Date

2017

Document Type

Thesis

Degree

Master of Science

Department

Structural Engineering

First Adviser

Bocchini, Paolo

Abstract

Piezoelectric devices have had specific applications in the energy harvesting industry for several years. The simplicity of these generators is making them attractive for researchers in a wide range of engineering applications. The goal of this work is to develop a rigorous procedure to quantify the electrical energy generation potential from piezoelectric devices, considering the coupled problem involving random wind loads, structural vibration, electro-mechanics and energy collection. With that in mind, a finite element model of a piezoelectric device is developed to determine the energy that can be harvested from the vibration in a sample bridge structure. The load considered to act on the bridge and, consequently, on the device is the wind, modeled by the Kaimal Spectrum. The analysis is performed in a probabilistic fashion, using Monte Carlo simulation and considering a large set of wind load samples generated by spectral representation. The harvester device is a cantilever beam constituted of a rubber core with piezoelectric layers, at the top and bottom, which is modeled using the Finite Element Method (FEM). The output obtained from the finite element model is the electrical potential. The beam is attached to a one-loop simple electrical circuit where the total energy generated and supplied to a resistor is computed. The results can be used to obtain the variation of average voltage and power supplied to an electric system and thus, for a given application, help to design the energy management system. The research on the theoretical FE model provides a method for an efficient and practical harvesting from bridges or other structures exposed to wind loads by a piezoelectric harvester device fixed on it.

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