Lumped model of bending electrostrictive transducers for energy harvesting
Résumé
Electroactive polymers, and more particular dielectric electrostrictive polymers, have been of great interest over the last decade thanks to their flexibility, easy processing, conformability, and relatively low cost. Their application as actuators, sensors, or energy harvesters suits very well to systems that require high strain. In particular, bending devices are an important application field of such materials, especially when dealing with devices subjected to air or liquid flows. Nevertheless, the design of such devices and their associated electrical interface still requires starting from the local aspects of the electrostrictive effect. In order to provide a simple yet efficient design tool, this paper exposes a simple lumped model for electrostrictive dielectric devices working under flexural solicitation. Based on the analysis of the converted energy with respect to the provided energy, it is shown that electrostrictive systems can easily be reduced to a simple spring-mass-damper system with a quadratic dependence to the applied voltage on the mechanical side and to a current source controlled by the applied voltage with a capacitive internal impedance on the electrical side. Experimental measurements carried out to evaluate the mechanical to electrical conversion effect as well as the energy harvesting abilities in such systems also validate the proposed approach. © 2014 AIP Publishing LLC.