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Perspektivenwechsel. Bildinformationen anzeigen

Perspektivenwechsel.

Foto: Universität Paderborn

Dr.-Ing. Leander Claes

Kontakt
Publikationen
Dr.-Ing. Leander Claes

Elektrische Messtechnik (EMT)

Wissenschaftlicher Mitarbeiter - Schallfeldsimulation, Fluidcharakterisierung

Telefon:
+49 5251 60-4950
Büro:
P1.5.17.3
Besucher:
Pohlweg 47-49
33098 Paderborn

Liste im Research Information System öffnen

2021

Measurement procedure for acoustic absorption and bulk viscosity of liquids

L. Claes, R.S. Chatwell, E. Baumhögger, T. Hetkämper, H. Zeipert, J. Vrabec, B. Henning, Measurement (2021)


Investigating peculiarities of piezoelectric detection methods for acoustic plate waves in material characterisation applications

L. Claes, H. Schmiegel, C. Grünsteidl, S. Johannesmann, M. Webersen, B. Henning, tm - Technisches Messen (2021), 88(3), pp. 147-155

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.


    Optimal experiment design with respect to electrode configurations for a piezoelectric problem

    V. Schulze, S. Schmidt, B. Jurgelucks, N. Feldmann, L. Claes, 2021


    Modelling damping in piezoceramics: A comparative study

    N. Feldmann, V. Schulze, L. Claes, B. Jurgelucks, L. Meihost, A. Walther, B. Henning, tm - Technisches Messen (2021), 88(5), pp. 294 - 302

    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.


      Piezoelectric BC Modeling for Electrode Shapes with OED

      V. Schulze, S. Schmidt, B. Jurgelucks, N. Feldmann, L. Claes, 2021


      Lamb wave based approach to the determination of elastic and viscoelastic material parameters

      S. Johannesmann, L. Claes, B. Henning, tm - Technisches Messen (2021), 88(s1), pp. s28-s33


      Messverfahren für die akustische Absorption in reinen Fluiden zur Bestimmung der Volumenviskosität

      L. Claes, Universiät Paderborn, 2021

      The prerequisite for a complete description of fluid dynamic and acoustic processes is that all properties of the fluid are known.While fluid parameters such as the speed of sound or the shear viscosity are known for many liquids over a wide range of thermodynamic states, only limited measurement data exist for the bulk viscosity.In this thesis, a measurement method for the selective determination of the bulk viscosity of liquids, based on the absorption of ultrasonic waves, is developed and implemented.The focus is on the simulation-driven design of algorithms for processing the measurement signals as well as the analysis and further development of a measurement set-up based on the pulse-echo method.In addition to absorption in the fluid, there are other effects (for example diffraction or incomplete reflection) that weaken or otherwise influence the acoustic signal.Therefore, the development of procedures to separate these effects from acoustic absorption is another focus of this work.The bulk viscosity is determined from the measured acoustic absorption for different fluids in different thermodynamic states. An uncertainty analysis of the measured quantities concludes this thesis.


      Optimised Multi-Electrode Topology for Piezoelectric Material Characterisation

      L. Claes, N. Feldmann, B. Jurgelucks, V. Schulze, S. Schmidt, A. Walther, B. Henning, 2021, pp. 237-238


      Measurement and Simulation of Lamb Waves in Adhesive-bonded Multilayer Systems

      H. Zeipert, L. Claes, S. Johannesmann, M. Webersen, Y. Lugovtsova, J. Prager, B. Henning, 2021, pp. 91 - 92


      2020

      Analoge Klangsynthese zur Vermittlung von Grundkenntnissen der Signalverarbeitung an Studierende nicht-technischer Fachrichtungen

      M. Krumme, M. Webersen, L. Claes, Y. Webersen, in: Fortschritte der Akustik - DAGA 2020, 2020, pp. 542-545


      Reduction of systematic measurement deviation in acoustic absorption measurement systems

      L. Claes, E. Baumhögger, T. Rüther, .J. Gierse, T. Tröster, B. Henning, in: Fortschritte der Akustik - DAGA 2020, 2020, pp. 1077-1080


      Estimation of acoustic wave non-linearity in ultrasonic measurement systems

      L. Claes, C. Steidl, T. Hetkämper, B. Henning, arXiv.org (2020)


      pyfds 0.1.3 - modular field simulation tool

      L. Claes, M. Webersen. pyfds 0.1.3 - modular field simulation tool. 2020.


      A modular, scalable open-hardware platform for project-based laboratory courses in electrical engineering studies

      T. Hetkämper, M. Krumme, D. Dreiling, L. Claes, in: SEFI 48th Annual Conference Proceedings - Engaging Engineering Education, SEFI, 2020, pp. 1309-1313


      Inverse piezoelectric material parameter characterization using a single disc-shaped specimen

      N. Feldmann, V. Schulze, L. Claes, B. Jurgelucks, A. Walther, B. Henning, tm - Technisches Messen (2020), pp. 50-55

      The increasingly simulation-driven design process of ultrasonic transducers requires several reliable parameters for the description of the material behaviour. Exact results can only be achieved when a single specimen is used in the identification process, which typically is prone to the problem of low sensitivities to certain material parameters and thus high uncertainties. Therefore, a custom electrode topology for increased sensitivity is proposed for a piezoceramic disc. The thereupon conducted measurements of the electric impedance can be used as a starting point for an inverse approach where an equivalent simulation model is used to identify fitting material parameters. An optimisation strategy based on a preliminary sensitivity analysis is presented that leads to a good agreement between measurement and simulation. Furthermore, the proposed measurement procedure is able to evaluate the quality of the simulation model. Hence, different frequency-dependent damping models are presented and evaluated.


        2019

        Quantification of frequency-dependent absorption phenomena

        L. Claes, S. Johannesmann, E. Baumhögger, B. Henning, in: 2019 International Congress on Ultrasonics, 2019


        Evolutionary algorithm for the design of passive electric matching networks for ultrasonic transducers

        T. Hetkämper, L. Claes, B. Henning, in: 2019 International Congress on Ultrasonics, 2019


        Characterization of the linear-acoustic material behavior of fiber-reinforced composites using lamb waves

        S. Johannesmann, M. Webersen, J. Düchting, L. Claes, B. Henning, in: 45th Annual Review of Progress in Quantitative Nondestructive Evaluation , 2019


        Acoustic absorption measurement for the determination of the volume viscosity of pure fluids / Messverfahren für die akustischen Absorption zur Bestimmung der Volumenviskosität reiner Fluide

        L. Claes, L.M. Hülskämper, E. Baumhögger, N. Feldmann, R.S. Chatwell, J. Vrabec, B. Henning, tm - Technisches Messen (2019), pp. 2-6


        Arbitrary sensitivity for inverse problems in piezoelectricity

        B. Jurgelucks, V. Schulze, N. Feldmann, L. Claes, 2019


        A sensitivity-based optimisation procedure for the characterisation of piezoelectric discs

        N. Feldmann, B. Jurgelucks, L. Claes, B. Henning, in: 2019 International Congress on Ultrasonics, 2019


        2018

        Guided ultrasonic waves for determining effective orthotropic material parameters of continuous-fiber reinforced thermoplastic plates

        M. Webersen, S. Johannesmann, J. Düchting, L. Claes, B. Henning, Ultrasonics (2018), 84, pp. 53-62


        Einfluss mechanischer Vorspannung auf das mechanische Materialverhalten von Polymeren

        M. Webersen, S. Johannesmann, T. Brockschmidt, F. Rump, L. Claes, B. Henning, 2018


        Akustische Charakterisierung der richtungsabhängigen elastischen Eigenschaften faserverstärkter Kunststoffe

        M. Webersen, S. Johannesmann, J. Düchting, L. Claes, B. Henning, in: Fortschritte der Akustik - DAGA 2018, 2018, pp. 1263-1266


        An inverse approach to the characterisation of material parameters of piezoelectric discs with triple-ring-electrodes

        N. Feldmann, B. Jurgelucks, L. Claes, V. Schulze, B. Henning, A. Walther, tm - Technisches Messen (2018), 86(2), pp. 59-65


        An acoustic waveguide-based approach to the complete characterisation of linear elastic, orthotropic material behaviour

        S. Johannesmann, J. Düchting, M. Webersen, L. Claes, B. Henning, tm - Technisches Messen (2018), 2018(85), pp. 478-486



        Acoustic material characterization of prestressed, plate-shaped specimens

        S. Johannesmann, T. Brockschmidt, F. Rump, M. Webersen, L. Claes, B. Henning, in: Sensoren und Messsysteme, VDE Verlag GmbH, 2018, pp. 231-234


        Additiv gefertigte, akustische Diffusor-Strukturen für Ultraschallanwendungen

        L. Claes, H. Zeipert, P. Koppa, T. Tröster, B. Henning, 2018


        Optimization of triple-ring electrodes on piezoceramic transducers using algorithmic differentiation

        B. Jurgelucks, L. Claes, A. Walther, B. Henning, Optimization Methods and Software (2018), pp. 1-21


        Vollständige Charakterisierung von piezoelektrischen Scheiben mit Ringelektroden

        N. Feldmann, B. Jurgelucks, L. Claes, B. Henning, 2018


        2017

        Evaluating the Influence of 3D-Printing Parameters on Acoustic Material Properties

        A. Jäger, S. Johannesmann, L. Claes, M. Webersen, B. Henning, M. Kupnik, in: 2017 IEEE IUS~Proceedings, 2017


        Material parameter determination of a piezoelectric disc with triple-ring-electrodes for increased sensitivity

        B. Jurgelucks, N. Feldmann, L. Claes, B. Henning, A. Walther, in: Proceedings of Meetings on Acoustics, 2017, pp. 030010



        Inverser Ansatz zur akustischen Charakterisierung plattenförmiger Materialproben

        S. Johannesmann, L. Claes, M. Webersen, B. Henning, in: Fortschritte der Akustik - DAGA 2017, Deutsche Gesellschaft für Akustik e.V. 2017, 2017, pp. 999-1002


        Additively manufactured acoustic diffuser structures for ultrasonic measurement applications

        L. Claes, H. Zeipert, P. Koppa, T. Tröster, B. Henning, in: Proceedings of Meetings on Acoustics, 2017, pp. 030004


        A Spectral Approach to Acoustic Absorption Measurement

        L. Claes, R.S. Chatwell, J. Vrabec, B. Henning, in: PROCEEDINGS -- AMA Conferences 2017, AMA Service GmbH, 2017, pp. 304-309


        Ultrasonic measurements in the characterization of viscoelasticity and aging of polymers

        F. Bause, L. Claes, M. Webersen, B. Henning, in: PROCEEDINGS -- AMA Conferences 2017, 2017, pp. 414


        Viskoelastizität und Anisotropie von Kunststoffen: Ultraschallbasierte Methoden zur Materialparameterbestimmung

        F. Bause, L. Claes, M. Webersen, S. Johannesmann, B. Henning, tm - Technisches Messen (2017), 84(3)


        Acoustic Material Characterization of Additively Manufactured Components

        L. Claes, A. Jäger, S. Johannesmann, M. Webersen, M. Kupnik, B. Henning, in: PROCEEDINGS -- AMA Conferences 2017, AMA Service GmbH, 2017, pp. 605-610


        2016

        Determination of the material properties of polymers using laser-generated broadband ultrasound

        L. Claes, T. Meyer, F. Bause, J. Rautenberg, B. Henning, Journal of Sensors and Sensor Systems (2016), 5(1), pp. 187-196


        Ultrasonic transmission measurements in the characterization of viscoelasticity utilizing polymeric waveguides

        F. Bause, J. Rautenberg, N. Feldmann, M. Webersen, L. Claes, H. Gravenkamp, B. Henning, Measurement Science and Technology (2016), 27(10)


        Optimisation of triple-ring-electrodes on piezoceramic transducers using algorithmic differentiation

        B. Jurgelucks, L. Claes, in: AD2016 The 7th International Conference on Algorithmic Differentiation, 2016, pp. 99-102


        Miniaturized all-optical Sound Pressure Sensor

        B. Fischer, L. Claes, in: INTER-NOISE 2016, Deutsche Gesellschaft für Akustik e.V., 2016


        Characterization of Continuous-fiber Reinforced Thermoplastics Using Thermoacoustically Excited Ultrasonic Lamb Waves

        M. Webersen, S. Johannesmann, L. Claes, B. Henning, in: 2016 IEEE IUS~Proceedings, 2016



        2015

        Detection of ultrasonic plate waves using ceramic strip transducers

        L. Claes, F. Bause, J. Rautenberg, B. Henning, in: Proceedings SENSOR 2015, 2015, pp. 775-779


        2014



        Methoden zur Zeit-Frequenz-Analyse bei der Untersuchung dispersionsbehafteter Signale

        F. Bause, J. Rautenberg, N. Feldmann, L. Claes, B. Henning, 2014


        2013

        Influence of angular radiated ultrasound waves on the Schlieren tomogram

        S. Olfert, L. Claes, B. Henning, in: Proceedings of the International Conference on Acoustics, DEGA, 2013, pp. 477-480


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