An Analysis of the Aerodynamic Response of an Electroactive Membrane

Dielectric elastomer membranes are a category of electroactive polymers composed of a thin elastomer film sandwiched between two compliant electrodes. An electrostatic pressure is created when there is an externally applied voltage on the electrodes which creates compression in the thickness direction and extension in the in-plane direction. This outlines a variation of the tension in the membrane that can be used to change its dynamic behavior. In this study, a specimen of an electroactive membrane, VHB 4910 is considered to observe the aerodynamic characteristics under external flow of air. Both experimental and numerical analyses are performed to predict the fluid-structure interaction behavior of the specimen for different angles of attack. A vibration testing arrangement is used to estimate the resonance frequencies and the mode shapes which are validated by the finite element results. From the study, the coefficient of lift is found to increase with the angle of attack up to a critical value. Similarly, the coefficient of drag increases with the angle of attack. Both lift and drag coefficients decrease with the Reynolds number. The magnitudes of the natural frequencies decrease as the applied voltages rise. The natural frequencies and mode shapes of the membrane can be tuned by changing the pretension, the pressure, and/or the voltage.