True method to analyze electromechanical stability of dielectric elastomers

Abstract: A layer of dielectric elastomer can be voltage actuated to behave as actuators, but needs to avoid the electromechanical instability of excessively thin down accompanied with electric breakdown. We develop a true method to analyze the electromechanical stability of dielectric elastomers by adopting the positive definiteness of the true tangential modulus matrix, and demonstrate that the previous method is only valid for the special case of zero prestress. Our new method is applicable for arbitrary prestress cases including zero prestress, with predictions consistent with available experimental measurements. Our theoretical results demonstrate the significant effects of prestress on critical voltage and critical actuation stretches.