A high density piezoelectric energy harvesting device from highway traffic – Design analysis and laboratory validation

Abstract

This paper introduces an innovative piezoelectric energy harvesting device with a high density of the energy harvested from highway traffic. The piezoelectric energy harvesting device has a compression-to-compression force amplification mechanism provided by clamped-clamped nonlinear elastic beams. The amplification mechanism enables the device to fully explore the power conversion potential of the piezoelectric material and can deliver the harvested electricity far more than that generated by the same piezoelectric material under direct compressive loading without amplification. For example, when the amplification factor is equal to 10, the generated electricity is nearly 100 times bigger. A multi-objective optimal design problem of the piezoelectric energy harvesting device is formulated. A set of multi-objective optimal designs has been found numerically in the parameter space. The paper presents the analysis of the nonlinear beams and a finite element model of multi-layer piezoelectric ceramic stacks. Impulsive time dynamic loadings from the passing vehicles are considered. The dynamic response of the piezoelectric energy harvesting device to the impulsive traffic loadings is investigated. The laboratory test results are presented to validate the mathematical model and mechanical design of the device. In a quasi-static load cycle of 1333N, a preloaded piezoelectric energy harvesting device prototype (142×42×84mm3) is able to generate a voltage of 128V and a potential electric energy of 120mJ while the sinking displacement is 2.54mm. Numerical results of the dynamic response show that the piezoelectric energy harvesting device performs well over a wide range of vehicle speed from 8.05 to 128.75 km/h. High speed seems beneficial to energy harvesting.