@article{30863,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>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.</jats:p>}},
  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}},
}

@misc{6560,
  author       = {{Johannesmann, Sarah}},
  title        = {{{Inverses Verfahren zur Bestimmung viskoelastischer Materialparameter}}},
  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}},
}

@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}},
}

@inproceedings{26033,
  author       = {{Zeipert, Henning and Johannesmann, Sarah and Nicolai, Marcel and Lugovtsova, Yevgeniya and Prager, Jens and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2021}},
  location     = {{Wien}},
  title        = {{{Quantifying the coupling strength of adhesively bonded materials by investigating mode repulsion regions}}},
  year         = {{2021}},
}

@inproceedings{27847,
  author       = {{Lugovtsova, Yevgeniya and Zeipert, Henning and Johannesmann, Sarah and Nicolai, Marcel and Prager, Jens and Henning, Bernd}},
  booktitle    = {{МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ В ЕСТЕСТВЕННЫХ НАУКАХ - XXX Всероссийская школа-конференция}},
  location     = {{Perm}},
  title        = {{{К ОПРЕДЕЛЕНИЮ ПРОЧНОСТИ КЛЕЕВОГО СОЕДИНЕНИЯ В МНОГОСЛОЙНЫХ МАТЕРИАЛАХ ПУТЕМ ИССЛЕДОВАНИЯ ОБЛАСТЕЙ РАСТАЛКИВАНИЯ БЕГУЩИХ УПРУГИХ ВОЛН}}},
  year         = {{2021}},
}

@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{21082,
  author       = {{Itner, Dominik and Gravenkamp, Hauke and Dreiling, Dmitrij and Feldmann, Nadine and Henning, Bernd}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  title        = {{{Simulation of guided waves in cylinders subject to arbitrary boundary conditions for applications in material characterization}}},
  doi          = {{10.1002/pamm.202000232}},
  year         = {{2021}},
}

@phdthesis{21183,
  abstract     = {{Die präzise Kenntnis der Eigenschaften verwendeter Materialien hat große Bedeutung für den Entwurf technischer Systeme aller Art, aber auch für die Überwachung solcher Systeme im Betrieb. Für verschiedene physikalische Eigenschaften, Betriebsbedingungen und Materialklassen werden daher geeignete messtechnische Verfahren zur Materialcharakterisierung benötigt. In der vorliegenden Arbeit wird ein Verfahren zur ultraschallbasierten Charakterisierung der mechanischen Eigenschaften von homogenen und faserverstärkten thermoplastischen Polymeren unter Berücksichtigung der Richtungsabhängigkeit vorgestellt. Plattenförmige Probekörper werden dazu mittels Laser-Pulsen hoher Energie breitbandig angeregt und die resultierenden akustischen Lamb-Wellen aufgezeichnet. Auf Basis der dispersiven Eigenschaften der detektierten Wellenleitermoden werden in einem inversen Verfahren die Parameter eines linear-elastischen Materialmodells identifiziert. Darüber hinaus wird ein Verfahren zur vollständigen Charakterisierung der Richtungsabhängigkeit in orthotropen Materialien wie Faserverbundwerkstoffen unter Verwendung eines zweidimensionalen Simulationsmodells vorgestellt. Das Messverfahren wird anhand einer Untersuchungsreihe an künstlich gealterten Polymer- und Faserverbundwerkstoffen verifiziert und die Übertragbarkeit der Ergebnisse auf den quasistatischen Fall betrachtet. Im Vergleich mit den Ergebnissen mechanischer Zugversuche werden die Voraussetzungen und Einschränkungen, insbesondere durch die Annahme eines ideal-elastischen Materialmodells, diskutiert.}},
  author       = {{Webersen, Manuel}},
  publisher    = {{Universitätsbibliothek Paderborn}},
  title        = {{{Zerstörungsfreie Charakterisierung der elastischen Materialeigenschaften thermoplastischer Polymerwerkstoffe mittels Ultraschall}}},
  doi          = {{10.17619/UNIPB/1-1088}},
  year         = {{2021}},
}

@misc{21564,
  author       = {{Itner, Dominik and Gravenkamp, Hauke and Dreiling, Dmitrij and Feldmann, Nadine and Henning, Bernd}},
  title        = {{{On the forward simulation and cost functions for the ultrasonic material characterization of polymers }}},
  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}},
}

@article{22925,
  author       = {{Claes, Leander and Chatwell, René Spencer and Baumhögger, Elmar and Hetkämper, Tim and Zeipert, Henning and Vrabec, Jadran and Henning, Bernd}},
  issn         = {{0263-2241}},
  journal      = {{Measurement}},
  title        = {{{Measurement procedure for acoustic absorption and bulk viscosity of liquids}}},
  doi          = {{10.1016/j.measurement.2021.109919}},
  year         = {{2021}},
}

@article{27367,
  abstract     = {{An approach for the non-destructive characterisation of adhesive bonds using guided ultrasonic waves is presented. Pulsed laser radiation is used to thermoacoustically excite broadband ultrasonic waves in a multi-layered sample, consisting of a metal plate adhesively joined to a polymeric layer using synthetic resin. The resulting signals are received by a purpose-built piezoelectric transducer. Varying the distance between excitation and detection yields spatio-temporal measurement data, from which the dispersive properties of the propagating waves can be inferred using a two-dimensional Fourier transform, assuming the plates to act as coupled waveguides. Coupled multi-layered waveguides show an effect referred to as <jats:italic>mode repulsion</jats:italic>, where the distance between certain modes in the frequency-wavenumber domain is assumed to be a measure of coupling strength. Measurements at different stages of curing of the adhesive layer are performed and evaluated. A comparison of the results shows changes in the dispersive properties, namely an increased modal bandwidth for the fully cured sample as well as an increased modal distance.}},
  author       = {{Zeipert, Henning and Claes, Leander and Johannesmann, Sarah and Lugovtsova, Yevgeniya and Nicolai, Marcel and Prager, Jens and Henning, Bernd}},
  issn         = {{2196-677X}},
  journal      = {{at - Automatisierungstechnik}},
  pages        = {{962--969}},
  title        = {{{An approach to adhesive bond characterisation using guided acoustic waves in multi-layered plates}}},
  doi          = {{10.1515/auto-2021-0089}},
  year         = {{2021}},
}

@inproceedings{25880,
  author       = {{Hetkämper, Tim and Dreiling, Dmitrij and Claes, Leander and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2021}},
  title        = {{{Tomographie des Schallfelds von Ultraschallwandlern mittels Schlierentechnik}}},
  year         = {{2021}},
}

@inproceedings{25265,
  abstract     = {{Waveguide-based methods can be used for the non-destructive determination of acoustic material parameters. One of these methods is based on transmission measurements of cylindrical polymeric specimens. Here, the experimental setup consists of two transducers, which excite and receive the waveguide modes at the faces of the cylinder. The measurement, as well as a forward model, are used to determine material parameters of the polymeric specimen in an inverse approach.
1-3 piezoelectric composites are used as an active element because they can be approximated by a thickness vibration only. This allows an easy identification of Mason model parameters to characterise the transducers’ vibration behaviour. 
However, sensitivity analysis shows a high uncertainty in the determination of the mechanical shear parameters due to the uniform excitation. To increase the sensitivity to these shear motions, arbitrary excitations were investigated by means of numerical simulation. 
In order to be able to realise the determined optimal excitation, new transducer prototypes were designed. By subdividing the electrodes of the active element, for example, ring-shaped excitation is feasible. Furthermore, it can be shown that modelling these transducers with a one-dimensional Mason model is sufficient.}},
  author       = {{Dreiling, Dmitrij and Itner, Dominik and Feldmann, Nadine and Scheidemann, Claus and Gravenkamp, Hauke and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2021}},
  location     = {{Wien}},
  publisher    = {{Deutsche Gesellschaft für Akustik e.V. (DEGA)}},
  title        = {{{Application and modelling of ultrasonic transducers using 1-3 piezoelectric composites with structured electrodes}}},
  year         = {{2021}},
}

@phdthesis{21502,
  abstract     = {{Die vollständige Beschreibung fluiddynamischer und akustischer Vorgänge setzt voraus, dass die Eigenschaften des Fluids hinlänglich bekannt sind.Während Fluidkenngrößen, wie etwa die Schallgeschwindigkeit oder die Scherviskosität, für viele Flüssigkeiten über weite Bereiche des thermodynamischen Zustandsraums bekannt sind, existieren für die Volumenviskosität nur eine geringe Anzahl Messdaten.In dieser Arbeit wird daher ein Messverfahren zur selektiven Bestimmung der Volumenviskosität von Flüssigkeiten, basierend auf der Absorption von Ultraschallwellen, entwickelt und realisiert.Schwerpunkte bilden dabei der simulationsgestützte Entwurf von Algorithmen zur Auswertung der Messsignale sowie die Analyse und Weiterentwicklung einer Messanordnung, basierend auf dem Puls-Echo-Verfahren. Neben der Absorption im Fluid treten dabei weitere Effekte (zum Beispiel Beugung oder unvollständige Reflexion) auf, die das akustische Signal schwächen oder anderweitig beeinflussen. Die Entwicklung von Verfahren zur Trennung dieser Effekte von der akustischen Absorption bildet daher einen weiteren Schwerpunkt dieser Arbeit.Abschließend wird die Volumenviskosität aus der gemessenen akustischen Absorption für unterschiedliche Fluide in verschiedenen thermodynamischen Zuständen unter Zuhilfenahme anderer bekannter Fluidkenngrößen bestimmt sowie eine Unsicherheitsbetrachtung durchgeführt.}},
  author       = {{Claes, Leander}},
  pages        = {{223}},
  publisher    = {{Universiät Paderborn}},
  title        = {{{Messverfahren für die akustische Absorption in reinen Fluiden zur Bestimmung der Volumenviskosität}}},
  doi          = {{10.17619/UNIPB/1-1104}},
  year         = {{2021}},
}

@inproceedings{40541,
  author       = {{Itner, D. and Gravenkamp, H. and Dreiling, Dmitrij and Feldmann, Nadine and Henning, Bernd}},
  booktitle    = {{14th WCCM-ECCOMAS Congress}},
  publisher    = {{CIMNE}},
  title        = {{{Simulation of Guided Waves in Cylinders Subject to Arbitrary Boundary Conditions Using the Scaled Boundary Finite Element Method}}},
  doi          = {{10.23967/wccm-eccomas.2020.307}},
  volume       = {{700}},
  year         = {{2021}},
}