Microscopic and Macroscopic Instabilities in Dielectric Composite Actuators

The efficiency of electroactive-based devices can be considerably improved employing composite materials. A critical issue in the development of these materials toward applications is the prediction of their failure mechanisms due to the applied electromechanical loads. We report here some results regarding the homogenization and the stability of multilayered soft dielectrics finitely deformed in plane strain under the effect of an external applied voltage, obeying an extended neo-Hookean free-energy function. The investigated criteria of instability are: i.) pull-in instability, ii.) existence of diffuse modes of bifurcation (microscopic modes), iii.) band-localization (macroscopic modes), and iv.) electric breakdown. It is shown that depending on material properties and loading conditions all criteria can become critical for the investigated composites.