Experimental study and finite element analysis for piezoelectric impact energy harvesting using a bent metal beam

Linear uniform beams have been extensively investigated as a typical piezoelectric vibration energy harvesting mechanism in both conventional cantilever-beam-based harvester and a novel internal impact type energy harvester, the latter is of broad bandwidth and frequency up-converting capability and therefore quite suitable to low frequency ambient vibrations. To sufficiently utilize the space of the existing internal impact type energy harvester, a bent metal beam with distributed piezoelectric patches is proposed and investigated as the vibration energy harvesting module. A prototype harvester has been built and performances including the voltage and output power have been tested by experiments and analyzed by the finite element analysis. Both experiment and finite element analysis show that the proposed structure can effectively harvest vibration energy. And the optimal position for energy harvesting in this structure is also found. This work indicates that the frame of the existing internal impact type energy harvester may be used to harvest vibration energy, if it is bonded with distributed piezoelectric patches, which gives a way to increase its power density.