@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{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{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}}, } @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}}, } @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{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{55416, author = {{Claes, Leander and Koch, Kevin and Friesen, Olga and Meihost, Lars}}, title = {{{Machine learning in inverse measurement problems: An application to piezoelectric material characterisation}}}, year = {{2024}}, } @article{56777, abstract = {{The estimation of accurate piezoelectric material parameters is a fundamental prerequisite for simulation-driven design of piezoelectric actuators and sensors. Previous studies show that a full set of material parameters can be determined in an inverse procedure using a single disc-shaped specimen with an electrode structured for increased sensitivity with respect to all material parameters. However, in the case of high-power actuator applications, ring-shaped piezoelectric components are often employed, necessitating an adaptation of the previously developed method. The alteration in geometry introduces some advantages. Accordingly, there is no longer any requirement to modify the electrode structure in order to enhance sensitivity. The method to estimate the material parameters presented here consists of a total of three stages. An initial, approximate estimation of the material parameters is determined using analytical approximations for the resonance frequencies from the IEEE standard. These values are optimised in an inverse procedure that employs analytic expressions for the electrical impedance of piezoelectric rings as the forward model. Further refinement is achieved by using Finite Element (FE) simulations as the forward model again in an inverse procedure. The method is applied to electrical impedance measurement data, yielding material parameters for hard piezoelectric rings. The result shows a good agreement between the simulation and measurement results, indicating realistic material parameter values.}}, author = {{Friesen, Olga and Claes, Leander and Feldmann, Nadine and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, publisher = {{De Gruyter}}, title = {{{Estimation of piezoelectric material parameters of ring-shaped specimens}}}, doi = {{https://doi.org/10.1515/teme-2024-0107}}, year = {{2024}}, } @inproceedings{43233, author = {{Zeipert, Henning and von Germeten, Christian and Friesen, Olga and Claes, Leander and Johannesmann, Sarah and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2023}}, location = {{Hamburg}}, pages = {{819--822}}, title = {{{Investigation of change in dispersive behaviour during adhesive curing in multi-layered structures}}}, year = {{2023}}, } @inproceedings{51117, author = {{Scheidemann, Claus and Hemsel, Tobias and Friesen, Olga and Claes, Leander and Sextro, Walter}}, location = {{Jeju, Korea}}, title = {{{Influence of Temperature and Pre-Stress on the Piezoelectric Material Behavior of Ring-Shaped Ceramics}}}, year = {{2023}}, } @misc{6558, author = {{Friesen, Olga and Claes, Leander and Feldmann, Nadine and Henning, Bernd}}, title = {{{Estimation of piezoelectric material parameters of ring-shaped specimens}}}, year = {{2022}}, }