Modeling and simulation of compliant biasing systems for dielectric elastomer membranes based on polymeric domes

Due to their large deformation, high flexibility, and lightweight, dielectric elastomer actuators (DEAs) represent a promising alternative technology for the design of miniaturized drive systems. In order to generate a stroke, a membrane DEA needs to be preloaded with a mechanical bias elements. The use of negative-rate biasing systems (NBS), such as buckled beams or permanent magnets, permits to significantly increase the resulting DEA stroke in comparison to conventional linear springs. This paper focuses on a novel type of NBS element for DEAs, consisting of compliant polymer domes. Advantages of the compliant domes over a rigid NBS include large mechanical flexibility in conjunction with high potential for miniaturization. A physics-based model of the dome is first developed and implemented in a finite element simulation environment. The model is subsequently calibrated and validated via experimental data. A design algorithm is finally developed to determine the biasing system geometry which maximizes the actuator stroke, based on the knowledge of the dome material parameters as well as the electro-mechanical DEA characteristics.