Test and Analysis of Bridge Transducers for Harvesting Energy from Asphalt Pavement

Abstract

Part of energies in asphalt pavement caused by vehicle can be converted into electric energy by piezoelectric transducer. A bridge-shaped transducer is selected to harvest energy because of its reasonable efficiency and moderate stiffness close to asphalt pavement. This paper is to compare the performance of Bridge transducers with trapezoidal, arc and arch structure through finite element analysis (FEA) and laboratory test. Results show that the arch Bridge has higher energy conversion efficiency and the trapezoidal Bridge has stronger ability to resist pressure. For arc and trapezoidal Bridge, the maximum tensile stress and shear stress are both in the inner corner of contact area between cap and PZT (lead zirconate titanate) disk. They were broken because of the cracking of PZT at the stress concentrations area. For arch Bridge, the maximum tensile stress increases with thickness of metal cap but decrease with modulus, and maximum shear stress decreases first and increases later with increasing thickness and modulus of metal cap. In laboratory test, its cracking area is shifted from edge to inner corner of contact area between cap and PZT disk with increasing thickness of metal cap. The electric potential generated by arch Bridge decreased with increasing thickness and modulus of metal cap. Under the load of 0.7 MPa, the electric potential is about 286 V for an arch Bridge transducer with 0.4mm thickness of stainless steel cap, and its storage electric energy is 0.6 mJ. The designed arch Bridge transducer is suggested as the optimum one for harvesting energy from asphalt pavement