As an alternative to beam-like structures, piezoelectric patch-based energy harvesters attached to thin plates can be readily integrated to plate-like structures in automotive, marine, and aerospace applications, in order to directly exploit structural vibration modes of the host system without mass loading and volumetric occupancy of cantilever attachments. In this paper, a multi-mode equivalent circuit model of a piezo-patch energy harvester integrated to a thin plate is developed and coupled with a standard AC-DC conversion circuit. Equivalent circuit parameters are obtained in two different ways: (1) from the modal analysis solution of a distributed-parameter analytical model and (2) from the finite-element numerical model of the harvester by accounting for two-way coupling. After the analytical modeling effort, multi-mode equivalent circuit representation of the harvester is obtained via electronic circuit simulation software SPICE. Using the SPICE software, electromechanical response of the piezoelectric energy harvester connected to linear and nonlinear circuit elements are computed. Simulation results are validated for the standard AC-AC and AC-DC configurations. For the AC input-AC output problem, voltage frequency response functions are calculated for various resistive loads, and they show excellent agreement with modal analysis-based analytical closed-form solution and with the finite-element model. For the standard ideal AC input-DC output case, a full-wave rectifier and a smoothing capacitor are added to the harvester circuit for conversion of the AC voltage to a stable DC voltage, which is also validated against an existing solution by treating the singlemode plate dynamics as a single-degree-of-freedom system.

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Vibration-based energy harvesting has drawn significant attention from different engineering disciplines over the last two decades. The studies in this research area have mostly concentrated on cantilevered piezoelectric beam harvesters under base excitations. As an alternative to beam arrangements, patch-based piezoelectric energy harvesters can be integrated on large plate-like structures such as panels of automotive, marine and aerospace applications to extract useful electrical power during their operation. In this paper, electroelastic finite element (FE) simulations of a patch-based piezoelectric energy harvester structurally integrated on a panel of a heavy duty vehicle are presented during different phases of operation. FE model of the panel together with a piezoceramic harvester patch is built using ANSYS software. The FE model takes into account coupled electromechanical dynamics and the fully-conductive electrode layers of the harvester patch. The vibration response of the panel as well as the voltage output of the harvester patch under operating conditions is simulated using the forces obtained from experimental measurements on the heavy duty vehicle. Excitation forces are calculated from operational acceleration measurements using matrix inversion method, which is a force identification technique. Two different operating conditions of the heavy duty vehicle are considered: stationary and moving on a test track while the engine was running. Using the excitation forces in the FE simulations, the electrical power generation of the harvester patch is predicted for a wide range of resistive loads. Electrical power outputs are then presented for short-circuit and open-circuit conditions. The numerical results show that the use of a harvester patch attached on a panel of a heavy duty vehicle generates reasonably well electrical power outputs.