Issues in validation of performances of piezoelectric vibration-based energy harvesters

Vibration energy harvesting devices based on piezoelectric bimorphs have attracted widespread attention. In this work experimental set-ups are developed to assess the performances of commercially available piezoelectric energy harvesters. Bending tests allow determining the equivalent bending stiffness of the scavengers. On the other hand, dynamic tests allow obtaining frequency response functions in terms of produced voltage and power outputs vs. base acceleration around the fundamental resonance frequency. The results allow determining the influence of the voltage feedback on the dynamic response of the devices, the dependence of output voltages and powers on the applied resistive loads, the values of the loads and frequencies for which the output power is maximized, as well as the comparison of the experimental data with those obtained by using the recently developed coupled electromechanical modal model. All of this creates the preconditions for the development of optimized vibration energy harvesting devices.