A novel nonlinear dielectric elastomer generator for vibration energy harvesting

Abstract

The recent development of small scale electronics working within an integrated wireless sensor network has led to the massive potential monitoring of human and structure health. Such devices however are often limited by their battery life, thus there is a great need for energy harvesting to increase the lifespan of these devices. This thesis presents a novel vibration energy harvester based upon dielectric elastomers. A number of numerical models and device setups are investigated, where the device was subjected to a wide variety of harmonic excitation conditions as well as random vibrations. The numerical model was developed through experimentation to determine the nonlinear material properties of a commonly used material, V HBTM 4910. This allowed the device to be compared favourably against other energy harvesters of similar volume. The proposed device is capable of producing a maximum energy density of 9.15J/kg at an excitation frequency of 35Hz. Although observations made regarding the influence of the material nonlinearity have predicted that with a slight increase in the material nonlinearity, the device could significantly increase its energy density to 4359J/kg which would occur at the extremely useful frequency of 3Hz. The creation of this numerical model to simulate an energy harvester also allowed the direct comparison between a promising new electrical scheme and a well developed conventional scheme. Specific investigations were carried out on the device size and orientation, which highlighted an extremely effective setup which can harvest energy from a wide range of excitation conditions and orientations.