Nonlinear analysis of piezoelectric energy harvesters from ambient and galloping vibrations

Abstract

The concept of harvesting energy from ambient and galloping vibrations of a bluff body with a triangular cross-section geometry is investigated. A piezoelectric transducer is attached to the transverse degree of freedom of the body in order to convert these vibrations into electrical energy. A coupled nonlinear distributed-parameter model is developed that takes into consideration the galloping force and moment nonlinearities and the base excitation effect. The aerodynamic loads are modeled by using the quasi-steady approximation. Linear analysis is performed to determine the effects of the electrical load resistance and wind speed on the global damping and frequency of the harvester as well as on the onset of instability. Then, a nonlinear analysis is performed to investigate the impacts of the base acceleration, wind speed, and electrical load resistance on the performance of the harvester and the associated nonlinear phenomena that take place. The results show that depending on the interaction between the base and galloping excitations and the considered values of the wind speed, base acceleration, and load resistance, different nonlinear phenomena arise and other ones disappear. Shortand open-circuit configurations for different wind speeds and base accelerations are determined. The results show that maximum levels of harvested power are accompanied by a minimum transverse displacement when varying the electrical load resistance.