Proof mass effect on piezoelectric cantilever beam for vibrational energy harvesting using Finite Element Method

Abstract

Energy harvesting is a process of extracting and converting ambient energy into electrical energy. Ambient vibration energy can be utilised by electromagnetic, electrostatic and piezoelectric mechanisms to provide electrical energy. Piezoelectric mechanism is widely preferred due its effective piezoelectric effect. Resonant frequency of structure is a vital parameter in piezoelectric energy harvesting. In this paper, proof mass effect on piezoelectric cantilever beams was analysed to reduce resonant frequency. The structure of the beams were designed in SolidWorks. The beams were consisted of bi-layered PZT-5H, Aluminium substrate and Tungsten proof mass. The dimensions of proof mass were varied only. The other parts were remain unchanged in dimensions. The beams were analysed by using Finite Element Method (FEM) in COMSOL Multiphysics. Vibration acceleration of 1 g (g = 9.81 m/s2) was applied on both beams. Higher terminal voltage of 7.8 mV was obtained at lower resonant frequency of 163.4 Hz from the beam with larger proof mass. While from the other beam with smaller proof mass, terminal voltage of 7.64 mV was obtained at higher resonant frequency of 190.3 Hz. The designed and analysed beams can be used for wireless sensor networks, monitoring structures, temperature and humidity sensors etc.