^{1}, Jens Rautenberg

^{1}, Bernd Henning

^{1}and Kshitij Kulshreshtha

^{2}

^{1}University of Paderborn, Measurement Engineering Group, Warburger Strasse 100, 33098 Paderborn, Germany.

^{2}University Paderborn, Institute of Mathematics, Warburger Strasse 100, 33098 Paderborn, Germany.

Piezoceramic materials are widely used in ultrasonic devices. To reduce the development time of piezoelectric sensors or actuators numerical methods like the Finite Element Method (FEM) are often applied (e.g. Lahmer et al. (2008)). Therefore a precise knowledge of the piezoelectric material parameters is required to obtain a realistic simulative representation of the real piezoelectric material behavior. There are several inverse identification methods using a comparison between simulated and measured electrical impedance characteristics in order to determine and to optimize the piezoelectric material parameter set (e.g. Kybartas (2002), Rupitsch (2009)). It was shown that the electrical impedance curve is influenced differently by all these material parameters. For example the electrical impedance is less sensitive to some of the material parameters (e.g. c44E) if the used specimen has symmetrical properties or dimensions (e.g. Rautenberg et al. (2011)). Hence the goal of this work is the modification of the electrode shape in order to increase the influence of all material parameters on the electrical impedance characteristic to get more accurate values for these less sensitive and therefore critical material parameters. To achieve this goal a variable FEM-model for the piezoceramic disc is used. The influence of the electrode shape on the sensitivity of material parameters on the electrical impedance curve is investigated. An adapted electrode shape is determined to increase the sensitivity of the electrical impedance curve particularly concerning the selected critical material parameters.