Performance enhancement of cantilever piezoelectric energy harvesters by sizing analysis

This paper presents the results of the performance of piezoelectric cantilever beams in relation to their size. The total produced power represents the main indicator of performance of a piezoelectric harvesting system while the area of the beams stays constant. Lightweight design is an important aspect in any industry, mainly in the aerospace. In this study, the effects of non-uniformity on the efficiency and power output are studied. Finite element method (FEM) with the application of superconvergent element (SCE) is adopted here to solve the equations. It is observed that the trapezoidal geometry (converging beam) provides a higher output power while the efficiency decreases. Moreover, in order to prove that the power enhancement is achievable while the amount of piezoelectric material consumed is constant the new configuration is proposed. In the configuration, an array of uniform beams connected in series is used instead of one single rectangular beam. The proposed setting generates an output power of 1.817 mW at a resonant frequency of 284.6 Hz when excited by an input acceleration of 1 g. The only challenge is the fundamental frequency difference which is met with the application of proof mass and thinner substrate and piezoelectric layers.