@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}},
}

@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}},
}

@article{21232,
  author       = {{Itner, Dominik and Gravenkamp, Hauke and Dreiling, Dmitrij and Feldmann, Nadine and Henning, Bernd}},
  issn         = {{0041-624X}},
  journal      = {{Ultrasonics}},
  title        = {{{Efficient semi-analytical simulation of elastic guided waves in cylinders subject to arbitrary non-symmetric loads}}},
  doi          = {{10.1016/j.ultras.2021.106389}},
  year         = {{2021}},
}

@phdthesis{6563,
  abstract     = {{Designprozesse von Schallwandlern werden durch zunehmende Rechenkapazitäten immer mehr durch simulative Betrachtungen unterstützt. Dabei ist vor allem die Wahl der Materialparameter der verwendeten Materialien wichtig für ein realitätsnahes Simulationsergebnis. Bei Schallwandlern werden häufig Piezokeramiken als aktive Elemente genutzt, welche sich durch eine Verkopplung mechanischer und elektrischer Eigenschaften auszeichnen. Zur Bestimmung ihrer Materialparameter stellt der IEEE Standard on Piezoelectricity ein standardisiertes Verfahren dar. Dazu sind fünf Impedanzmessungen an vier unterschiedlich gefertigten Probekörpergeometrien notwendig. Da an jedem einzelnen Probekörper nur eine Untermenge aller notwendigen Materialparameter bestimmt werden kann, werden diese dann zu einem kompletten Materialparametersatz zusammengefügt. Aufgrund der unterschiedlichen Prozessbedingungen, bei denen die jeweiligen Probekörper hergestellt werden, ist dieser Materialparametersatz jedoch inkonsistent und kann nie das Verhalten einer einzelnen Probe beschreiben. Daher wird in der vorliegenden Arbeit ein Messverfahren entwickelt, mit dem es möglich ist, alle relevanten Materialparameter unter besonderer Berücksichtigung von Dämpfung an einem einzelnen Probekörper allein durch Impedanzmessungen zu bestimmen. Als Probekörper wird dazu eine in der Anwendung häufig verwendete Scheibengeometrie verwendet. Um eine hinreichend hohe Sensitivität auf alle Materialparameter zu gewährleisten, wird diese mit einer optimierten Elektrodentopologie gefertigt. Da in diesem Fall keine analytische Betrachtung mehr möglich ist, wird das Messverfahren durch einen inversen Ansatz realisiert.}},
  author       = {{Feldmann, Nadine}},
  pages        = {{184}},
  publisher    = {{Universität Paderborn}},
  title        = {{{	 Ein modellbasiertes Messverfahren zur Charakterisierung von Piezokeramiken unter Verwendung eines einzelnen scheibenförmigen Probekörpers}}},
  doi          = {{10.17619/UNIPB/1-1264}},
  year         = {{2021}},
}

@article{21341,
  abstract     = {{The progress in numerical methods and simulation tools promotes the use of inverse problems in material characterisation problems. A newly developed procedure can be used to identify the behaviour of piezoceramic discs over a wide frequency range using a single specimen via fitting simulated and measured impedances by optimising the underlying material parameters. Since there is no generally accepted damping model for piezoelectric ceramics, several mechanical damping models are examined for the material identification. Three models have been chosen and their ability to replicate the measured impedances is evaluated. On the one hand, the common Rayleigh model is considered as a reference. On the other hand, a Zener model and a model using complex constants are extended to model the transversely isotropic material. As the Rayleigh model is only valid for a limited frequency range, it fails to model the broadband behaviour of the material. The model using complex constants leads to the best fit over a wide frequency range while at the same time only adding three additional parameters for modelling damping. Thus, damping can be assumed approximately frequency-independent in piezoceramics.}},
  author       = {{Feldmann, Nadine and Schulze, Veronika and Claes, Leander and Jurgelucks, Benjamin and Meihost, Lars and Walther, Andrea and Henning, Bernd}},
  issn         = {{2196-7113}},
  journal      = {{tm - Technisches Messen}},
  number       = {{5}},
  pages        = {{294 -- 302}},
  title        = {{{Modelling damping in piezoceramics: A comparative study}}},
  doi          = {{10.1515/teme-2020-0096}},
  volume       = {{88}},
  year         = {{2021}},
}

@inproceedings{22012,
  author       = {{Claes, Leander and Feldmann, Nadine and Jurgelucks, Benjamin and Schulze, Veronika and Schmidt, Stephan and Walther, Andrea and Henning, Bernd}},
  location     = {{Nürnberg}},
  pages        = {{237--238}},
  title        = {{{Optimised Multi-Electrode Topology for Piezoelectric Material Characterisation}}},
  doi          = {{10.5162/SMSI2021/A10.1}},
  year         = {{2021}},
}

@misc{21233,
  author       = {{Schulze, Veronika and Schmidt, Stephan and Jurgelucks, Benjamin and Feldmann, Nadine and Claes, Leander}},
  title        = {{{Optimal experiment design with respect to electrode configurations for a piezoelectric problem}}},
  year         = {{2021}},
}

@misc{23462,
  author       = {{Schulze, Veronika and Schmidt, Stephan and Jurgelucks, Benjamin and Feldmann, Nadine and Claes, Leander}},
  title        = {{{Piezoelectric BC Modeling for Electrode Shapes with OED}}},
  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}},
}

@inbook{17352,
  author       = {{Moritzer, Elmar and Hüttner, Matthias and Henning, Bernd and Webersen, Manuel}},
  booktitle    = {{Advances in Polymer Processing 2020}},
  editor       = {{Hopmann, Christian and Dahlmann, Rainer}},
  isbn         = {{9783662608081}},
  location     = {{Aachen}},
  publisher    = {{Springer}},
  title        = {{{The Influence of Hydrothermal Aging on the Material Properties of Continuous Fiber-Reinforced Thermoplastics and its Non-Destructive Characterization}}},
  doi          = {{10.1007/978-3-662-60809-8_16}},
  year         = {{2020}},
}

@article{18850,
  abstract     = {{<p>The impact of the recombination mechanisms in luminescent materials is discussed with regard to luminescence based gas-sensing applications and the use of semiconducting materials, as an alternative to organic–metal complexes, is outlined.</p>}},
  author       = {{Poeplau, Michael and Ester, Stephan and Henning, Bernd and Wagner, Thorsten}},
  issn         = {{1463-9076}},
  journal      = {{Physical Chemistry Chemical Physics}},
  title        = {{{Recombination mechanisms of luminescence type gas sensors}}},
  doi          = {{10.1039/d0cp02269a}},
  year         = {{2020}},
}

@inproceedings{17089,
  author       = {{Dreiling, Dmitrij and Itner, Dominik Thor and Feldmann, Nadine and Gravenkamp, Hauke and Henning, Bernd}},
  location     = {{Nürnberg}},
  publisher    = {{AMA Service GmbH}},
  title        = {{{Increasing the sensitivity in the determination of material parameters by using arbitrary loads in ultrasonic transmission measurements}}},
  doi          = {{10.5162/SMSI2020/D1.3}},
  year         = {{2020}},
}

@inproceedings{15490,
  author       = {{Claes, Leander and Baumhögger, Elmar and Rüther, Torben and Gierse, Jan and Tröster, Thomas and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2020}},
  pages        = {{1077--1080}},
  title        = {{{Reduction of systematic measurement deviation in acoustic absorption measurement systems}}},
  year         = {{2020}},
}

@inproceedings{15163,
  author       = {{Feldmann, Nadine and Schulze, Veronika and Jurgelucks, Benjamin and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2020}},
  pages        = {{1125--1128}},
  title        = {{{Solving piezoelectric inverse problems using Algorithmic Differentiation}}},
  year         = {{2020}},
}

@inproceedings{15264,
  author       = {{Johannesmann, Sarah and Becker, Sebastian and Webersen, Manuel and Henning, Bernd}},
  booktitle    = {{SMSI 2020 - Measurement Science}},
  isbn         = {{978-3-9819376-2-6}},
  location     = {{Nuremberg}},
  title        = {{{Determination of Murnaghan constants of plate-shaped polymers under uniaxial tensile load}}},
  doi          = {{10.5162/SMSI2020/D6.1}},
  year         = {{2020}},
}