@article{63435,
author = {{Claes, Leander and Winkler, Michael}},
issn = {{1468-1218}},
journal = {{Nonlinear Analysis: Real World Applications}},
pages = {{104580}},
publisher = {{Elsevier BV}},
title = {{{Describing smooth small-data solutions to a quasilinear hyperbolic-parabolic system by W 1,P energy analysis}}},
doi = {{10.1016/j.nonrwa.2025.104580}},
volume = {{91}},
year = {{2026}},
}
@inproceedings{62300,
author = {{Claes, Leander and Hölscher, Jonas and Friesen, Olga and Scheidemann, Claus and Hemsel, Tobias and Henning, Bernd}},
booktitle = {{2025 International Congress on Ultrasonics}},
pages = {{142–145}},
publisher = {{AMA Service GmbH}},
title = {{{Estimation of third order elastic constants of piezoceramics using DC biased impedance measurements}}},
doi = {{10.5162/ultrasonic2025/a18-a6}},
year = {{2025}},
}
@inproceedings{62296,
author = {{Spieker, Carsten and Förstner, Jens and Hölscher, Jonas and Claes, Leander and Henning, Bernd}},
booktitle = {{2025 International Congress on Ultrasonics}},
pages = {{126–129}},
publisher = {{AMA Service GmbH}},
title = {{{Modeling and simulation of the behavior of piezoceramics with the discontinuous Galerkin method}}},
doi = {{10.5162/ultrasonic2025/a18-a1}},
year = {{2025}},
}
@inproceedings{62297,
author = {{Hölscher, Jonas and Friesen, Olga and Claes, Leander and Spieker, Carsten and Förstner, Jens and Henning, Bernd}},
booktitle = {{2025 International Congress on Ultrasonics}},
pages = {{130–133}},
publisher = {{AMA Service GmbH}},
title = {{{Multiscale thermo-piezoelectric simulations using the finite element method}}},
doi = {{10.5162/ultrasonic2025/a18-a2}},
year = {{2025}},
}
@article{59258,
author = {{Winkler, Michael}},
issn = {{0095-4616}},
journal = {{Applied Mathematics & Optimization}},
number = {{2}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Rough Data in an Evolution System Generalizing 1D Thermoviscoelasticity with Temperature-Dependent Parameters}}},
doi = {{10.1007/s00245-025-10243-9}},
volume = {{91}},
year = {{2025}},
}
@inproceedings{61755,
author = {{Scheidemann, Claus and Hemsel, Tobias and Sextro, Walter}},
location = {{Vilnius, Lithuania}},
title = {{{Time dependent material characteristics of prestressed piezoelectric ceramics in langevin transducers}}},
year = {{2025}},
}
@inproceedings{61757,
author = {{Scheidemann, Claus and Porzenheim, Julius and Hemsel, Tobias and Sextro, Walter}},
location = {{Paderborn, Germany}},
title = {{{Investigation of the Setting Behaviour of Mechanically Biased Piezoelectric Ultrasonic Transducers}}},
year = {{2025}},
}
@article{62000,
author = {{Claes, Leander and Koch, Kevin and Friesen, Olga and Meihost, Lars}},
issn = {{2681-4617}},
journal = {{Acta Acustica}},
number = {{65}},
publisher = {{EDP Sciences}},
title = {{{Machine Learning-Supported Inverse Measurement Procedure for Broadband, Temperature Dependent Piezoelectric Material Parameters}}},
doi = {{10.1051/aacus/2025044}},
volume = {{9}},
year = {{2025}},
}
@article{54837,
author = {{Claes, Leander and Lankeit, Johannes and Winkler, Michael}},
issn = {{1793-6314}},
journal = {{Mathematical Models and Methods in Applied Sciences}},
number = {{11}},
pages = {{2465--2512}},
publisher = {{World Scientific Pub Co Pte Ltd}},
title = {{{A model for heat generation by acoustic waves in piezoelectric materials: Global large-data solutions}}},
doi = {{10.1142/s0218202525500447}},
volume = {{35}},
year = {{2025}},
}
@inproceedings{62299,
author = {{Friesen, Olga and Scheidemann, Claus and Claes, Leander and Hemsel, Tobias and Henning, Bernd}},
booktitle = {{2025 International Congress on Ultrasonics}},
pages = {{138–141}},
publisher = {{AMA Service GmbH}},
title = {{{Sensitivity Analysis and Material Parameter Estimation of a Pre-Stressed Langevin Transducer}}},
doi = {{10.5162/ultrasonic2025/a18-a4}},
year = {{2025}},
}
@inproceedings{62298,
author = {{Kuess, Raphael and Friesen, Olga and Henning, Bernd and Walther, Andrea}},
booktitle = {{2025 International Congress on Ultrasonics}},
pages = {{134–137}},
publisher = {{AMA Service GmbH}},
title = {{{Identification of temperature-dependent material parameter functions in piezoelectricity}}},
doi = {{10.5162/ultrasonic2025/a18-a3}},
year = {{2025}},
}
@inproceedings{59689,
author = {{Friesen, Olga and Meihost, Lars and Koch, Kevin and Claes, Leander and Henning, Bernd}},
location = {{Copenhagen}},
title = {{{Estimation of piezoelectric material parameters under varying electric field conditions}}},
doi = {{10.71568/DASDAGA2025.078}},
year = {{2025}},
}
@article{63250,
abstract = {{Abstract
An initial-boundary value problem for
$$\begin{aligned} \left\{ \begin{array}{ll}u_{tt} = \big (\gamma (\Theta ) u_{xt}\big )_x + au_{xx} - \big (f(\Theta )\big )_x, \qquad & x\in \Omega , \ t>0, \\[1mm] \Theta _t = \Theta _{xx} + \gamma (\Theta ) u_{xt}^2 - f(\Theta ) u_{xt}, \qquad & x\in \Omega , \ t>0, \end{array} \right. \end{aligned}$$
u
tt
=
(
γ
(
Θ
)
u
xt
)
x
+
a
u
xx
-
(
f
(
Θ
)
)
x
,
x
∈
Ω
,
t
>
0
,
[
1
m
m
]
Θ
t
=
Θ
xx
+
γ
(
Θ
)
u
xt
2
-
f
(
Θ
)
u
xt
,
x
∈
Ω
,
t
>
0
,
is considered in an open bounded real interval
$$\Omega $$
Ω
. Under the assumption that
$$\gamma \in C^0([0,\infty ))$$
γ
∈
C
0
(
[
0
,
∞
)
)
and
$$f\in C^0([0,\infty ))$$
f
∈
C
0
(
[
0
,
∞
)
)
are such that
$$f(0)=0$$
f
(
0
)
=
0
, and
$$k_\gamma \le \gamma \le K_\gamma $$
k
γ
≤
γ
≤
K
γ
as well as
$$\begin{aligned} |f(\xi )| \le K_f \cdot (\xi +1)^\alpha \qquad \hbox {for all } \xi \ge 0 \end{aligned}$$
|
f
(
ξ
)
|
≤
K
f
·
(
ξ
+
1
)
α
for all
ξ
≥
0
with some
$$k_\gamma>0, K_\gamma>0, K_f>0$$
k
γ
>
0
,
K
γ
>
0
,
K
f
>
0
and
$$\alpha <\frac{3}{2}$$
α
<
3
2
, for all suitably regular initial data of arbitrary size a statement on global existence of a global weak solution is derived. By particularly covering the thermodynamically consistent choice
$$f\equiv id$$
f
≡
i
d
of predominant physical relevance, this appears to go beyond previous related literature which seems to either rely on independence of
$$\gamma $$
γ
on
$$\Theta $$
Θ
, or to operate on finite time intervals.
}},
author = {{Winkler, Michael}},
issn = {{0044-2275}},
journal = {{Zeitschrift für angewandte Mathematik und Physik}},
number = {{5}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Large-data solutions in one-dimensional thermoviscoelasticity involving temperature-dependent viscosities}}},
doi = {{10.1007/s00033-025-02582-y}},
volume = {{76}},
year = {{2025}},
}
@article{63249,
abstract = {{Abstract
The model
$$\begin{aligned} \left\{ \begin{array}{l}u_{tt} = \big (\gamma (\Theta ) u_{xt}\big )_x + au_{xx} - \big (f(\Theta )\big )_x, \\[1mm] \Theta _t = \Theta _{xx} + \gamma (\Theta ) u_{xt}^2 - f(\Theta ) u_{xt}, \end{array} \right. \end{aligned}$$
u
tt
=
(
γ
(
Θ
)
u
xt
)
x
+
a
u
xx
-
(
f
(
Θ
)
)
x
,
[
1
m
m
]
Θ
t
=
Θ
xx
+
γ
(
Θ
)
u
xt
2
-
f
(
Θ
)
u
xt
,
for thermoviscoelastic evolution in one-dimensional Kelvin–Voigt materials is considered. By means of an approach based on maximal Sobolev regularity theory of scalar parabolic equations, it is shown that if
$$\gamma _0>0$$
γ
0
>
0
is fixed, then there exists
$$\delta =\delta (\gamma _0)>0$$
δ
=
δ
(
γ
0
)
>
0
with the property that for suitably regular initial data of arbitrary size an associated initial boundary value problem posed in an open bounded interval admits a global classical solution whenever
$$\gamma \in C^2([0,\infty ))$$
γ
∈
C
2
(
[
0
,
∞
)
)
and
$$f\in C^2([0,\infty ))$$
f
∈
C
2
(
[
0
,
∞
)
)
are such that
$$f(0)=0$$
f
(
0
)
=
0
and
$$|f(\xi )| \le K_f \cdot (\xi +1)^\alpha $$
|
f
(
ξ
)
|
≤
K
f
·
(
ξ
+
1
)
α
for all
$$\xi \ge 0$$
ξ
≥
0
and some
$$K_f>0$$
K
f
>
0
and
$$\alpha <\frac{3}{2}$$
α
<
3
2
, and that
$$\begin{aligned} \gamma _0 \le \gamma (\xi ) \le \gamma _0 + \delta \qquad \hbox {for all } \xi \ge 0. \end{aligned}$$
γ
0
≤
γ
(
ξ
)
≤
γ
0
+
δ
for all
ξ
≥
0
.
This is supplemented by a statement on global existence of certain strong solutions, particularly continuous in both components, under weaker conditions on the initial data.
}},
author = {{Winkler, Michael}},
issn = {{1424-3199}},
journal = {{Journal of Evolution Equations}},
number = {{4}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Large-data regular solutions in a one-dimensional thermoviscoelastic evolution problem involving temperature-dependent viscosities}}},
doi = {{10.1007/s00028-025-01144-z}},
volume = {{25}},
year = {{2025}},
}
@article{63246,
abstract = {{Abstract
The hyperbolic-parabolic model
$$\begin{aligned} \left\{ \begin{array}{ll} u_{tt} = u_{xx} - \big (f(\Theta )\big )_x, \qquad & x\in \Omega , \ t>0, \\ \Theta _t = \Theta _{xx} - f(\Theta ) u_{xt}, \qquad & x\in \Omega , \ t>0, \end{array} \right. \end{aligned}$$
u
tt
=
u
xx
-
(
f
(
Θ
)
)
x
,
x
∈
Ω
,
t
>
0
,
Θ
t
=
Θ
xx
-
f
(
Θ
)
u
xt
,
x
∈
Ω
,
t
>
0
,
for the evolution of the displacement variable
u
and the temperature
$$\Theta \ge 0$$
Θ
≥
0
during thermoelastic interaction in a one-dimensional bounded interval
$$\Omega $$
Ω
is considered. Whereas the literature has provided comprehensive results on global solutions for sufficiently regular initial data
$$(u_0,u_{0t},\Theta _0)=(u,u_t,\Theta )|_{t=0}$$
(
u
0
,
u
0
t
,
Θ
0
)
=
(
u
,
u
t
,
Θ
)
|
t
=
0
when
$$f\equiv id$$
f
≡
i
d
, it seems to have remained open so far how far a solution theory can be built solely on the two fundamental physical principles of energy conservation and entropy nondecrease. The present manuscript addresses this by asserting global existence of weak solutions under assumptions which are energy- and entropy-minimal in the sense of allowing for any initial data
$$u_0\in W_0^{1,2}(\Omega )$$
u
0
∈
W
0
1
,
2
(
Ω
)
,
$$u_{0t} \in L^2(\Omega )$$
u
0
t
∈
L
2
(
Ω
)
and
$$0\le \Theta _0\in L^1(\Omega )$$
0
≤
Θ
0
∈
L
1
(
Ω
)
, and which apply to arbitrary
$$f\in C^1([0,\infty ))$$
f
∈
C
1
(
[
0
,
∞
)
)
with
$$f(0)=0$$
f
(
0
)
=
0
and
$$f'>0$$
f
′
>
0
on
$$[0,\infty )$$
[
0
,
∞
)
.
}},
author = {{Winkler, Michael}},
issn = {{0944-2669}},
journal = {{Calculus of Variations and Partial Differential Equations}},
number = {{1}},
publisher = {{Springer Science and Business Media LLC}},
title = {{{Rough solutions in one-dimensional nonlinear thermoelasticity}}},
doi = {{10.1007/s00526-025-03170-8}},
volume = {{65}},
year = {{2025}},
}
@inproceedings{53822,
abstract = {{Piezoelektrische Keramiken finden sowohl in Sensoren als auch in Aktoren Anwendung. Bei Hochleistungs-Ultraschallanwendungen sind diese Komponenten erheblichen elektrischen und mechanischen Belastungen ausgesetzt, was zum Auftreten nichtlinearer Effekte führt. Um das nichtlineare Materialverhalten piezoelektrischer Keramiken zu charakterisieren, kann eine statische mechanische Last aufgebracht werden, die den mechanischen Arbeitspunkt verschiebt. Durch Variation dieser statischen mechanischen Belastung kann das lineare Verhalten in jedem Betriebspunkt charakterisiert werden, woraufhin die nichtlinearen Eigenschaften des Materials angenähert werden können. Allerdings ist die Sicherstellung einer homogenen mechanischen Last anspruchsvoll. Alternativ kann eine hydrostatische Belastung realisiert werden, indem die Probe in einen Behälter gegeben wird, der mit unter Druck stehendem Fluid gefüllt ist. Dadurch wird eine gleichmäßige Lastverteilung über die Oberfläche der Probe erreicht.
In diesem Beitrag wird ein Versuchsaufbau zur Durchführung elektrischer Impedanzmessungen an piezoelektrischen Keramiken in einem Druckbehälter vorgestellt. Die Probe wird im Inneren des Druckbehälters elektrisch kontaktiert. Unter Verwendung von unter Druck stehendem Argon wird auf diese Weise die Messung der elektrischen Impedanz unter hydrostatischer Last von bis zu 200 bar ermöglicht. Anschließend wird ein inverses Verfahren angewendet, um die Materialparameter in Abhängigkeit von der aufgebrachten Last zu ermitteln.}},
author = {{Friesen, Olga and Pasha, Muhammad Ahsan and Schwengelbeck, Max and Claes, Leander and Baumhögger, Elmar and Henning, Bernd}},
booktitle = {{Fortschritte der Akustik - DAGA 2024}},
location = {{Hannover}},
pages = {{1117–1120}},
title = {{{Untersuchung piezoelektrischer Materialeigenschaften unter hydrostatischer Last}}},
year = {{2024}},
}
@inproceedings{53824,
author = {{Koch, Kevin and Claes, Leander and Jurgelucks, Benjamin and Meihost, Lars and Henning, Bernd}},
booktitle = {{Fortschritte der Akustik - DAGA 2024}},
editor = {{Gesellschaft für Akustik e.V., Deutsche }},
pages = {{1113–1116}},
title = {{{Inverses Verfahren zur Identifikation piezoelektrischer Materialparameter unterstützt durch neuronale Netze}}},
year = {{2024}},
}
@inproceedings{56834,
author = {{Friesen, Olga and Claes, Leander and Scheidemann, Claus and Feldmann, Nadine and Hemsel, Tobias and Henning, Bernd}},
booktitle = {{2023 International Congress on Ultrasonics, Beijing, China}},
issn = {{1742-6596}},
pages = {{012125}},
publisher = {{IOP Publishing}},
title = {{{Estimation of temperature-dependent piezoelectric material parameters using ring-shaped specimens}}},
doi = {{10.1088/1742-6596/2822/1/012125}},
volume = {{2822}},
year = {{2024}},
}
@misc{55470,
author = {{Koch, Kevin and Friesen, Olga and Claes, Leander}},
publisher = {{Zenodo}},
title = {{{Randomised material parameter impedance dataset of piezoelectric rings}}},
doi = {{10.5281/zenodo.13143680}},
year = {{2024}},
}
@misc{53662,
author = {{Koch, Kevin and Claes, Leander}},
publisher = {{zenodo}},
title = {{{Randomised material parameter piezoelectric impedance dataset with structured electrodes}}},
doi = {{10.5281/ZENODO.11064206}},
year = {{2024}},
}