Nonlinear dynamics of post-buckled piezoelectric beams due to axial loads for energy harvesting applications

Abstract

In this work, we numerically and experimentally study the voltage generation of a piezoelectric energy harvester subjected to a static axial load. This applied force offers the possibility to modify the natural frequency of the device, which makes it highly attractive to achieve its operation in its resonance condition, maximizing its performance. In order to carry out our study, we obtained a reduced solution for the complex analytical model, that contemplates nonlinierity sources arising from inertial, geometric and constitutive relations for the piezoelectric material, according to the Multiple Scales Method (MSM). We compared the aforementioned solution with experimental results obtained under laboratory conditions showing good correlation. The numerical and experimental findings confirmed the possibility of varying the natural frequency of the device through a correct choice of axial load. Moreover, we could clearly identify the hardening and softening nonlinear behaviors for the pre- and post-buckling tates, respectively.