köstler, H., & Rüde, U. (2024). Performance analysis
of the free surface lattice Boltzmann implementation in waLBerla. PAMM,
24(3). https://doi.org/10.1002/pamm.202400196
bibtex: '@inproceedings{Plewinski_Alt_Köstler_Rüde_2024, title={Performance analysis
of the free surface lattice Boltzmann implementation in waLBerla}, volume={24},
DOI={10.1002/pamm.202400196},
number={3}, booktitle={PAMM}, publisher={Wiley}, author={Plewinski, Jonas and
Alt, Christoph and Köstler, Harald and Rüde, Ulrich}, year={2024} }'
chicago: Plewinski, Jonas, Christoph Alt, Harald Köstler, and Ulrich Rüde. “Performance
Analysis of the Free Surface Lattice Boltzmann Implementation in WaLBerla.” In
PAMM, Vol. 24. Wiley, 2024. https://doi.org/10.1002/pamm.202400196.
ieee: 'J. Plewinski, C. Alt, H. Köstler, and U. Rüde, “Performance analysis of the
free surface lattice Boltzmann implementation in waLBerla,” in PAMM, 2024,
vol. 24, no. 3, doi: 10.1002/pamm.202400196.'
mla: Plewinski, Jonas, et al. “Performance Analysis of the Free Surface Lattice
Boltzmann Implementation in WaLBerla.” PAMM, vol. 24, no. 3, Wiley, 2024,
doi:10.1002/pamm.202400196.
short: 'J. Plewinski, C. Alt, H. Köstler, U. Rüde, in: PAMM, Wiley, 2024.'
date_created: 2025-06-24T14:01:15Z
date_updated: 2025-06-24T14:04:05Z
doi: 10.1002/pamm.202400196
intvolume: ' 24'
issue: '3'
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: Performance analysis of the free surface lattice Boltzmann implementation in
waLBerla
type: conference
user_id: '100625'
volume: 24
year: '2024'
...
---
_id: '57893'
abstract:
- lang: eng
text: AbstractControl engineering applications
usually require a model that accurately represents the dynamics of the system.
In addition to classical physical modeling, powerful data‐driven approaches are
gaining popularity. However, the resulting models may not be ideal for control
design due to their black‐box structure, which inherently limits interpretability.
Formulating the system dynamics in port‐Hamiltonian form is highly beneficial,
as its valuable property of passivity enables the straightforward design of globally
stable controllers while ensuring physical interpretability. In a recently published
article, we presented a method for data‐driven inference of port‐Hamiltonian models
for complex mechatronic systems, requiring only fundamental physical prior knowledge.
The resulting models accurately represent the nonlinear dynamics of the considered
systems and are physically interpretable. In this contribution, we advance our
previous work by including two key elements. Firstly, we demonstrate the application
of the above described data‐driven PCHD models for controller design. Preserving
the port‐Hamiltonian form in the closed loop not only guarantees global stability
and robustness but also ensures desired speed and damping characteristics. Since
control systems based on output measurements, which are continuously measured
during operation due to the feedback structure, we secondly aim to use this data.
Thus, we augment the existing modeling strategy with an intelligent adaptation
approach to address uncertainties and (un)predictable system changes in mechatronic
systems throughout their lifecycle, such as the installation of new components,
wear, or temperature fluctuations during operation. Our proposed algorithm for
recursively calculated data‐driven port‐Hamiltonian models utilizes a least‐squares
approach with extensions such as automatically adjusting the forgetting factor
and controlling the covariance matrix trace. We demonstrate the results through
model‐based application on an academic example and experimental validation on
a test bench.
author:
- first_name: Annika
full_name: Junker, Annika
id: '41470'
last_name: Junker
orcid: 0009-0002-6475-2503
- first_name: Julia
full_name: Timmermann, Julia
id: '15402'
last_name: Timmermann
- first_name: Ansgar
full_name: Trächtler, Ansgar
id: '552'
last_name: Trächtler
citation:
ama: Junker A, Timmermann J, Trächtler A. Adaptive Data‐Driven Models in Port‐Hamiltonian
Form for Control Design. PAMM. 2024;25(1). doi:10.1002/pamm.202400154
apa: Junker, A., Timmermann, J., & Trächtler, A. (2024). Adaptive Data‐Driven
Models in Port‐Hamiltonian Form for Control Design. PAMM, 25(1).
https://doi.org/10.1002/pamm.202400154
bibtex: '@article{Junker_Timmermann_Trächtler_2024, title={Adaptive Data‐Driven
Models in Port‐Hamiltonian Form for Control Design}, volume={25}, DOI={10.1002/pamm.202400154},
number={1}, journal={PAMM}, publisher={Wiley}, author={Junker, Annika and Timmermann,
Julia and Trächtler, Ansgar}, year={2024} }'
chicago: Junker, Annika, Julia Timmermann, and Ansgar Trächtler. “Adaptive Data‐Driven
Models in Port‐Hamiltonian Form for Control Design.” PAMM 25, no. 1 (2024).
https://doi.org/10.1002/pamm.202400154.
ieee: 'A. Junker, J. Timmermann, and A. Trächtler, “Adaptive Data‐Driven Models
in Port‐Hamiltonian Form for Control Design,” PAMM, vol. 25, no. 1, 2024,
doi: 10.1002/pamm.202400154.'
mla: Junker, Annika, et al. “Adaptive Data‐Driven Models in Port‐Hamiltonian Form
for Control Design.” PAMM, vol. 25, no. 1, Wiley, 2024, doi:10.1002/pamm.202400154.
short: A. Junker, J. Timmermann, A. Trächtler, PAMM 25 (2024).
date_created: 2025-01-01T16:11:38Z
date_updated: 2025-09-03T09:33:23Z
department:
- _id: '153'
- _id: '880'
doi: 10.1002/pamm.202400154
intvolume: ' 25'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://onlinelibrary.wiley.com/doi/epdf/10.1002/pamm.202400154
oa: '1'
project:
- _id: '690'
name: 'DART: Datengetriebene Methoden in der Regelungstechnik'
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Adaptive Data‐Driven Models in Port‐Hamiltonian Form for Control Design
type: journal_article
user_id: '15402'
volume: 25
year: '2024'
...
---
_id: '59051'
abstract:
- lang: eng
text: 'Model‐based state observers require high‐quality models to deliver accurate
state estimates. However, due to time or cost shortage, modeling simplifications
or numerical issues, models often have severe inaccuracies that may lead to insufficient
and deficient control. Instead of attempting to iteratively model these deviations,
we address the challenge by the concept of joint estimation. Thus, we assume a
linear combination of suitable functions to approximate the inaccuracies. The
parameters of the linear combination are supposed to be time invariant and augment
the model''s state. Subsequently, the parameters can be identified simultaneously
to the states within the observer. Referring to the principle of Occam''s razor,
the parameters are claimed to be sparse. Our former work shows that estimating
states and model inaccuracies simultaneously by a sparsity promoting unscented
Kalman filter yields not only high accuracy but also provides interpretable representations
of underlying inaccuracies. Based on this work, our contribution is twofold: First,
we apply our approach finally on a real‐world test bench, namely a golf robot.
Within the experimental setting, we investigate closed loop behavior as well as
how suitable functions need to be chosen to approximate the inaccuracies in a
physically interpretable way. Results do not only provide high state estimation
accuracy but also meaningful insights into the system''s inaccuracies. Second,
we discuss and establish a method to automatically adapt and update the model
based on collected data of the linear combination during operation. Examining
past parameter estimates by principal component analysis, a moving window is utilized
to extract the most dominant functions. These are kept characterizing the model
inaccuracies, while nondominant functions are automatically neglected and refilled
with novel function candidates. After analysis and rebuilding, this updated function
set is subsequently fed back into the joint estimation loop and deployed for further
estimation. Hence, we give a holistic paradigm of how to analyze and combat model
inaccuracies while ensuring high state estimation accuracy. Within this setting,
we once more investigate closed loop behavior and yield promising results. In
conclusion, we show that the proposed observer provides a helpful tool to guarantee
high estimation accuracy for models with severe inaccuracies or for situations
with occurring deviations during operation, for example, due to mechanical wear
or temperature changes.'
author:
- first_name: Ricarda-Samantha
full_name: Götte, Ricarda-Samantha
id: '43992'
last_name: Götte
- first_name: Julia
full_name: Timmermann, Julia
id: '15402'
last_name: Timmermann
citation:
ama: Götte R-S, Timmermann J. Online Learning With Joint State and Model Estimation.
PAMM. 2024;25(1). doi:10.1002/pamm.202400080
apa: Götte, R.-S., & Timmermann, J. (2024). Online Learning With Joint State
and Model Estimation. PAMM, 25(1). https://doi.org/10.1002/pamm.202400080
bibtex: '@article{Götte_Timmermann_2024, title={Online Learning With Joint State
and Model Estimation}, volume={25}, DOI={10.1002/pamm.202400080},
number={1}, journal={PAMM}, publisher={Wiley}, author={Götte, Ricarda-Samantha
and Timmermann, Julia}, year={2024} }'
chicago: Götte, Ricarda-Samantha, and Julia Timmermann. “Online Learning With Joint
State and Model Estimation.” PAMM 25, no. 1 (2024). https://doi.org/10.1002/pamm.202400080.
ieee: 'R.-S. Götte and J. Timmermann, “Online Learning With Joint State and Model
Estimation,” PAMM, vol. 25, no. 1, 2024, doi: 10.1002/pamm.202400080.'
mla: Götte, Ricarda-Samantha, and Julia Timmermann. “Online Learning With Joint
State and Model Estimation.” PAMM, vol. 25, no. 1, Wiley, 2024, doi:10.1002/pamm.202400080.
short: R.-S. Götte, J. Timmermann, PAMM 25 (2024).
date_created: 2025-03-17T07:06:12Z
date_updated: 2025-09-03T10:36:10Z
department:
- _id: '153'
- _id: '880'
doi: 10.1002/pamm.202400080
intvolume: ' 25'
issue: '1'
language:
- iso: eng
project:
- _id: '690'
name: 'DART: Datengetriebene Methoden in der Regelungstechnik'
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: Online Learning With Joint State and Model Estimation
type: journal_article
user_id: '15402'
volume: 25
year: '2024'
...
---
_id: '48464'
abstract:
- lang: eng
text: AbstractInitial value problems can be solved
efficiently by means of Runge–Kutta algorithms with adaptive step size control.
Diagonally implicit Runge–Kutta (DIRK) methods are the most popular class among
the diverse family of Runge–Kutta algorithms. In this paper, the novel class of
low‐order explicit last‐stage diagonally implicit Runge–Kutta (ELDIRK) methods
are explored, which combine implicit schemes with an additional explicit evaluation
as an explicit last stage. ELDIRK Butcher tableaus are used to control embedded
RK methods to obtain solutions of different orders. The lower‐order solution is
obtained by classical implicit RK stages and the higher‐order solution is obtained
by additional explicit evaluation. As a result, a significant reduction in computational
cost is achieved by skipping the iterative solution of nonlinear systems for the
additional step. The examination of the heat problem and the use of the innovative
Butcher tableau in the finite‐element method are the main contributions of this
work. Thus, it is possible to establish adaptive step size control for the new
low‐order embedded methods based on an empirical method for error estimation.
Two‐dimensional simulations are used to show an appropriate algorithm for the
ELDIRK schemes. The new Runge–Kutta schemes' predictions of higher‐order convergence
are confirmed, and their successful outcomes are illustrated.
author:
- first_name: Hendrik
full_name: Westermann, Hendrik
id: '60816'
last_name: Westermann
orcid: 0000-0002-5034-9708
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Westermann H, Mahnken R. Numerical investigations of new low‐order explicit
last stage diagonal implicit Runge–Kutta schemes with the finite‐element method.
PAMM. 2023;23(2). doi:10.1002/pamm.202300071
apa: Westermann, H., & Mahnken, R. (2023). Numerical investigations of new low‐order
explicit last stage diagonal implicit Runge–Kutta schemes with the finite‐element
method. PAMM, 23(2). https://doi.org/10.1002/pamm.202300071
bibtex: '@article{Westermann_Mahnken_2023, title={Numerical investigations of new
low‐order explicit last stage diagonal implicit Runge–Kutta schemes with the finite‐element
method}, volume={23}, DOI={10.1002/pamm.202300071},
number={2}, journal={PAMM}, publisher={Wiley}, author={Westermann, Hendrik and
Mahnken, Rolf}, year={2023} }'
chicago: Westermann, Hendrik, and Rolf Mahnken. “Numerical Investigations of New
Low‐order Explicit Last Stage Diagonal Implicit Runge–Kutta Schemes with the Finite‐element
Method.” PAMM 23, no. 2 (2023). https://doi.org/10.1002/pamm.202300071.
ieee: 'H. Westermann and R. Mahnken, “Numerical investigations of new low‐order
explicit last stage diagonal implicit Runge–Kutta schemes with the finite‐element
method,” PAMM, vol. 23, no. 2, 2023, doi: 10.1002/pamm.202300071.'
mla: Westermann, Hendrik, and Rolf Mahnken. “Numerical Investigations of New Low‐order
Explicit Last Stage Diagonal Implicit Runge–Kutta Schemes with the Finite‐element
Method.” PAMM, vol. 23, no. 2, Wiley, 2023, doi:10.1002/pamm.202300071.
short: H. Westermann, R. Mahnken, PAMM 23 (2023).
date_created: 2023-10-25T10:46:57Z
date_updated: 2023-11-07T14:34:44Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202300071
intvolume: ' 23'
issue: '2'
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Numerical investigations of new low‐order explicit last stage diagonal implicit
Runge–Kutta schemes with the finite‐element method
type: journal_article
user_id: '335'
volume: 23
year: '2023'
...
---
_id: '49866'
abstract:
- lang: eng
text: AbstractThe use of heterogeneous materials,
such as composites with Prandtl‐Reuss‐type material laws, has increased in industrial
praxis, making finite element modeling with homogenization techniques a well‐accepted
tool. These methods are particularly advantageous to account for microstructural
mechanisms which can be related to nonlinearities and time‐dependency due to elasto‐plasticity
behavior. However, their advantages are diminished by increasing computational
demand. The present contribution deals with the balance of accuracy and numerical
efficiency of nonlinear homogenization associated with a framework of goal‐oriented
adaptivity, which takes into account error accumulation over time. To this end,
model adaptivity of homogenization methods is coupled to mesh adaptivity on the
macro scale. Our new proposed adaptive procedure is driven by a goal‐oriented
a posteriori error estimator based on duality techniques using downwind and upwind
approximations. Due to nonlinearities and time‐dependency of the plasticity, the
estimation of error transport and error generation is obtained with a backward‐in‐time
dual method despite a high demand on memory capacity. In this contribution, the
dual problem is solved with a forward‐in‐time dual method that allows estimating
the full error during the resolution of the primal problem without the need for
extra memory capacity. Finally, a numerical example illustrates the effectiveness
of the proposed adaptive approach.
author:
- first_name: Arnold
full_name: Tchomgue Simeu, Arnold
id: '83075'
last_name: Tchomgue Simeu
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Tchomgue Simeu A, Mahnken R. Downwind and upwind approximations for mesh and
model adaptivity of elasto‐plastic composites. PAMM. Published online 2023.
doi:10.1002/pamm.202300136
apa: Tchomgue Simeu, A., & Mahnken, R. (2023). Downwind and upwind approximations
for mesh and model adaptivity of elasto‐plastic composites. PAMM. https://doi.org/10.1002/pamm.202300136
bibtex: '@article{Tchomgue Simeu_Mahnken_2023, title={Downwind and upwind approximations
for mesh and model adaptivity of elasto‐plastic composites}, DOI={10.1002/pamm.202300136},
journal={PAMM}, publisher={Wiley}, author={Tchomgue Simeu, Arnold and Mahnken,
Rolf}, year={2023} }'
chicago: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Downwind and Upwind Approximations
for Mesh and Model Adaptivity of Elasto‐plastic Composites.” PAMM, 2023.
https://doi.org/10.1002/pamm.202300136.
ieee: 'A. Tchomgue Simeu and R. Mahnken, “Downwind and upwind approximations for
mesh and model adaptivity of elasto‐plastic composites,” PAMM, 2023, doi:
10.1002/pamm.202300136.'
mla: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Downwind and Upwind Approximations
for Mesh and Model Adaptivity of Elasto‐plastic Composites.” PAMM, Wiley,
2023, doi:10.1002/pamm.202300136.
short: A. Tchomgue Simeu, R. Mahnken, PAMM (2023).
date_created: 2023-12-19T12:20:05Z
date_updated: 2023-12-19T12:20:51Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202300136
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Downwind and upwind approximations for mesh and model adaptivity of elasto‐plastic
composites
type: journal_article
user_id: '335'
year: '2023'
...
---
_id: '52219'
abstract:
- lang: eng
text: AbstractCold‐box sand (CBS) belongs to the
granular materials and consists of sand and a binder. The behavior of CBS is simulated
with a micropolar model, whereby the additional degree of freedom of the model
describes the rotation of the sand grains. The model is used to generate a shear
band under pressure for three different meshes, where the force‐displacement curves
of the three meshes converge so that no mesh dependence occurs. Another requirement
of the model is the consideration of asymmetric behavior for compression and tension.
Due to the additional degree of freedom the implicit implementation of the micropolar
continuum is very time‐consuming. Therefore, an explicit implementation is considered
as an alternative possibility. This paper compares the advantages and disadvantages
of both methods and the results for both calculations.
author:
- first_name: Alexander
full_name: Börger, Alexander
last_name: Börger
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Börger A, Mahnken R. A micropolar model accounting for asymmetric behavior
of cold‐box sand in relation to tensile and compression tests. PAMM. Published
online 2023. doi:10.1002/pamm.202300126
apa: Börger, A., & Mahnken, R. (2023). A micropolar model accounting for asymmetric
behavior of cold‐box sand in relation to tensile and compression tests. PAMM.
https://doi.org/10.1002/pamm.202300126
bibtex: '@article{Börger_Mahnken_2023, title={A micropolar model accounting for
asymmetric behavior of cold‐box sand in relation to tensile and compression tests},
DOI={10.1002/pamm.202300126},
journal={PAMM}, publisher={Wiley}, author={Börger, Alexander and Mahnken, Rolf},
year={2023} }'
chicago: Börger, Alexander, and Rolf Mahnken. “A Micropolar Model Accounting for
Asymmetric Behavior of Cold‐box Sand in Relation to Tensile and Compression Tests.”
PAMM, 2023. https://doi.org/10.1002/pamm.202300126.
ieee: 'A. Börger and R. Mahnken, “A micropolar model accounting for asymmetric behavior
of cold‐box sand in relation to tensile and compression tests,” PAMM, 2023,
doi: 10.1002/pamm.202300126.'
mla: Börger, Alexander, and Rolf Mahnken. “A Micropolar Model Accounting for Asymmetric
Behavior of Cold‐box Sand in Relation to Tensile and Compression Tests.” PAMM,
Wiley, 2023, doi:10.1002/pamm.202300126.
short: A. Börger, R. Mahnken, PAMM (2023).
date_created: 2024-02-29T13:59:12Z
date_updated: 2024-02-29T13:59:31Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202300126
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: A micropolar model accounting for asymmetric behavior of cold‐box sand in relation
to tensile and compression tests
type: journal_article
user_id: '335'
year: '2023'
...
---
_id: '54282'
abstract:
- lang: eng
text: AbstractStretching of polycarbonate films
leads to the formation of shear bands in the necking zone [1]. Standard viscoplastic
material models render mesh size dependent results, which requires a mathematical
regularization. To this end, we present a finite strain gradient theory for a
viscoplastic, isotropic material model where we extend the model presented in
[2] to a micromorphic model by introducing a new micromorphic variable as an additional
degree of freedom with its first gradient [3, 4]. The variable here has the meaning
of a micro plastic strain, and is coupled with the macro plastic by a micro penalty
term, forcing the macro‐plastic strain to be close to the micro‐plastic strain
for the targeted shear band regularization effect. We have implemented the model
equations as a three dimensional initial boundary value problem in an in house
FE‐tool, to simulate different geometries with different thickness and to compare
it the experimental tests. The analysis is performed for a uniaxial tensile geometry
as well as for a biaxial tensile geometry. The numerical examples show the ability
of the model to regularize the shear bands and solve the problem of localization.
author:
- first_name: Ayoub
full_name: Hamdoun, Ayoub
id: '57708'
last_name: Hamdoun
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Hamdoun A, Mahnken R. A finite strain gradient theory for viscoplasticity by
means of micromorphic regularization. PAMM. 2023;22(1). doi:10.1002/pamm.202200074
apa: Hamdoun, A., & Mahnken, R. (2023). A finite strain gradient theory for
viscoplasticity by means of micromorphic regularization. PAMM, 22(1).
https://doi.org/10.1002/pamm.202200074
bibtex: '@article{Hamdoun_Mahnken_2023, title={A finite strain gradient theory for
viscoplasticity by means of micromorphic regularization}, volume={22}, DOI={10.1002/pamm.202200074}, number={1},
journal={PAMM}, publisher={Wiley}, author={Hamdoun, Ayoub and Mahnken, Rolf},
year={2023} }'
chicago: Hamdoun, Ayoub, and Rolf Mahnken. “A Finite Strain Gradient Theory for
Viscoplasticity by Means of Micromorphic Regularization.” PAMM 22, no.
1 (2023). https://doi.org/10.1002/pamm.202200074.
ieee: 'A. Hamdoun and R. Mahnken, “A finite strain gradient theory for viscoplasticity
by means of micromorphic regularization,” PAMM, vol. 22, no. 1, 2023, doi:
10.1002/pamm.202200074.'
mla: Hamdoun, Ayoub, and Rolf Mahnken. “A Finite Strain Gradient Theory for Viscoplasticity
by Means of Micromorphic Regularization.” PAMM, vol. 22, no. 1, Wiley,
2023, doi:10.1002/pamm.202200074.
short: A. Hamdoun, R. Mahnken, PAMM 22 (2023).
date_created: 2024-05-14T09:06:38Z
date_updated: 2024-05-14T09:15:38Z
doi: 10.1002/pamm.202200074
intvolume: ' 22'
issue: '1'
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
status: public
title: A finite strain gradient theory for viscoplasticity by means of micromorphic
regularization
type: journal_article
user_id: '57708'
volume: 22
year: '2023'
...
---
_id: '44888'
author:
- first_name: Peter
full_name: Lenz, Peter
last_name: Lenz
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Lenz P, Mahnken R. Thermo‐chemo‐mechanical modelling of a curing process combined
with mean‐field homogenization methods at large strains. PAMM. 2023;22(1).
doi:10.1002/pamm.202200214
apa: Lenz, P., & Mahnken, R. (2023). Thermo‐chemo‐mechanical modelling of a
curing process combined with mean‐field homogenization methods at large strains.
PAMM, 22(1). https://doi.org/10.1002/pamm.202200214
bibtex: '@article{Lenz_Mahnken_2023, title={Thermo‐chemo‐mechanical modelling of
a curing process combined with mean‐field homogenization methods at large strains},
volume={22}, DOI={10.1002/pamm.202200214},
number={1}, journal={PAMM}, publisher={Wiley}, author={Lenz, Peter and Mahnken,
Rolf}, year={2023} }'
chicago: Lenz, Peter, and Rolf Mahnken. “Thermo‐chemo‐mechanical Modelling of a
Curing Process Combined with Mean‐field Homogenization Methods at Large Strains.”
PAMM 22, no. 1 (2023). https://doi.org/10.1002/pamm.202200214.
ieee: 'P. Lenz and R. Mahnken, “Thermo‐chemo‐mechanical modelling of a curing process
combined with mean‐field homogenization methods at large strains,” PAMM,
vol. 22, no. 1, 2023, doi: 10.1002/pamm.202200214.'
mla: Lenz, Peter, and Rolf Mahnken. “Thermo‐chemo‐mechanical Modelling of a Curing
Process Combined with Mean‐field Homogenization Methods at Large Strains.” PAMM,
vol. 22, no. 1, Wiley, 2023, doi:10.1002/pamm.202200214.
short: P. Lenz, R. Mahnken, PAMM 22 (2023).
date_created: 2023-05-16T12:15:44Z
date_updated: 2023-05-16T12:17:50Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202200214
intvolume: ' 22'
issue: '1'
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Thermo‐chemo‐mechanical modelling of a curing process combined with mean‐field
homogenization methods at large strains
type: journal_article
user_id: '335'
volume: 22
year: '2023'
...
---
_id: '44891'
author:
- first_name: Hendrik
full_name: Westermann, Hendrik
id: '60816'
last_name: Westermann
orcid: 0000-0002-5034-9708
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Westermann H, Mahnken R. A thermodynamic framework for the phase‐field approach
considering carbide precipitation during phase transformations. PAMM. 2023;22(1).
doi:10.1002/pamm.202200080
apa: Westermann, H., & Mahnken, R. (2023). A thermodynamic framework for the
phase‐field approach considering carbide precipitation during phase transformations.
PAMM, 22(1). https://doi.org/10.1002/pamm.202200080
bibtex: '@article{Westermann_Mahnken_2023, title={A thermodynamic framework for
the phase‐field approach considering carbide precipitation during phase transformations},
volume={22}, DOI={10.1002/pamm.202200080},
number={1}, journal={PAMM}, publisher={Wiley}, author={Westermann, Hendrik and
Mahnken, Rolf}, year={2023} }'
chicago: Westermann, Hendrik, and Rolf Mahnken. “A Thermodynamic Framework for the
Phase‐field Approach Considering Carbide Precipitation during Phase Transformations.”
PAMM 22, no. 1 (2023). https://doi.org/10.1002/pamm.202200080.
ieee: 'H. Westermann and R. Mahnken, “A thermodynamic framework for the phase‐field
approach considering carbide precipitation during phase transformations,” PAMM,
vol. 22, no. 1, 2023, doi: 10.1002/pamm.202200080.'
mla: Westermann, Hendrik, and Rolf Mahnken. “A Thermodynamic Framework for the Phase‐field
Approach Considering Carbide Precipitation during Phase Transformations.” PAMM,
vol. 22, no. 1, Wiley, 2023, doi:10.1002/pamm.202200080.
short: H. Westermann, R. Mahnken, PAMM 22 (2023).
date_created: 2023-05-16T12:20:19Z
date_updated: 2023-05-16T12:21:15Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202200080
intvolume: ' 22'
issue: '1'
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: A thermodynamic framework for the phase‐field approach considering carbide
precipitation during phase transformations
type: journal_article
user_id: '335'
volume: 22
year: '2023'
...
---
_id: '44892'
author:
- first_name: Ayoub
full_name: Hamdoun, Ayoub
last_name: Hamdoun
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Hamdoun A, Mahnken R. A finite strain gradient theory for viscoplasticity by
means of micromorphic regularization. PAMM. 2023;22(1). doi:10.1002/pamm.202200074
apa: Hamdoun, A., & Mahnken, R. (2023). A finite strain gradient theory for
viscoplasticity by means of micromorphic regularization. PAMM, 22(1).
https://doi.org/10.1002/pamm.202200074
bibtex: '@article{Hamdoun_Mahnken_2023, title={A finite strain gradient theory for
viscoplasticity by means of micromorphic regularization}, volume={22}, DOI={10.1002/pamm.202200074}, number={1},
journal={PAMM}, publisher={Wiley}, author={Hamdoun, Ayoub and Mahnken, Rolf},
year={2023} }'
chicago: Hamdoun, Ayoub, and Rolf Mahnken. “A Finite Strain Gradient Theory for
Viscoplasticity by Means of Micromorphic Regularization.” PAMM 22, no.
1 (2023). https://doi.org/10.1002/pamm.202200074.
ieee: 'A. Hamdoun and R. Mahnken, “A finite strain gradient theory for viscoplasticity
by means of micromorphic regularization,” PAMM, vol. 22, no. 1, 2023, doi:
10.1002/pamm.202200074.'
mla: Hamdoun, Ayoub, and Rolf Mahnken. “A Finite Strain Gradient Theory for Viscoplasticity
by Means of Micromorphic Regularization.” PAMM, vol. 22, no. 1, Wiley,
2023, doi:10.1002/pamm.202200074.
short: A. Hamdoun, R. Mahnken, PAMM 22 (2023).
date_created: 2023-05-16T12:21:32Z
date_updated: 2023-05-16T12:23:15Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202200074
intvolume: ' 22'
issue: '1'
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: A finite strain gradient theory for viscoplasticity by means of micromorphic
regularization
type: journal_article
user_id: '335'
volume: 22
year: '2023'
...
---
_id: '44890'
author:
- first_name: Arnold
full_name: Tchomgue Simeu, Arnold
id: '83075'
last_name: Tchomgue Simeu
- first_name: Rolf
full_name: Mahnken, Rolf
id: '335'
last_name: Mahnken
citation:
ama: Tchomgue Simeu A, Mahnken R. Goal‐oriented adaptivity based on a model hierarchy
of mean‐field and full‐field homogenization methods in elasto‐plasticity. PAMM.
2023;22(1). doi:10.1002/pamm.202200053
apa: Tchomgue Simeu, A., & Mahnken, R. (2023). Goal‐oriented adaptivity based
on a model hierarchy of mean‐field and full‐field homogenization methods in elasto‐plasticity.
PAMM, 22(1). https://doi.org/10.1002/pamm.202200053
bibtex: '@article{Tchomgue Simeu_Mahnken_2023, title={Goal‐oriented adaptivity based
on a model hierarchy of mean‐field and full‐field homogenization methods in elasto‐plasticity},
volume={22}, DOI={10.1002/pamm.202200053},
number={1}, journal={PAMM}, publisher={Wiley}, author={Tchomgue Simeu, Arnold
and Mahnken, Rolf}, year={2023} }'
chicago: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Goal‐oriented Adaptivity Based
on a Model Hierarchy of Mean‐field and Full‐field Homogenization Methods in Elasto‐plasticity.”
PAMM 22, no. 1 (2023). https://doi.org/10.1002/pamm.202200053.
ieee: 'A. Tchomgue Simeu and R. Mahnken, “Goal‐oriented adaptivity based on a model
hierarchy of mean‐field and full‐field homogenization methods in elasto‐plasticity,”
PAMM, vol. 22, no. 1, 2023, doi: 10.1002/pamm.202200053.'
mla: Tchomgue Simeu, Arnold, and Rolf Mahnken. “Goal‐oriented Adaptivity Based on
a Model Hierarchy of Mean‐field and Full‐field Homogenization Methods in Elasto‐plasticity.”
PAMM, vol. 22, no. 1, Wiley, 2023, doi:10.1002/pamm.202200053.
short: A. Tchomgue Simeu, R. Mahnken, PAMM 22 (2023).
date_created: 2023-05-16T12:18:15Z
date_updated: 2023-05-25T10:02:34Z
department:
- _id: '9'
- _id: '154'
- _id: '321'
doi: 10.1002/pamm.202200053
intvolume: ' 22'
issue: '1'
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Goal‐oriented adaptivity based on a model hierarchy of mean‐field and full‐field
homogenization methods in elasto‐plasticity
type: journal_article
user_id: '335'
volume: 22
year: '2023'
...
---
_id: '46813'
abstract:
- lang: eng
text: Modelling of dynamic systems plays an important role in many engineering disciplines.
Two different approaches are physical modelling and data‐driven modelling, both
of which have their respective advantages and disadvantages. By combining these
two approaches, hybrid models can be created in which the respective disadvantages
are mitigated, with discrepancy models being a particular subclass. Here, the
basic system behaviour is described physically, that is, in the form of differential
equations. Inaccuracies resulting from insufficient modelling or numerics lead
to a discrepancy between the measurements and the model, which can be compensated
by a data‐driven error correction term. Since discrepancy methods still require
a large amount of measurement data, this paper investigates the extent to which
a single discrepancy model can be trained for a physical model with additional
parameter dependencies without the need for retraining. As an example, a damped
electromagnetic oscillating circuit is used. The physical model is realised by
a differential equation describing the electric current, considering only inductance
and capacitance; dissipation due to resistance is neglected. This creates a discrepancy
between measurement and model, which is corrected by a data‐driven model. In the
experiments, the inductance and the capacity are varied. It is found that the
same data‐driven model can only be used if additional parametric dependencies
in the data‐driven term are considered as well.
author:
- first_name: Meike Claudia
full_name: Wohlleben, Meike Claudia
id: '43991'
last_name: Wohlleben
orcid: 0009-0009-9767-7168
- first_name: Lars
full_name: Muth, Lars
id: '77313'
last_name: Muth
orcid: 0000-0002-2938-5616
- first_name: Sebastian
full_name: Peitz, Sebastian
id: '47427'
last_name: Peitz
orcid: 0000-0002-3389-793X
- first_name: Walter
full_name: Sextro, Walter
id: '21220'
last_name: Sextro
citation:
ama: 'Wohlleben MC, Muth L, Peitz S, Sextro W. Transferability of a discrepancy
model for the dynamics of electromagnetic oscillating circuits. In: Proceedings
in Applied Mathematics and Mechanics. Wiley; 2023. doi:10.1002/pamm.202300039'
apa: Wohlleben, M. C., Muth, L., Peitz, S., & Sextro, W. (2023). Transferability
of a discrepancy model for the dynamics of electromagnetic oscillating circuits.
Proceedings in Applied Mathematics and Mechanics. https://doi.org/10.1002/pamm.202300039
bibtex: '@inproceedings{Wohlleben_Muth_Peitz_Sextro_2023, title={Transferability
of a discrepancy model for the dynamics of electromagnetic oscillating circuits},
DOI={10.1002/pamm.202300039},
booktitle={Proceedings in Applied Mathematics and Mechanics}, publisher={Wiley},
author={Wohlleben, Meike Claudia and Muth, Lars and Peitz, Sebastian and Sextro,
Walter}, year={2023} }'
chicago: Wohlleben, Meike Claudia, Lars Muth, Sebastian Peitz, and Walter Sextro.
“Transferability of a Discrepancy Model for the Dynamics of Electromagnetic Oscillating
Circuits.” In Proceedings in Applied Mathematics and Mechanics. Wiley,
2023. https://doi.org/10.1002/pamm.202300039.
ieee: 'M. C. Wohlleben, L. Muth, S. Peitz, and W. Sextro, “Transferability of a
discrepancy model for the dynamics of electromagnetic oscillating circuits,” 2023,
doi: 10.1002/pamm.202300039.'
mla: Wohlleben, Meike Claudia, et al. “Transferability of a Discrepancy Model for
the Dynamics of Electromagnetic Oscillating Circuits.” Proceedings in Applied
Mathematics and Mechanics, Wiley, 2023, doi:10.1002/pamm.202300039.
short: 'M.C. Wohlleben, L. Muth, S. Peitz, W. Sextro, in: Proceedings in Applied
Mathematics and Mechanics, Wiley, 2023.'
date_created: 2023-09-06T05:18:05Z
date_updated: 2023-09-21T14:47:20Z
department:
- _id: '655'
- _id: '151'
doi: 10.1002/pamm.202300039
keyword:
- Electrical and Electronic Engineering
- Atomic and Molecular Physics
- and Optics
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://onlinelibrary.wiley.com/doi/epdf/10.1002/pamm.202300039
oa: '1'
publication: Proceedings in Applied Mathematics and Mechanics
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Transferability of a discrepancy model for the dynamics of electromagnetic
oscillating circuits
type: conference
user_id: '77313'
year: '2023'
...
---
_id: '21082'
author:
- first_name: Dominik
full_name: Itner, Dominik
last_name: Itner
- first_name: Hauke
full_name: Gravenkamp, Hauke
last_name: Gravenkamp
- first_name: Dmitrij
full_name: Dreiling, Dmitrij
id: '32616'
last_name: Dreiling
- first_name: Nadine
full_name: Feldmann, Nadine
id: '23082'
last_name: Feldmann
- first_name: Bernd
full_name: Henning, Bernd
id: '213'
last_name: Henning
citation:
ama: Itner D, Gravenkamp H, Dreiling D, Feldmann N, Henning B. Simulation of guided
waves in cylinders subject to arbitrary boundary conditions for applications in
material characterization. PAMM. 2021. doi:10.1002/pamm.202000232
apa: Itner, D., Gravenkamp, H., Dreiling, D., Feldmann, N., & Henning, B. (2021).
Simulation of guided waves in cylinders subject to arbitrary boundary conditions
for applications in material characterization. PAMM. https://doi.org/10.1002/pamm.202000232
bibtex: '@article{Itner_Gravenkamp_Dreiling_Feldmann_Henning_2021, title={Simulation
of guided waves in cylinders subject to arbitrary boundary conditions for applications
in material characterization}, DOI={10.1002/pamm.202000232},
journal={PAMM}, author={Itner, Dominik and Gravenkamp, Hauke and Dreiling, Dmitrij
and Feldmann, Nadine and Henning, Bernd}, year={2021} }'
chicago: Itner, Dominik, Hauke Gravenkamp, Dmitrij Dreiling, Nadine Feldmann, and
Bernd Henning. “Simulation of Guided Waves in Cylinders Subject to Arbitrary Boundary
Conditions for Applications in Material Characterization.” PAMM, 2021.
https://doi.org/10.1002/pamm.202000232.
ieee: D. Itner, H. Gravenkamp, D. Dreiling, N. Feldmann, and B. Henning, “Simulation
of guided waves in cylinders subject to arbitrary boundary conditions for applications
in material characterization,” PAMM, 2021.
mla: Itner, Dominik, et al. “Simulation of Guided Waves in Cylinders Subject to
Arbitrary Boundary Conditions for Applications in Material Characterization.”
PAMM, 2021, doi:10.1002/pamm.202000232.
short: D. Itner, H. Gravenkamp, D. Dreiling, N. Feldmann, B. Henning, PAMM (2021).
date_created: 2021-01-26T13:52:47Z
date_updated: 2022-01-06T06:54:44Z
department:
- _id: '49'
doi: 10.1002/pamm.202000232
language:
- iso: eng
project:
- _id: '89'
grant_number: '409779252'
name: Vollständige Bestimmung der akustischen Materialparameter von Polymeren
publication: PAMM
publication_identifier:
issn:
- 1617-7061
- 1617-7061
publication_status: published
status: public
title: Simulation of guided waves in cylinders subject to arbitrary boundary conditions
for applications in material characterization
type: journal_article
user_id: '23082'
year: '2021'
...