Abstract: During the working process of a dielectric electroactive polymer (EAP) actuator, variations of boundary conditions and actuation voltages often lead to wrinkling and dielectric breakdown of the EAP membrane and result in the failure of the actuator. To avoid this and assure the safety of the actuator, its failure behavior is investigated. The deformation is obtained of the EAP membrane of a conically-shaped dielectric EAP actuator, together with the distribution of its principal stress, the principal stretch ratio and electrical field in the membrane under different voltages, This is used to predict the failure of a dielectric EAP actuator based on the failure criterion of the membrane. How the prestretch ratio of an EAP membrane affects the failure of the actuator is also explored. Finally, the experiment results of the critical wrinkle voltage of the EAP actuator agree well with the theoretical analysis, and the experiments show that prestretch can improve the electromechanical stability of an EAP membrane. The work of this paper can be used to predict the critical voltage of a dielectric EAP actuator when the failure occurs and guarantee its safe working.

Key words: dielectric electroactive polymer, actuators, failure, wrinkling, dielectric breakdown