@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}},
}

@article{65242,
  abstract     = {{<jats:title>Abstract</jats:title>
                  <jats:p>With the growing demand for lightweight solutions to reduce emissions, especially in the transportation, automotive and aerospace sectors, recyclable, continuous fiber-reinforced plastic composite laminates with a thermoplastic matrix are of rising interest. To achieve their maximum mechanical properties, the fiber-matrix adhesion (FMA) is critical. In this work, continuous fiber-reinforced thermoplastic laminates (CFRTPL) with a polypropylene (PP) matrix and twill woven glass fiber fabrics are produced by film stacking. The films used contain different amounts of maleic-anhydride-grafted PP (MA-g-PP) as a coupling agent to produce CFRTPL of different mechanical strengths. To analyze the FMA, the CFRTPL are subjected to Charpy-impact and tensile tests. Additionally, single fiber pull-out tests (SFPT) are conducted to further investigate the effect of MA-g-PP on the FMA. The results of the SFPT show an improvement in apparent interfacial shear strength (AIFSS) when the MA-g-PP content is increased, which can be attributed to an increase in FMA. However, the research shows that MA-g-PP has a low impact on the mechanical properties if the force is applied parallel to the warp and weft threads during tensile testing and the results of the Charpy-impact testing suffer from embrittlement of the matrix material. Subsequently, the results of this study are compared to three-point flexural tests conducted in a previous study. It can be concluded that tensile and impact tests are not suited to investigate FMA on a macroscopic scale, while SFPT and flexural tests provide a better alternative.</jats:p>}},
  author       = {{Moritzer, Elmar and Brandes, Philipp and Wittler, Maurice and Claes, Leander and Wippermann, Mareen and Haag, Markus and Gries, Thomas and Henning, Bernd}},
  issn         = {{0930-777X}},
  journal      = {{International Polymer Processing}},
  publisher    = {{Walter de Gruyter GmbH}},
  title        = {{{Fiber-matrix adhesion in glass fiber reinforced thermoplastic composite laminates and its effect on mechanical properties}}},
  doi          = {{10.1515/ipp-2025-0077}},
  year         = {{2026}},
}

@inproceedings{59683,
  abstract     = {{Woven fibre-reinforced polymers are used in a variety of application, especially where a low mass to stiffness ratio is required. Of paramount importance for the tailored mechanical properties these composite materials exhibit is the type and geometry of the fibre weave. Especially continuous fibre-reinforced thermoplastic composites are fabricated as laminates and subsequently exposed to forming processes which alter the geometry of the fibres unit cell and thus the local mechanical properties of the material. An approach utilising broadband ultrasonic waves is proposed to non-destructively determine the geometry of the unit cell of the weave.

The dispersive behaviour of woven fibre-reinforced sheets is described in accordance with the Flouquet-Bloch theorem as a phononic crystal. In order to develop a model for a description of these periodically structured waveguides, the smallest repeating unit of the wave is modelled with periodic boundary conditions. The resulting dispersion diagram exhibits similarities to that of a homogeneous plate, but additionally displays a periodicity in the wavenumber regime, which correspond with the size of the unit cell. Experimental studies of the dispersive behaviour of acoustic waves in woven fibre-reinforced samples also show a periodicity in the wavenumber regime, enabling a measurement procedure of the unit cell geometry.}},
  author       = {{Wippermann, Mareen and Claes, Leander and Brandes, Philipp and Moritzer, Elmar and Henning, Bernd}},
  location     = {{Copenhagen}},
  title        = {{{Determination of the unit cell geometry in fibre-reinforced polymer sheets using guided acoustic waves}}},
  doi          = {{10.71568/DASDAGA2025.116}},
  year         = {{2025}},
}

@inproceedings{59688,
  author       = {{Claes, Leander and Zeipert, Henning and Brandes, Philipp and Moritzer, Elmar and Henning, Bernd}},
  location     = {{Copenhagen}},
  title        = {{{Assessment of Fibre-Matrix Adhesion in Reinforced Polymers by Modal Damping of Guided Acoustic Waves}}},
  doi          = {{10.71568/DASDAGA2025.052}},
  year         = {{2025}},
}

@article{59995,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>Ultrasonic transmission measurements can be used for material characterization, as the propagation time of sound waves and thus their velocity depends on the elastic material parameters. Measurement results for the elastic material parameters are acquired non-destructively using ultrasonic transmission measurements of hollow cylindrical polymer specimens. To determine the material parameters, an inverse approach is used comparing measurements with simulated data. Previous studies show that the procedure exhibits low sensitivity with respect to the shear parameters of the material. In order to increase the sensitivity, we propose to apply a spatially annular excitation on the base of the specimen. As a measure to analyse the sensitivities with respect to all parameters and their linear independence, we observe the volume of the parallelotope of the sensitivity vectors. Here, a scaled boundary finite element formulation of wave propagation in the specimen is expanded to yield derivative information directly, and a sensitivity analysis can be carried out efficiently. Finally, the results of this sensitivity analysis with regard to the annular excitation are also applied to the measurement setup.</jats:p>}},
  author       = {{Dreiling, Dmitrij and Itner, Dominik and Gravenkamp, Hauke and Claes, Leander and Birk, Carolin and Henning, Bernd}},
  issn         = {{0957-0233}},
  journal      = {{Measurement Science and Technology}},
  keywords     = {{Sensitivity analysis, Ultrasonic transducer, Guided waves, Polymers, Gram determinant}},
  publisher    = {{IOP Publishing}},
  title        = {{{Increasing the sensitivity of ultrasonic transmission measurements for elastic material parameter estimation}}},
  doi          = {{10.1088/1361-6501/add9b6}},
  volume       = {{36}},
  year         = {{2025}},
}

@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{63440,
  author       = {{Moritzer, Elmar and Brandes, Philipp and Westphal, Max Siegfried and Claes, Leander and Wippermann, Mareen and Düchting, Julia and Henning, Bernd}},
  journal      = {{WAK Jahresmagazin}},
  keywords     = {{Faser-Kunststoff-Verbunde (FKV), Faserverstärkte Kunststoffe (FVK), Organobleche, Ultraschall}},
  pages        = {{26–29}},
  title        = {{{ZERSTÖRUNGSFREIE ULTRASCHALLPRÜFUNG VON ORGANOBLECHEN}}},
  volume       = {{2025}},
  year         = {{2025}},
}

@inproceedings{62295,
  author       = {{Wippermann, Mareen and Claes, Leander}},
  booktitle    = {{2025 International Congress on Ultrasonics}},
  location     = {{Paderborn}},
  pages        = {{24----27}},
  publisher    = {{AMA Service GmbH}},
  title        = {{{Phononic crystallography of fibre-reinforced polymers using broadband acoustic waves}}},
  doi          = {{10.5162/ultrasonic2025/a1-b2}},
  year         = {{2025}},
}

@inproceedings{60502,
  author       = {{Zeipert, Henning and Claes, Leander and Stoeckel, Chris and Mulay, Shubham and Henning, Bernd}},
  location     = {{Nürnberg}},
  title        = {{{Evaluation of piezoelectric micromachined ultrasonic transducers (PMUT) for the broadband detection of ultrasonic elastic waves}}},
  doi          = {{10.5162/SMSI2025/D5.2}},
  year         = {{2025}},
}

@inproceedings{60504,
  author       = {{Nellius, Tom and Henne, Kevin and Hartinger, Maximilian and Meihost, Lars and Hetkämper, Tim and Zeipert, Henning and Claes, Leander and Henning, Bernd}},
  location     = {{Nürnberg}},
  title        = {{{Ultrasonic phased array interface using programmable I/O and microprocessor clock synchronisation}}},
  doi          = {{ 10.5162/SMSI2025/A5.4}},
  year         = {{2025}},
}

@inproceedings{62294,
  author       = {{Zeipert, Henning and Nellius, Tom and Schönlau, Nikolas and Wippermann, Mareen and Claes, Leander and Nicolai, Marcel and Prager, Jens and Henning, Bernd}},
  booktitle    = {{2025 International Congress on Ultrasonics}},
  pages        = {{207----210}},
  publisher    = {{AMA Service GmbH}},
  title        = {{{Monitoring the curing process of adhesive bonds using selective excitation of guided ultrasonic waves}}},
  doi          = {{10.5162/ultrasonic2025/c6-a3}},
  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{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}},
}

@inbook{63439,
  author       = {{Moritzer, Elmar and Brandes, Philipp and Claes, Leander and Henning, Bernd}},
  booktitle    = {{PIAE EUROPE 2025}},
  editor       = {{Wissensforum GmbH, VDI}},
  pages        = {{347–360}},
  publisher    = {{{VDI Verlag}}},
  title        = {{{Ultrasound based measurement of mechanical properties of continuous fiber reinforced thermoplastic laminates // Ultrasound based measurement of mechanical properties of continuous fiber reinforced thermoplastic laminates – A non-destructive method to identify changes in fiber matrix adhesion: A non-destructive method to identify changes in fiber matrix adhesion}}},
  doi          = {{10.51202/9783181024461-347}},
  year         = {{2025}},
}

@inproceedings{62302,
  abstract     = {{The degree of crosslinking in unidirectional prepreg materials was investigated using differential scanning calorimetry to assess their curing behavior and thermal characteristics. To complement these measurements with a non-destructive, in-situ method, the propagation properties of guided acoustic waves in cured carbon fibre-reinforced epoxy plates were analysed. Correlations between the degree of crosslinking and acoustically determined mechanical properties were drawn to enable a future non-destructive evaluation approach.}},
  author       = {{Irmak, Hayrettin and Claes, Leander and Wu, Shuang and Marten, Thorsten and Tröster, Thomas}},
  booktitle    = {{2025 International Congress on Ultrasonics}},
  isbn         = {{978-3-910600-08-9}},
  keywords     = {{fibre-reinforced polymers, differential scanning calorimetry, degree of crosslinking, guided waves, ultrasound}},
  location     = {{Paderborn, Germany}},
  pages        = {{235–238}},
  publisher    = {{AMA Service GmbH}},
  title        = {{{Assessment of the influence of curing parameters on fibre reinforced epoxy composite properties using guided ultrasonic waves}}},
  doi          = {{10.5162/ultrasonic2025/c13-b3}},
  year         = {{2025}},
}

@inproceedings{63441,
  author       = {{Moritzer, Elmar and Brandes, Philipp and Wittler, Maurice and Claes, Leander and Wippermann, Mareen and Henning, Bernd}},
  booktitle    = {{40th International Conference of the Polymer Processing Society}},
  keywords     = {{Faser-Kunststoff-Verbunde (FKV), Faserverstärkte Kunststoffe (FVK), Organobleche, Ultraschall}},
  title        = {{{Non-destructive fiber-matrix adhesion measurement of glass fiber reinforced thermoplastic composite laminates using ultrasound}}},
  year         = {{2025}},
}