Finite element analysis of Cymbal piezoelectric transducers for harvesting energy from asphalt pavement

Abstract

The purpose of this paper is to design a Cymbal for harvesting energy from asphalt pavement. Asphalt pavement is used popular on road. Part of the energies in the pavement caused by vehicle and gravity can be harvested by piezoelectric transducers. Cymbal is selected to harvest energy from asphalt pavement because of its low cost, high reliability and reasonable efficiency. The efficiency and coupling effects with pavement of Cymbals with various sizes are discussed through finite element analysis (FEA). The displacement difference at pavement surface between with and without Cymbal is developed to considering the coupling effects. The results show that the potential electric energy harvested from pavement increases with the diameter of Cymbal. However, the efficiency decreases with the increasing of Cymbal size. The diameter at 32mm is suggested as the size of Cymbal. The potential electric energy increases near linearly with the diameter of end cap cavity base. Enough bonding area should be left to bond the end steel cap and PZT. There is a maximum electric energy existing when the top diameter of the end steel cap changes. The maximum electric energy is generated when the thickness of cap steel is about 0.3 mm. There is also a maximum electric energy existing when the height of end cap cavity changes. The Cymbals with thicker PZT can generate higher electric potential and storage electric energy. Considering the storage electric energy, cost, bonding between end steel cap and PZT and the pavement surface displacement, the Cymbal with 32mm of total diameter, 22mm of cavity base diameter, 10mm of end cap top diameter, 0.3mm of cap steel thickness, 2 mm of cavity height and 2mm of PZT thickness is suggested as the optimum one for harvesting energy from asphalt pavement. The electric potential is about 97.33V of the design Cymbal. 0.06J electric energy can be storage in that Cymbal. Its potential maximum output power is about 1.2mW at 20Hz vehicle load frequency. © 2010 The Ceramic Society of Japan. All rights reserved.