Finite element analysis of piezoelectric cantilever beam using vibration for energy harvesting devices

This paper presents the design and analysis of a piezoelectric cantilever beam with tip mass under ambient mechanical vibration energy source. The ambient mechanical vibration energy generates stress and strain in the piezoelectric materials, which is converted into electrical energy by the principle of piezoelectric effect. The generated energy can be used for low power electronic devices. The geometry of the cantilever beam structure was designed by using SolidWorks. The structure consists of a bimorph piezoelectric layer, Aluminium substrate, and a tungsten proof mass. The cantilever beam was simulated using the Finite Element Method (FEM) in COMSOL Multiphysics. During FEM simulation, a vibration source of 1g acceleration was applied on the beam. As a result, the maximum displacement of the beam was obtained 2.4 µm at a resonant frequency of 192.25 Hz. Stress generation on the beam was analyzed because the piezoelectric energy harvesting from vibration depends on stress generation in piezoelectric materials. The maximum amount of stress was found 1.11×105 N/m2 at the clamped end of the beam during resonance. A voltage output of 4.4mV has been obtained from the harvester. The designed beam can be operated in low-frequency ambient vibration sources.