Energy harvesting using piezoelectric materials

In this study, design aspects of piezoelectric energy harvesters (PEHs) used for generating energy from mechanical vibrations were addressed. Initially, high energy density piezoelectric ceramics were produced. The phase formation was characterized using X-ray diffraction and the processing parameters for elimination of the pyrochlore phase which is detrimental to piezoelectric properties were searched. Microstructure of the samples were inspected using SEM images. Secondly, to reduce the resonance frequencies of the transducers, for a better matching with the vibration frequencies of human made structures, a novel metallic beam structure was modeled. The mathematical model of the structure was constructed using the Euler-Bernoulli beam theory and the finite element model was built with ANSYS code. The change in resonance frequency depending on the thickness of the beam, the length of the beam and the tip mass attached to the beam was computed. As a further step forward, the energy harvesting performances of cymbal transducers were evaluated. Finally, the cymbal transducers were attached to the metallic energy harvesting structure to form the PEH. The power output of the transducers were calculated for varying frequencies and changing tip mass.