Nonlinear Physics-based Modeling of a Piezoelectric Energy Harvester

Piezoelectric vibration-based energy harvesting has received great attention over the past decade. Because of the significant influence on the amount of generated power, several research efforts recently focused on capturing nonlinear hysteretic behavior exhibited by piezoceramic materials. In this paper, effects of PZT nonlinearities on the dynamic response of a vibrating harvester device are investigated. A physics-based Gibbs energy model is employed to assess the response of a piezoelectric unimorph under the simplified assumption that the constitutive behavior of the active layer can be approximated using a piezoceramic single crystal model. Numerical simulations have been carried out in near-resonance conditions and comparisons with results obtained adopting linear constitutive equations for the PZT layer are reported. Numerical results confirm that nonlinear hysteretic effects can significantly increase the amount of harvested energy. Furthermore, they are relevant also when the device is operating in geometric linear conditions.