Power enhancement of piezoelectric energy harvesters from aeroelastic vibrations

We investigate the level of harvested power from aeroelastic vibrations of an elastically- mounted wing supported by nonlinear springs. The energy is harvested by attaching a piezoelectric transducer to the plunge degree of freedom. A model that tightly couples the electromechanical model with the three dimensional unsteady vortex lattice method for the prediction of the unsteady aerodynamic loads is developed. The effects of the electrical load resistance and eccentricity between the elastic axis and the gravity axis on the level of the harvested power, pitch and plunge amplitudes are investigated for a range of operating wind speeds. The results show that there is an optimum value of load resistance that maximizes the level of harvested power. The results also show that the nonlinear torsional spring plays an important role in enhancing the level of the harvested power. Furthermore, the harvested power can be significantly enhanced by properly choosing the eccentricity.