Performance of non-uniform cantilever based piezoelectric energy harvester

Abstract

Cantilever based piezoelectric energy harvesters (PEHs) have been optimized in terms of shape, size, material properties and damping to improve their electrical outputs. In most of the PEHs, a cantilever beam with width of rectangular, triangular and trapezoidal shapes, respectively, have been analyzed in optimizing the power output. In this paper, we investigate the influence of non-uniform beams with linearly and quartic varying widths. To analyze the model, we first modify the electromechanical formulation of uni-morph piezoelectric cantilever beam with uniform section to include the non-uniform variation of beam width. Subsequently, we obtain the voltage, current and the power output versus frequencies at different external loads for uniform and non-uniform beams with varying tapering parameters. Based on the analysis, we found that the diverging beam with tapering parameter of 0.6 can produce an enhanced power output by 3833% as compared to that of uniform beam. Since, the frequency also changes due to change in the tapering parameter of non-uniform beam, such significant changes in the output are also demonstrated for designing a wide band PEH based on an array of uniform and non-uniform beams. Finally, we also performed numerical study of PEHs of unimorph as well as coupled beams with uniform and non-uniform sections.