Degradation of piezoelectric device as an energy harvester for non-sinusoidal stress condition
Piezoelectric materials have been used extensively for applications in microelectromechanical systems, electromechanical devices, civil infrastructure and transportation, and smart devices. The performance of these materials is largely affected by their loading and unloading history when used in electromechanical applications. Lead Zirconium Titanate (PZT), a class of piezoelectric ceramics, which upon repetitive cyclic compressive load undergoes both electrical and mechanical degradation over a period and a number of cycles. The degradation of piezoelectric properties with the application of cyclic compressive loading and the mechanical fatigue behavior were investigated on PZT-5A. Few samples were modified like sectioning across the thickness, laminating and electroding them in series and parallel conditions. Various properties of PZT sample such as d33, €r, capacitance, tangent loss, power and voltage outputs, and microstructure are measured at equivalent roadways traffic conditions and frequency dependence under MTS Acumen 3 electrodynamic test system. Tests are done at a various number of cycles, and performance of power converting properties is determined. Consecutive tests are used to compare relaxation and long term degradation in samples with different fabrication process. Degradation rates are calculated, compared and predicted for the best suitable sample satisfying the roadway conditions. The Proper mechanism, explanations, and reasons are given for the degradation.