Electromechanical modeling and analytical investig

Authors: Abdolreza Pasharavesh M T Ahmadian H Zohoor

Publish Date: 2016/08/30

Volume: 13, Issue: 4, Pages: 499-514

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Abstract

Piezoelectric materials are extensively applied for vibrational energy harvesting especially in microscale devices where other energy conversion mechanisms such as electromagnetic and electrostatic methods encounter fabrication limitations A cantilevered piezoelectric bimorph beam with an attached proof tip mass for the sake of resonance frequency reduction is the most common structure in vibrational harvesters According to the amplitude and frequency of applied excitations and physical parameters of the harvester the system may be pushed into a nonlinear regime which arises from material or geometric nonlinearities In this study nonlinear dynamics of a piezoelectric bimorph harvester implementing constitutive relations of nonlinear piezoelectricity together with nonlinear curvature and shortening effect relations is investigated To achieve this goal first of all a comprehensive fullycoupled electromechanical nonlinear model is presented through a variational approach The governing nonlinear partial differential equations of the proposed model are order reduced and solved by means of the perturbation method of multiple scales Results are presented for a PZT/Silicon/PZT laminated beam as a case study Findings indicate that material nonlinearities of the PZT layer has the dominant effect leading to softening behavior of the frequency response At the primary resonance different frequency responses of the extracted power can be distinguished according to the excitation amplitude which is due to harmonic generation as a result of piezoelectric nonlinearity The extracted power is analytically computed and validated with a good agreement by a numerical solution

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