Voltage-controlled radial wrinkles of a trumpet-like dielectric elastomer structure

Wrinkle is usually considered as one failure mode of membrane structure. However, it can also be harnessed in developing smart devices such as dry adhesion tape, diffraction grating, smart window, etc. In this paper, we present a method to generate voltage-controlled radial wrinkles, which are fast response and reversible, in a stretched circular dielectric elastomer (DE) membrane with boundary fixed. In the experiment, we bond a circular plate on the center of the circular membrane and then pull the DE membrane perpendicular to itself via the plate. The stretched DE membrane is a trumpet-like structure. When the stretched DE membrane is subjected to a certain voltage, wrinkles nucleate from the center of the DE membrane and propagate to the boundary as the voltage increases. We adopt a theoretical framework to analyze the nucleation of the wrinkles. A simple wavelength expression is achieved, which is only related to the geometry and the stretch of the DE membrane. Results show that the theory agrees well with the experiment. This work may help the future design of DE actuators in avoiding mechanical instability and provide a new method to generate controllable radial DE wrinkles.