Mechanical analysis of piezoelectric vibration energy harvesting devices

A modal model of the dynamics behavior of a bimorph vibration energy scavenger aimed at wireless system networks is proposed and validated via FEM simulations. Experimental set-ups are developed with the aim of assessing the validity of the model. The set-ups are tested by measuring the performances of commercially available energy scavengers. Repetitive bending tests allow determining the equivalent bending stiffness of the scavengers. Subsequent dynamics tests allow then obtaining results in terms of power vs. applied resistive loads. The validity of all the tools needed for the optimization of the performances of custom made scavengers in terms of their power outputs, while considering constraints such as dimensions and strength limits, is thus proven. They will be used to upgrade the design and the performances of vibration energy scavengers for wireless sensor networks.