Resonant nonlinearities of piezoelectric macro-fiber composite cantilevers with interdigitated electrodes in energy harvesting

TLDR: In this article, a nonlinear non-conservative dynamics of macro-fiber composite (MFC) piezoelectric structures, guided by rigorous experiments, for resonant vibration-based energy harvesting, was explored.

Abstract: We explore the modeling and analysis of nonlinear nonconservative dynamics of macro-fiber composite (MFC) piezoelectric structures, guided by rigorous experiments, for resonant vibration-based energy harvesting, as well as other applications leveraging the direct piezoelectric effect, such as resonant sensing. The MFCs employ piezoelectric fibers of rectangular cross section embedded in Kapton with interdigitated electrodes to exploit the 33-mode of piezoelectricity. Existing modeling and analysis efforts for resonant nonlinearities have so far considered conventional piezoceramics that use the 31-mode of piezoelectricity. In the present work, we develop a framework to represent and predict nonlinear electroelastic dynamics of MFC bimorph cantilevers under resonant base excitation for primary resonance behavior. The interdigitated electrodes are shunted to a set of resistive electrical loads to quantify the electrical power output. Experiments are conducted on a set of MFC bimorphs over a broad range of mechanical excitation levels to identify the types of nonlinearities present and to compare the harmonic balance model predictions and experiments. The experimentally observed interaction of quadratic piezoelectric material softening and cubic geometric hardening effects is captured and demonstrated by the model. It is shown that the linearized version of the model yields highly inaccurate results for typical base acceleration levels and frequencies involved in vibration energy harvesting, while the nonlinear framework presented here can accurately predict the amplitude-dependent resonant frequency response.