Piezoelectric materials are used for various sensor and actuator purposes. Especially in power acoustic applications piezoceramics are loaded with electrical DC voltage or mechanical pre-load, in addition to the excitation signal. Due to the lack of knowledge of material parameters for piezoceramics, particularly in this operating mode, the design of a power transducer is demanding and often strongly empirically driven. A simulation-supported design process requires that a non-linear model for

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... he piezoelectric material behaviour is known. A first step towards this material model is the description of linear approximated material properties in different operating points. To shift this operating point a DC bias voltage is applied to various piezoelectric discs and the frequency dependent impedance is determined. The results indicate a shift of all characteristic resonance frequencies as well as changes of piezoelectric parameters directly dependent on the applied bias voltages.