Piezoelectric based energy harvesting on low frequency vibrations of civil infrastructures

Abstract

Piezoelectric-based energy harvesting is an efficient way to convert ambient vibration energy into usable electric energy. The piezoelectric harvester can work as a sustainable and green power source for different electric devices such as sensors and implanted medical devices. However, its application on civil infrastructures has not been fully studied yet. This dissertation aimed to study and improve the piezoelectric-based energy harvesting on civil infrastructures, especially on bridge structures. To reach the objective, a more accurate model for piezoelectric composite beams was built first, which can be adopted for the modeling of different kinds of energy harvesters. The model includes both direct and inverse piezoelectric effects and can provide a better prediction for the dynamic response and energy output of a harvester. Secondly, to examine the piezoelectric-based energy harvesting on civil infrastructures, four concrete slab-on-girder bridges that represent the majority of bridges in the United States were modeled and used as the platforms for the energy harvesting. Piezoelectric cantilever–based harvesters were adopted for the energy harvesting performance simulation considering their wide usage. Different parameters of the bridges and the harvester were studied regarding to the harvesting performance. Two major problems for energy harvesting on civil infrastructures were identified, namely their low frequency vibrations and wide frequency ranges. Then, a multi-impact energy harvester was proposed to improve the harvesting performance under the vibration of low frequencies. The multi-impact was first introduced and theoretically proven. Theoretical and experimental studies for the multi-impact energy harvester were conducted. Both the results show an increased energy output power than the one from the conventional cantilever-based energy harvester. A parametric study was also presented which can serve as a guideline for the design and manufacture for the proposed harvester. Finally, a nonlinear energy harvester was proposed utilizing the magnet levitation. A larger band width was expected due to the stiffness non-linearity of the system. A theoretical model was built for the harvester and its energy output was simulated under the excitation of sinusoidal vibrations and bridge vibrations. The simulation results show a promising way to apply energy harvesting in the field of civil engineering.