Out of plane actuator concept and characterization of dielectric elastomer EAP materials

A biaxial pre-stretching of an elastomer film providing a negative load is an effective method in enhancing the actuating properties in electromechanical applications. The pre-stretching can be implemented by rolling an elastomer sheet around a compressed spring or by framing a stretched film using a rigid or a soft frame. One of the best known commercial dielectric elastomer materials is based on acrylic elastomers, e.g. 3M VHB 4910 or 4905 adhesive tape. In this work the VHB 49 10 tape was used for the out of plane actuators. The 3M tape was framed using a soft frame, which enabled an out of plane actuator movement of 180 degrees and a force of at least 30 mN. The used voltages were between 4 and 8 kV and the film thickness around 100 mu m. The actuator was also used to make two simple application tests: a walker and a lifter. Current-voltage characterization was used to study the energy efficiency, frequency dependent behavior, and to develop a model for hyper elastic material properties.