TY - JOUR AU - Claes, Leander AU - Feldmann, Nadine AU - Schulze, Veronika AU - Meihost, Lars AU - Kuhlmann, Henrik AU - Jurgelucks, Benjamin AU - Walther, Andrea AU - Henning, Bernd ID - 45445 IS - 1 JF - Journal of Sensors and Sensor Systems TI - Inverse procedure for measuring piezoelectric material parameters using a single multi-electrode sample VL - 12 ER - TY - CONF AU - Claes, Leander AU - Feldmann, Nadine AU - Schulze, Veronika AU - Jurgelucks, Benjamin AU - Walther, Andrea AU - Henning, Bernd ID - 6553 T2 - Fortschritte der Akustik - DAGA 2022 TI - Identification of piezoelectric material parameters using optimised multi-electrode specimens ER - TY - JOUR AB - 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. AU - Inguva, Venkatesh AU - Feldmann, Nadine AU - Claes, Leander AU - Koturbash, Taras AU - Hahn-Jose, Thomas AU - Koutcherov, Vladimir AU - Kenig, Eugeny ID - 6579 JF - Engineering Reports TI - An explicit symplectic approach to solving the wave equation in moving media ER - TY - GEN AU - Friesen, Olga AU - Claes, Leander AU - Feldmann, Nadine AU - Henning, Bernd ID - 6558 TI - Estimation of piezoelectric material parameters of ring-shaped specimens ER - TY - JOUR AB - 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. AU - Johannesmann, Sarah AU - Claes, Leander AU - Feldmann, Nadine AU - Zeipert, Henning AU - Henning, Bernd ID - 30863 IS - 7 - 8 JF - tm - Technisches Messen KW - Electrical and Electronic Engineering KW - Instrumentation SN - 2196-7113 TI - Lamb wave based approach to the determination of acoustic material parameters VL - 89 ER - TY - JOUR AU - Itner, Dominik AU - Gravenkamp, Hauke AU - Dreiling, Dmitrij AU - Feldmann, Nadine AU - Henning, Bernd ID - 21082 JF - PAMM SN - 1617-7061 TI - Simulation of guided waves in cylinders subject to arbitrary boundary conditions for applications in material characterization ER - TY - GEN AU - Itner, Dominik AU - Gravenkamp, Hauke AU - Dreiling, Dmitrij AU - Feldmann, Nadine AU - Henning, Bernd ID - 21564 TI - On the forward simulation and cost functions for the ultrasonic material characterization of polymers ER - TY - CONF AB - 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. AU - Dreiling, Dmitrij AU - Itner, Dominik AU - Feldmann, Nadine AU - Scheidemann, Claus AU - Gravenkamp, Hauke AU - Henning, Bernd ID - 25265 T2 - Fortschritte der Akustik - DAGA 2021 TI - Application and modelling of ultrasonic transducers using 1-3 piezoelectric composites with structured electrodes ER - TY - GEN AU - Schulze, Veronika AU - Schmidt, Stephan AU - Jurgelucks, Benjamin AU - Feldmann, Nadine AU - Claes, Leander ID - 21233 TI - Optimal experiment design with respect to electrode configurations for a piezoelectric problem ER - TY - JOUR AB - 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. AU - Feldmann, Nadine AU - Schulze, Veronika AU - Claes, Leander AU - Jurgelucks, Benjamin AU - Meihost, Lars AU - Walther, Andrea AU - Henning, Bernd ID - 21341 IS - 5 JF - tm - Technisches Messen SN - 2196-7113 TI - Modelling damping in piezoceramics: A comparative study VL - 88 ER - TY - CONF AU - Claes, Leander AU - Feldmann, Nadine AU - Jurgelucks, Benjamin AU - Schulze, Veronika AU - Schmidt, Stephan AU - Walther, Andrea AU - Henning, Bernd ID - 22012 TI - Optimised Multi-Electrode Topology for Piezoelectric Material Characterisation ER - TY - GEN AU - Schulze, Veronika AU - Schmidt, Stephan AU - Jurgelucks, Benjamin AU - Feldmann, Nadine AU - Claes, Leander ID - 23462 TI - Piezoelectric BC Modeling for Electrode Shapes with OED ER - TY - CONF AU - Itner, D. AU - Gravenkamp, H. AU - Dreiling, Dmitrij AU - Feldmann, Nadine AU - Henning, Bernd ID - 40541 T2 - 14th WCCM-ECCOMAS Congress TI - Simulation of Guided Waves in Cylinders Subject to Arbitrary Boundary Conditions Using the Scaled Boundary Finite Element Method VL - 700 ER - TY - JOUR AU - Itner, Dominik AU - Gravenkamp, Hauke AU - Dreiling, Dmitrij AU - Feldmann, Nadine AU - Henning, Bernd ID - 21232 JF - Ultrasonics SN - 0041-624X TI - Efficient semi-analytical simulation of elastic guided waves in cylinders subject to arbitrary non-symmetric loads ER - TY - THES AB - 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. AU - Feldmann, Nadine ID - 6563 TI - Ein modellbasiertes Messverfahren zur Charakterisierung von Piezokeramiken unter Verwendung eines einzelnen scheibenförmigen Probekörpers ER - TY - CONF AU - Dreiling, Dmitrij AU - Itner, Dominik Thor AU - Feldmann, Nadine AU - Gravenkamp, Hauke AU - Henning, Bernd ID - 17089 TI - Increasing the sensitivity in the determination of material parameters by using arbitrary loads in ultrasonic transmission measurements ER - TY - CONF AU - Feldmann, Nadine AU - Schulze, Veronika AU - Jurgelucks, Benjamin AU - Henning, Bernd ID - 15163 T2 - Fortschritte der Akustik - DAGA 2020 TI - Solving piezoelectric inverse problems using Algorithmic Differentiation ER - TY - JOUR AB - 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. AU - Feldmann, Nadine AU - Schulze, Veronika AU - Claes, Leander AU - Jurgelucks, Benjamin AU - Walther, Andrea AU - Henning, Bernd ID - 19313 JF - tm - Technisches Messen SN - 2196-7113 TI - Inverse piezoelectric material parameter characterization using a single disc-shaped specimen ER - TY - CONF AU - Feldmann, Nadine AU - Jurgelucks, Benjamin AU - Claes, Leander AU - Henning, Bernd ID - 15164 T2 - 2019 International Congress on Ultrasonics TI - A sensitivity-based optimisation procedure for the characterisation of piezoelectric discs ER - TY - JOUR AU - Claes, Leander AU - Hülskämper, Lars Moritz AU - Baumhögger, Elmar AU - Feldmann, Nadine AU - Chatwell, René Spencer AU - Vrabec, Jadran AU - Henning, Bernd ID - 13143 JF - tm - Technisches Messen SN - 2196-7113 TI - Acoustic absorption measurement for the determination of the volume viscosity of pure fluids / Messverfahren für die akustischen Absorption zur Bestimmung der Volumenviskosität reiner Fluide ER -