Investigation of local strains in circular dielectric elastomer actuators

Dielectric elastomer actuators (DEAs) are a class of soft actuators capable of large deformations when electrically activated. Their performance is influenced by factors such as pre-stretch, boundary conditions, and the ratio of active to passive areas. Conventional strain assessment methods often rely on global measurements, assuming uniform strain distributions, which limits the ability to analyze localized deformations. In this study, digital image correlation (DIC) was applied to characterize the in-plane strain field of a circular DEA. By evaluating radial and tangential strain distributions in both active and passive regions, a more detailed understanding of the actuator’s deformation behavior was achieved. The results show a homogeneous equi-biaxial expansion of the active region and a non-uniform strain distribution in the passive area, with radial compression and tangential expansion. The comparison with existing models shows good qualitative agreement and confirms the effectiveness of DIC for detailed strain analysis. This method enhances the accuracy of DEA characterization and supports the development of improved modeling approaches for future applications.