@misc{12950, author = {{Claes, Leander and Webersen, Manuel}}, publisher = {{GitHub, Inc.}}, title = {{{pyfds 0.1.6 - modular field simulation tool}}}, doi = {{10.5281/ZENODO.2649826}}, year = {{2023}}, } @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{43229, author = {{Claes, Leander}}, booktitle = {{Fortschritte der Akustik - DAGA 2023}}, location = {{Hamburg}}, pages = {{7--14}}, title = {{{Bestimmung der Volumenviskosität mittels akustischer Absorptionsmessung}}}, year = {{2023}}, } @article{37543, author = {{Hetkämper, Tim and Koch, Kevin and Claes, Leander and Henning, Bernd}}, journal = {{tm - Technisches Messen}}, keywords = {{Schlierentechnik}}, number = {{2}}, pages = {{103--112}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Phase-preserving methods to visualise ultrasonic fields with schlieren imaging}}}, doi = {{10.1515/teme-2022-0112}}, volume = {{90}}, year = {{2023}}, } @article{45445, author = {{Claes, Leander and Feldmann, Nadine and Schulze, Veronika and Meihost, Lars and Kuhlmann, Henrik and Jurgelucks, Benjamin and Walther, Andrea and Henning, Bernd}}, journal = {{Journal of Sensors and Sensor Systems}}, number = {{1}}, pages = {{163–173}}, title = {{{Inverse procedure for measuring piezoelectric material parameters using a single multi-electrode sample}}}, doi = {{10.5194/jsss-12-163-2023}}, volume = {{12}}, year = {{2023}}, } @misc{45455, author = {{Claes, Leander and Meihost, Lars and Jurgelucks, Benjamin}}, title = {{{Inverse procedure for the identification of piezoelectric material parameters supported by dense neural networks}}}, year = {{2023}}, } @inproceedings{47138, author = {{Hetkämper, Tim and Koch, Kevin and Webersen, Manuel and Claes, Leander}}, booktitle = {{SEFI 51th Annual Conference Proceedings - Engineering Education for Sustainability}}, publisher = {{SEFI}}, title = {{{Application-based learning of signal analysis methods with the help of a graphical open-source software}}}, doi = {{10.21427/159K-G445}}, year = {{2023}}, } @article{48053, author = {{Hetkämper, Tim and Claes, Leander and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{s1}}, pages = {{49--54}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Vorzeichenrichtige tomographische Rekonstruktion von Ultraschallfeldern mit Hilfe der Schlierentechnik}}}, doi = {{10.1515/teme-2023-0069}}, volume = {{90}}, 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}}, } @inproceedings{51118, author = {{Scheidemann, Claus and Hemsel, Tobias and Friesen, Olga and Claes, Leander and Sextro, Walter}}, location = {{Incheon, Korea}}, title = {{{Influence of Temperature and Pre-Stress on the Piezoelectric Material Behavior of Ring-Shaped Ceramics}}}, year = {{2023}}, } @misc{6592, author = {{Claes, Leander}}, title = {{{Messverfahren für die akustische Absorption zur Bestimmung der Volumenviskosität}}}, year = {{2022}}, } @inproceedings{31331, author = {{Hetkämper, Tim and Claes, Leander and Henning, Bernd}}, booktitle = {{Sensoren und Messsysteme - Beiträge der 21. ITG/GMA-Fachtagung}}, isbn = {{978-3-8007-5835-7}}, location = {{Nürnberg}}, publisher = {{VDE Verlag GmbH}}, title = {{{Schlieren imaging with fractional Fourier transform to visualise ultrasonic fields}}}, year = {{2022}}, } @inproceedings{6553, author = {{Claes, Leander and Feldmann, Nadine and Schulze, Veronika and Jurgelucks, Benjamin and Walther, Andrea and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2022}}, location = {{Stuttgart}}, pages = {{1326--1329}}, title = {{{Identification of piezoelectric material parameters using optimised multi-electrode specimens}}}, year = {{2022}}, } @article{6579, abstract = {{An explicit approach using symplectic time integration in conjunction with traditional finite difference spatial derivatives to solve the wave equation in moving media is presented. A simple operator split of this second order wave equation into two coupled first order equations is performed, allowing these split equations to be solved symplectically. Orders of symplectic time integration ranging from first to fourth along with orders of spatial derivatives ranging from second to sixth are explored. The case of cylindrical acoustic spreading in air under a constant velocity in a 2D square structured domain is considered. The variation of the computed time-of-flight, frequency, and wave length are studied with varying grid resolution and the deviations from the analytical solutions are determined. It was found that symplectic time integration interferes with finite difference spatial derivatives higher than second order causing unexpected results. This is actually beneficial for unstructured finite volume tools like OpenFOAM where second order spatial operators are the state-of-the art. Cylindrical acoustic spreading is simulated on an unstructured 2D triangle mesh showing that symplectic time integration is not limited to the spatial discretization paradigm and overcomes the numerical diffusion arising with the in-built numerical methods which hinder wave propagation.}}, author = {{Inguva, Venkatesh and Feldmann, Nadine and Claes, Leander and Koturbash, Taras and Hahn-Jose, Thomas and Koutcherov, Vladimir and Kenig, Eugeny}}, journal = {{Engineering Reports}}, title = {{{An explicit symplectic approach to solving the wave equation in moving media}}}, doi = {{10.1002/eng2.12573}}, year = {{2022}}, } @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}}, } @article{30863, abstract = {{Abstract In this paper a measurement procedure to identify viscoelastic material parameters of plate-like samples using broadband ultrasonic waves is presented. Ultrasonic Lamb waves are excited via the thermoelastic effect using laser radiation and detected by a piezoelectric transducer. The resulting measurement data is transformed to yield information about multiple propagating Lamb waves as well as their attenuation. These results are compared to simulation results in an inverse procedure to identify the parameters of an elastic and a viscoelastic material model.}}, author = {{Johannesmann, Sarah and Claes, Leander and Feldmann, Nadine and Zeipert, Henning and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, keywords = {{Electrical and Electronic Engineering, Instrumentation}}, number = {{7 - 8}}, pages = {{493 -- 506}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Lamb wave based approach to the determination of acoustic material parameters}}}, doi = {{10.1515/teme-2021-0134}}, volume = {{89}}, year = {{2022}}, } @inproceedings{6588, author = {{Johannesmann, Sarah and Claes, Leander and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2022}}, location = {{Stuttgart}}, pages = {{1401--1404}}, title = {{{Estimation of viscoelastic material parameters of polymers using Lamb waves}}}, year = {{2022}}, } @article{21067, abstract = {{Acoustic waves in plates have proven a viable tool for testing and material characterisation purposes. There are a multitude of options for excitation and detection of theses waves, such as optical and piezoelectric systems. While optical systems, with thermoelastic excitation and interferometric detection, have the benefit of being contactless, they usually require rather complex and expensive experimental setups. Piezoelectric systems are more easily realised but require direct contact with the specimen and usually have a limited bandwidth, especially in case of piezoelectric excitation. In this work, the authors compare the properties of piezoelectric and optical detection methods for broad-band acoustic signals. The shape (e. g. the displacement) of a propagating plate wave is given by its frequency and wave number, allowing to investigate correlations between mode shapes and received signal strengths. This is aided by evaluations in normalised frequency and wavenumber space, facilitating comparisons of different specimens. Further, the authors explore possibilities to utilise the specific properties of the detection methods to determine acoustic material parameters.}}, author = {{Claes, Leander and Schmiegel, Hanna and Grünsteidl, Clemens and Johannesmann, Sarah and Webersen, Manuel and Henning, Bernd}}, issn = {{2196-7113}}, journal = {{tm - Technisches Messen}}, number = {{3}}, pages = {{147--155}}, title = {{{Investigating peculiarities of piezoelectric detection methods for acoustic plate waves in material characterisation applications}}}, doi = {{10.1515/teme-2020-0098}}, volume = {{88}}, year = {{2021}}, } @article{23791, author = {{Johannesmann, Sarah and Claes, Leander and Henning, Bernd}}, journal = {{tm - Technisches Messen}}, number = {{s1}}, pages = {{s28--s33}}, publisher = {{Walter de Gruyter {GmbH}}}, title = {{{Lamb wave based approach to the determination of elastic and viscoelastic material parameters}}}, doi = {{10.1515/teme-2021-0070}}, volume = {{88}}, year = {{2021}}, } @inproceedings{22013, author = {{Zeipert, Henning and Claes, Leander and Johannesmann, Sarah and Webersen, Manuel and Lugovtsova, Yevgeniya and Prager, Jens and Henning, Bernd}}, location = {{Nürnberg}}, pages = {{91 -- 92}}, title = {{{Measurement and Simulation of Lamb Waves in Adhesive-bonded Multilayer Systems}}}, doi = {{10.5162/SMSI2021/A8.2}}, year = {{2021}}, }