Study on the gel effect on dielectric elastomer actuators

• Main Author: Foong, Ervin Sheng Wei
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/60274
• Institution: Nanyang Technological University

Dielectric elastomer actuators (DEAs), whose mode of actuation depends on converting electrical energy to mechanical energy using electrostatic pressure, have shown the potential for various applications due to their weight and simplicity. Due to their current limitations, they have not seen widespread use. A notable one would be their low actuation force, and much research has been carried out in an attempt to overcome this. One approach would be to stack the DEAs to upscale their performance. Another approach taken was to improve the maximum electric field strength a DEA is able to sustain, since DEAs rely on electrostatic pressure for their actuation. To that extent, La et al. has shown that by immersing DEA in dielectric oil, the DEA was able to avoid premature breakdown and sustain up to two times the maximum electric field strength. As there are various complications involved in stacking the DEAs with oil immersion, a motivation for this project would be to investigate if the usage of dielectric gel would be able to replicate the effects of dielectric oil. The initial part of this project investigated the resistance of the electrodes of the DEA with and without gel coating at various strain rates. Effects on the electrodes are important as they are a main factor of actuation on a DEA. It was found that the resistance did increase significantly with the coating than without. This change in resistance is notable as it could affect the actuation of the DEA adversely. The following section investigates the effects of the gel as a whole on the DEA. It shows that a coating of dielectric gel was able to avert premature breakdown and improve the dielectric strength as well. It also shows that the coating can also be applied to double-layered DEAs, while receiving the same effects as well. However, the use of gel also entailed a reduction to actuation performance. This was hypothesised to be due to added stiffness and raised resistance from the electrode due to the gel coating. Another effect observed was an apparent self-recovery mechanism which enabled the DEA to remain functional after a partial breakdown had occurred.