Model refinements and experimental testing of highly flexible piezoelectric energy harvesters

This paper addresses limitations to existing analytical models for piezoelectric energy harvesters. The presented model is targeted at predicting behaviours of highly flexible piezoelectric devices (FPEDs) and includes high orders of substrate and piezoelectric material nonlinearity, geometric nonlinearity, and additionally the effects of both self-weight and pre-stress. Validation through experimental testing is provided.The influence of self-weight on vibratory dynamics becomes important in FPEDs due to both material composition and dimension. The developed model facilitates the simulation of FPED performance mounted at specified angles to the horizontal. In one study, for a FPED of 120 mm in length, the resonant frequency changed by over 30 percent with mounting angle. Consideration of mounting orientation is advised as self-weight increases damping and significantly lowers FPED performance – over a 50 percent reduction in one presented case.