Loading system mechanism for dielectric elastomer generators with equi-biaxial state of deformation

... Proceedings of SPIE - The International Society for Optical Engineering Volume 9056, 2014, Article number 90561F Electroactive Polymer Actuators and Devices, EAPAD 2014; San Diego, CA; United States; 10 March 2014 through 13 March 2014; Code 106848 Loading system mechanism for dielectric elastomer generators with equi-biaxial state of deformation (Conference Paper) Fontana, M. , Moretti, G., Lenzo, B., Vertechy, R. PERCRO SEES, TeCIP Institute, Scuola Superiore sant'Anna, Piazza Martiri della Libertà 33, Pisa, 5612, Italy View references (18) Abstract Dielectric Elastomer Generators (DEGs) are devices that employ a cyclically variable membrane capacitor to produce electricity from oscillating sources of mechanical energy. Capacitance variation is obtained thanks to the use of dielectric and conductive layers that can undergo different states of deformation including: uniform or non-uniform and uni- or multi-axial stretching. Among them, uniform equi-biaxial stretching is reputed as being the most effective state of deformation that maximizes the amount of energy that can be extracted in a cycle by a unit volume of Dielectric Elastomer (DE) material. This paper presents a DEG concept, with linear input motion and tunable impedance, that is based on a mechanical loading system for inducing uniform equi-biaxial states of deformation. The presented system employs two circular DE membrane capacitors that are arranged in an agonist-antagonist configuration. An analytical model of the overall system is developed and used to find the optimal design parameters that make it possible to tune the elastic response of the generator over the range of motion of interest. An apparatus is developed for the equi-biaxial testing of DE membranes and used for the experimental verification of the employed numerical models.