An effective energy harvesting in low frequency using a piezo-patch cantilever beam with tapered rectangular cavities

This work presents a novel geometric structure of cantilevered beam based energy harvesters to achieve high power in low operating frequency range. The proposed harvester consists of tapered section with rectangular cavity beam (TSRCB). An analytical model is formulated using Euler-Bernoulli beam theory, and its solution is acquired by Bessel functions. A semi-analytical deflection function is assumed to find the natural frequencies of the proposed harvester using Rayleigh-Ritz method. Comprehensive parametric studies for natural frequencies of the proposed harvester are then analyzed using COMSOL Multiphysics to find the uniform stress distribution across the piezoelectric patch. The inclusion of rectangular cavity at tapered and rectangular section affects the output voltage due to the shift in the neutral axis position of the proposed harvester. It is shown that TSRCB harvester featuring the rectangular cavity at tapered section provides higher power than the uniform piezoelectric beam when the beam is subject to input force attained from low frequency excitation by an electromagnetic exciter. In addition, it is demonstrated that the results attained from the analytical model and numerical simulation are in close with the experimentation validating the effectiveness of the proposed analytical model. (C) 2019 Elsevier B.V. All rights reserved.