Energy Harvesting Using an Array of Granules

In the last decade, there has been an increasing attention on the use of highly and weakly nonlinear solitary waves in engineering and physics. These waves can form and travel in nonlinear systems such as one-dimensional chains of particles. One engineering application of solitary waves is the fabrication of acoustic lenses, which are employed in a variety of fields ranging from biomedical imaging and surgery to defense systems and damage detection. In this paper, we propose to couple an acoustic lens to a wafer-type lead zirconate titanate (PZT) transducer to harvest energy from the vibration of an object tapping the lens. The lens consists of an ordered array of spherical particles in contact with a polycarbonate material where the nonlinear waves become linear and coalesce ideally into a focal point. The transducer located at the designed focal point converts the mechanical energy carried by the stress waves into electricity to power a load resistor. The performance of the designed harvester is compared to a conventional nonoptimized cantilever beam, and the experimental results show that the power generated with the nonlinear lens has the same order of magnitude of the beam.