Vibration-based energy harvesting has been investigated by several researchers over the last ten years. The goal is to power small electronic components by converting the waste mechanical energy available in their environment into electrical energy. Also, the concept of energy harvesting is useful for remotely operated systems with limited energy sources. Recent literature shows that piezoelectric transduction has received the most attention for vibration-to electricity conversion. In practice, cantilevered beams and plates with piezoceramic layers are employed as piezoelectric energy harvesters. Changing the shape of the beam to concentrate the strain in sections of the beam where it can contribute the most to transduction. The motivation is that the strain is not constant along the length of a piezoelectric bimorph. However, the electric field across the piezoelectric layers is proportional to axial strain. By arranging the beam so that there is more piezoelectric material where there is more strain, and removing material from where there is less strain, the overall coupling of the beam can be increased. This proposal presents the modeling and analysis of piezoelectric energy harvesters with varying cross-sectional area and a tip mass. The Euler-Bernoulli beam model is assumed and the Rayleigh-Ritz approach used to model the transverse vibrations. Different beam's shape will be investigated in order to obtain the optimum one (among the ones considered in this work).
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