Electromechanical characterization and measurement protocol for dielectric elastomer actuators

Dielectric elastomer actuators (DEA) considerably change shape when stimulated electrically and hold promise as artificial muscles. An electromechanical characterization protocol for DEA's is developed and tested with the VHB 4910 polyacrylic elastomer from 3M, where the current - voltage response of the actuator is recorded together with the area expansion from a video-extensometer until breakdown occurs. The current is a direct measure of the area expansion of the DEA and can be used to control the actuator. The modeling of the DEA is based on hyperelasticity models for elastomers. Minimum requirements for the strain energy function of dielectric elastomers are derived in terms of the principal stretching ratios guaranteeing stability against mechanical collapse of the actuator. The electromechanical characterization and modeling protocol developed may provide useful guidelines for the selection and assessment of new dielectric elastomer materials.