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Towards Actuation Improvement of Low-profile Piezo Fibre Composites by Notched Electrodes

: Hohlfeld, Kai; Neumeister, Peter; Michaelis, Alexander; Gebhardt, Sylvia


Sensors and Actuators. A 291 (2019), pp.32-38
ISSN: 0924-4247
Deutsche Forschungsgemeinschaft DFG
SFB/TR 39 PT-PIESA; Teilprojekt A01
Fertigungstechnologien für integrierbare piezoelektrische Funktionskomponenten
Journal Article
Fraunhofer IKTS ()
actuator; PZT fibre; piezo fibre composite; low-profile patch transducer; poling simulation

The present contribution reports on a novel approach for enhanced piezoelectric patch transducers based on round piezoceramic fibres. Starting from a critical review of the well-known Active Fibre Composite (AFC) concerning electrical coupling between electrodes and ceramic fibres, a new electrode design is proposed. By introducing notches into the fibres perpendicular to their axis and filling these notches witch a conductor, a much better coupling is created. This leads to a significantly better alignment of the intrinsic dipoles over a wide volume of the fibres during poling and thus to much higher piezoelectric performance of the transducers. With the aid of a finite element analyses, design rules for optimization of notched electrodes as well as prediction of transducer behaviour have been derived. For verification of the approach, transducers with varying notch depths have been built and glued onto polystyrene beams attaining active cantilevers. The setup was used to measure free displacement and blocking force generated by the transducers in comparison to other existing patch transducers. An improvement of the piezoelectric actuation up to a factor of four is observed for free deflection and blocking force, significantly exceeding results from state-of-the-art patch transducers such as Macro Fiber Composites (MFC).