In-Plane Field Propagation in EAP Transducers Based on the Equivalent Network Method

Dielectric Electroactive Polymers belong to a new class of smart materials, whose functional principle is based on electrostatic forces. They can either be used as actuators to provide considerable stretch ratios or as generators to convert mechanical strain energy into electrical energy by use of an initial amount of energy. Since the polymer material and also the covering compliant electrodes show non-ideal electrical properties, like finite resistivity and conductivity respectively, design rules have to be derived, in order to optimize the devices. The electrode conductivity in connection with the polymer resistivity causes a voltage drop along the electrode surface, resulting in a reduced actuation strain or energy conversion. To minimize its parasitic effects, the influence of this effect is studied by the in-plane field propagation based on a model obtained with the equivalent network method. It is shown that the proposed model provides accurate results, which can be used to study the effect of contacting electrodes, especially in case of point contacts.