Double-wall piezoelectric cylindrical energy harvester

Cylindrical structures possess the advantage of responding multi-directional vibrations compared with cantilevers. In this paper a double-wall cylindrical energy harvesting device is proposed to scavenge multimode mechanical vibrations. Compared with the single-wall energy harvester, it is found from the finite element analysis that the double-wall device generates higher output voltage, and responds to a wider oscillating frequency range. These advantages have been validated by experiments, where the open circuit output voltage for eight resonating modes has been characterized. For further investigation, dynamic responses of the device at these eight resonating modes have been characterized under various excitations. It is seen from the experiment that as the driven voltage of the excitation source increases from 5 V to 16 V, the output voltage increases and the corresponding quality factors reduces.