Modelling piezoelectric modules with interdigitated electrode structures

The Interdigitaded Electrode Design, which allows to utilise the primary piezoelectric effect in longitudinal direction for piezoelectric sheet actuators, is investigated with the help of a detailed finite element analysis. Two different set-ups have been studied, based on (a) a piezoelectric bulk film and (b) a composite with piezoelectric fibres as the piezoelectric active component. The models allow to investigate the influence of various geometrical and material parameters on the deformation performance and on failure hazards due to field concentrations. For the bulk film actuator case, the development of an inhomogeneous poling state from the poling process of the piezoceramic material may be included into the model in an approximate way. For the composite actuator case, special emphasis has been laid on the problem of indirect contact between electrodes and embedded piezoelectric fibres. Specific proposals for the parameter design could be derived, which have been used as a starting point for the practical optimisation process.