An experimental investigation of the dielectric elastomer generator with equi-biaxial stretching

Abstract

This project focuses on the effect of using equi-biaxial stretching on the voltage increase of a dielectric elastomer generator, experiments and tests were carried out at various initial voltage supply and the voltage increase was recorded for every interval decrease in the dimension of the membrane. The data collected was plotted on graphs to analyze the trends and pattern and to verify if the stretching of the membrane causes the capacitance to increase with the fourth power of the stretch, or conversely, whether the voltage would increase with the fourth power of stretch when the membrane relaxes.

The findings in this project have shown that the experimental data do not match the theoretical data calculated from the equations of capacitance of a dielectric film. The theoretical data shows an exponential increase in the voltage when the membrane is relaxed whereas the experimental data shows a more linear increase, the theoretical data also has a maximum voltage of 4-6 times that of the maximum voltage for the experimental data. The cause of this will be discussed in Chapter 4 of this paper.

A large bulk of time was spent coming up with the design and concept for the stretching board which had to go through many rounds of modification before it could be user-friendlier and achieve equi-biaxial stretch. The fabrication process had to be modified from the uniaxial stretch in Zeng Geng’s report as there were many complications that arose from the use of an equi-biaxial stretcher. Another issue faced was that the voltage reading on the voltmeter is always higher compared to the voltage shown on the power supply whenever the probe is reading off the surface of the dielectric elastomer, this will be discussed in Chapter 4 of this paper.

After completion of this project, there is still room for improvement in the future such as energy harvesting with capacitors, testing with different electrode materials such as carbon grease or crushed silver and also using a voltage monitoring software to achieve more accurate and precise data acquisition.