Design and experimental validation of an exponentially tapering width rotational piezoelectric vibration energy harvester

The efficiency of any rotational piezoelectric vibration energy harvester (RVEH) can be improved by redesigning its host beam and making provision for self-tuning the harvester's natural frequency with the rotational driving frequency. This article presents the design and analysis of an exponentially tapering width RVEH. The parameters for the proposed harvester's natural frequency characteristics are acknowledged, and their effects on the peak open-circuit (OC) voltage response are discussed. A mathematical model of the system is formulated using the Euler-Bernoulli beam theory and Hamilton's principle. Galerkin's technique is used to acquire the system's mass normalized mode shapes in matrix form. The proposed mathematical model is verified through ANSYS Mechanical APDL simulations and experimental methods. The harvester's responses are obtained through MATLAB code. The two types of parameters that modify the harvester's fundamental frequency are identified and analyzed. The proposed harvester delivered an improved power density (PD) of 5.27 mu W mm(-3) and a performance amplification factor (PAF) of 3.14, operating at 7.968 Hz.