On the electrode-elastomer patterns in dielectric elastomer actuator motion

Abstract

Owing to their intrinsic actuation capability and outstanding electromechanical characteristics, dielectric elastomer actuators (DEAs) are promising smart materials with the potential to outperform conventional mechanical and electrical actuation systems for certain engineering applications, such as soft robotics and biomedical engineering. As a single-layer, planar DEA produces only one-dimensional deformation, i.e., contraction-expansion, with a moderate actuation force, different actuation mechanisms, such as rolling or stacking DEAs, have been implemented to obtain larger deformations and higher actuation forces. However, these DEA configurations do not alter the fundamental type of thickness-wise deformation. In some applications, DEA’s out-of-plane actuation motion, such as bending, is often desired for effective system operation. Currently, the desired types of DEA deformation are generally attained by implementing additional members or mechanisms using various means, e.g., stiff frames, unimorph or bimorph, multistable structures, preloaded mechanisms. Although the methods above enable DEAs to achieve desired motions, they can considerably constrain deformation and actuation force and mostly require manual assemblies. This paper demonstrates a novel DEA capable of generating the needed range of motions without introducing additional elements within the actuator. This was accomplished by tailoring the electrode-elastomer pattern and thereby deforming the elastomer in the desired manner. Studied DEA design was first developed using theoretical basics about flat capacitors and then verified through finite element analysis. The designed actuator was additively manufactured using a contact microdispensing 3D printer and tested to validate its bending due to the tailored electric field.