Experimental and Numerical Investigation of Vibration-Based Piezoelectric Energy Harvesting Device

A composite beam consisting of two layers is experimentally tested as an energy harvesting device. The substrate layer is made of aluminum and the piezoelectric layer is glued at 90% of the length of the alumina layer. The beam is clamped at one end and is free at the other. The cantilever is subjected to periodic kinematic excitation, and the tip acceleration as well as the generated electricity are measured. A 3D finite element model of the beam is created and the coupled mechanical and electrical fields are studied numerically. The results are compared with those obtained experimentally. A parametric study is conducted to investigate the influence of the loading parameters (frequency and amplitude of excitation) and the electric resistance in the circuit on the generated electricity. Conclusions about the optimal conditions with respect to energy harvesting are made. The importance of proper modelling of the contact between the PZT layer and the substrate is demonstrated.