Energy harvesting from mechanical vibrations using piezoelectric cantilever beams

In this paper, a design methodology for an energy harvesting device will be investigated and results will be presented to validate the design. The energy harvesting device in the study is 31-unimorph piezoelectric cantilever beam which was used to convert small amplitude mechanical vibration from a specific machine application into an electrical energy source that could be used for electronic devices with low power requirements. The primary purpose of the design methodology is to illustrate a method to design a cantilever beam that is optimized for a particular application. The methodology will show how the vibration data (frequency and amplitude) from the machine was analyzed and then how this information was incorporated into the final design of the beam. From the given vibration data a range of frequencies where the energy harvesting device will generate the greatest amount of energy is determined. The device is then designed specifically targeting that frequency range. This approach is presented as part of a more general approach to designing energy harvesters for any application. Also, it will be shown how the thickness and type of materials used for each layer of cantilever beam were chosen, completely independent of the vibration data, without effecting the over all optimization process.